建筑施工混凝土裂缝处理中英文对照外文翻译文献
混凝土工艺中英文对照外文翻译文献
混凝土工艺中英文对照外文翻译文献混凝土工艺中英文对照外文翻译文献(文档含英文原文和中文翻译)Concrete technology and developmentPortland cement concrete has clearly emerged as the material of choice for the construction of a large number and variety of structures in the world today. This is attributed mainly to low cost of materials and construction for concrete structures as well as low cost of maintenance.Therefore, it is not surprising that many advancements in concrete technology have occurred as a result of two driving forces, namely the speed of construction and the durability of concrete.During the period 1940-1970, the availability of high early strength portland cements enabled the use of high water content in concrete mixtures that were easy to handle. This approach, however, led to serious problems with durability of structures, especially those subjected to severe environmental exposures.With us lightweight concrete is a development mainly of the last twenty years.Concrete technology is the making of plentiful good concrete cheaply. It includes the correct choice of the cement and the water, and the right treatment of the aggregates. Those which are dug near by and therefore cheap, must be sized, washed free of clay or silt, and recombined in the correct proportions so as to make a cheap concrete which is workable at a low water/cement ratio, thus easily comoacted to a high density and therefore strong.It hardens with age and the process of hardening continues for a long time after the concrete has attained sufficient strength.Abrams’law, perhaps the oldest law of concrete technology, states that the strength of a concrete varies inversely with its water cement ratio. This means that the sand content (particularly the fine sand which needs much water) must be reduced so far as possible. The fact that the sand “drinks” large quantities of water can easily be established by mixing several batches of x kg of cement with y kg of stone and the same amount of water but increasing amounts of sand. However if there is no sand the concrete will be so stiff that it will be unworkable thereforw porous and weak. The same will be true if the sand is too coarse. Therefore for each set of aggregates, the correct mix must not be changed without good reason. This applied particularly to the water content.Any drinkable and many undrinkable waters can be used for making concrete, including most clear waters from the sea or rivers. It is important that clay should be kept out of the concrete. The cement if fresh can usually be chosen on the basis of the maker’s certificates of tensile or crushing tests, but these are always made with fresh cement. Where strength is important , and the cement at the site is old, it should be tested.This stress , causing breakage,will be a tension since concretes are from 9 to 11times as strong in compression as in tension, This stress, the modulus of rupture, will be roughly double the direct tensile breaking stress obtained in a tensile testing machine,so a very rough guess at the conpressive strength can be made by multiplying the modulus of rupture by 4.5. The method can be used in combination with the strength results of machine-crushed cubes or cylinders or tensile test pieces but cannot otherwise be regarded as reliable. With these comparisons, however, it is suitable for comparing concretes on the same site made from the same aggregates and cement, with beams cast and tested in the same way.Extreme care is necessary for preparation,transport,plating and finish of concrete in construction works.It is important to note that only a bit of care and supervision make a great difference between good and bad concrete.The following factors may be kept in mind in concreting works.MixingThe mixing of ingredients shall be done in a mixer as specified in the contract.Handling and ConveyingThe handling&conveying of concrete from the mixer to the place of final deposit shall be done as rapidly as practicable and without any objectionable separation or loss of ingredients.Whenever the length of haul from the mixing plant to the place of deposit is such that the concrete unduly compacts or segregates,suitable agitators shall be installed in the conveying system.Where concrete is being conveyed on chutes or on belts,the free fall or drop shall be limited to 5ft.(or 150cm.) unless otherwise permitted.The concrete shall be placed in position within 30 minutes of its removal from the mixer.Placing ConcreteNo concrete shall be placed until the place of deposit has been thoroughly inspected and approved,all reinforcement,inserts and embedded metal properly security in position and checked,and forms thoroughly wetted(expect in freezing weather)or oiled.Placing shall be continued without avoidable interruption while the section is completed or satisfactory construction joint made.Within FormsConcrete shall be systematically deposited in shallow layers and at such rate as to maintain,until the completion of the unit,a plastic surface approximately horizontal throughout.Each layer shall be thoroughly compacted before placing the succeeding layer.CompactingMethod. Concrete shall be thoroughly compacted by means of suitable tools during and immediately after depositing.The concrete shall be worked around all reinforcement,embedded fixtures,and into the comers of the forms.Every precaution shall be taken to keep the reinforcement and embedded metal in proper position and to prevent distortion.Vibrating. Wherever practicable,concrete shall be internally vibrated within the forms,or in the mass,in order to increase the plasticity as to compact effectively to improve the surface texture and appearance,and to facilitate placing of the concrete.Vibration shall be continued the entire batch melts to a uniform appearance and the surface just starts to glisten.A minute film of cement paste shall be discernible between the concrete and the form and around the reinforcement.Over vibration causing segregation,unnecessary bleeding or formation of laitance shall be avoided.The effect spent on careful grading, mixing and compaction of concrete will be largely wasted if the concrete is badly cured. Curing means keeping the concretethoroughly damp for some time, usually a week, until it has reached the desired strength. So long as concrete is kept wet it will continue to gain strength, though more slowly as it grows older.Admixtures or additives to concrete are materials are materials which are added to it or to the cement so as to improve one or more of the properties of the concrete. The main types are:1. Accelerators of set or hardening,2. Retarders of set or hardening,3. Air-entraining agents, including frothing or foaming agents,4. Gassing agents,5. Pozzolanas, blast-furnace slag cement, pulverized coal ash,6. Inhibitors of the chemical reaction between cement and aggregate, which might cause the aggregate to expand7. Agents for damp-proofing a concrete or reducing its permeability to water,8. Workability agents, often called plasticizers,9. Grouting agents and expanding cements.Wherever possible, admixtures should be avouded, particularly those that are added on site. Small variations in the quantity added may greatly affect the concrete properties in an undesiraale way. An accelerator can often be avoided by using a rapid-hardening cement or a richer mix with ordinary cement, or for very rapid gain of strength, high-alumina cement, though this is very much more expensive, in Britain about three times as costly as ordinary Portland cement. But in twenty-four hours its strength is equal to that reached with ordinary Portland cement in thirty days.A retarder may have to be used in warm weather when a large quantity of concrete has to be cast in one piece of formwork, and it is important that the concrete cast early in the day does not set before the last concrete. This occurs with bridges when they are cast in place, and the formwork necessarily bends under the heavy load of the wet concrete. Some retarders permanently weaken the concrete and should not be used without good technical advice.A somewhat similar effect,milder than that of retarders, is obtained with low-heat cement. These may be sold by the cement maker or mixed by the civil engineering contractor. They give out less heat on setting and hardening, partly because they harden more slowly, and they are used in large casts such as gravity dams, where the concrete may take years to cool down to the temperature of the surrounding air. In countries like Britain or France, where pulverized coal is burnt in the power stations, the ash, which is very fine, has been mixed with cement to reduce its production of heat and its cost without reducing its long-term strength. Up to about 20 per cent ash by weight of the cement has been successfully used, with considerable savings in cement costs.In countries where air-entraining cement cement can be bought from the cement maker, no air-entraining agent needs to be mixed in .When air-entraining agents draw into the wet cement and concrete some 3-8 percent of air in the form of very small bubbles, they plasticize the concrete, making it more easily workable and therefore enable the water |cement ratio to be reduced. They reduce the strength of the concrete slightly but so little that in the United States their use is now standard practice in road-building where heavy frost occur. They greatly improve the frost resistance of the concrete.Pozzolane is a volcanic ash found near the Italian town of Puzzuoli, which is a natural cement. The name has been given to all natural mineral cements, as well as to the ash from coal or the slag from blast furnaces, both of which may become cements when ground and mixed with water. Pozzolanas of either the industrial or the mineral type are important to civil engineers because they have been added to oridinary Portland cement in proportions up to about 20 percent without loss of strength in the cement and with great savings in cement cost. Their main interest is in large dams, where they may reduce the heat given out by the cement during hardening. Some pozzolanas have been known to prevent the action between cement and certain aggregates which causes the aggregate to expand, and weaken or burst the concrete.The best way of waterproof a concrete is to reduce its permeability by careful mix design and manufacture of the concrete, with correct placing and tighr compaction in strong formwork ar a low water|cement ratio. Even an air-entraining agent can be used because the minute pores are discontinuous. Slow, careful curing of the concrete improves the hydration of the cement, which helps to block the capillary passages through the concrete mass. An asphalt or other waterproofing means the waterproofing of concrete by any method concerned with the quality of the concrete but not by a waterproof skin.Workability agents, water-reducing agents and plasticizers are three names for the same thing, mentioned under air-entraining agents. Their use can sometimes be avoided by adding more cement or fine sand, or even water, but of course only with great care.The rapid growth from 1945 onwards in the prestressing of concrete shows that there was a real need for this high-quality structural material. The quality must be high because the worst conditions of loading normally occur at the beginning of the life of the member, at the transfer of stress from the steel to the concrete. Failure is therefore more likely then than later, when the concrete has become stronger and the stress in the steel has decreased because of creep in the steel and concrete, and shrinkage of the concrete. Faulty members are therefore observed and thrown out early, before they enter the structure, or at least before it The main advantages of prestressed concrete in comparison with reinforced concrete are :①The whole concrete cross-section resists load. In reinforced concrete about half the section, the cracked area below the neutral axis, does no useful work. Working deflections are smaller.②High working stresses are possible. In reinforced concrete they are not usually possible because they result in severe cracking which is always ugly and may be dangerous if it causes rusting of the steel.③Cracking is almost completely avoided in prestressed concrete.The main disadvantage of prestressed concrete is that much more care is needed to make it than reinforced concrete and it is therefore more expensive, but because it is of higher quality less of it needs to be needs to be used. It can therefore happen that a solution of a structural problem may be cheaper in prestressed concrete than in reinforced concrete, and it does often happen that a solution is possible with prestressing but impossible without it.Prestressing of the concrete means that it is placed under compression before it carries any working load. This means that the section can be designed so that it takes no tension or very little under the full design load. It therefore has theoretically no cracks and in practice very few. The prestress is usually applied by tensioning the steel before the concrete in which it is embedded has hardened. After the concrete has hardened enough to take the stress from the steel to the concrete. In a bridge with abutments able to resist thrust, the prestress can be applied without steel in the concrete. It is applied by jacks forcing the bridge inwards from the abutments. This methods has the advantage that the jacking force, or prestress, can be varied during the life of the structure as required.In the ten years from 1950 to 1960 prestressed concrete ceased to be an experinmental material and engineers won confidence in its use. With this confidence came an increase in the use of precast prestressed concrete particularly for long-span floors or the decks of motorways. Whereever the quantity to be made was large enough, for example in a motorway bridge 500 m kong , provided that most of the spans could be made the same and not much longer than 18m, it became economical to usefactory-precast prestressed beams, at least in industrial areas near a precasting factory prestressed beams, at least in industrial areas near a precasting factory. Most of these beams are heat-cured so as to free the forms quickly for re-use.In this period also, in the United States, precast prestressed roof beams and floor beams were used in many school buildings, occasionally 32 m long or more. Such long beams over a single span could not possibly be successful in reinforced concrete unless they were cast on site because they would have to be much deeper and much heavier than prestressed concrete beams. They would certainlly be less pleasing to the eye and often more expensive than the prestressed concrete beams. These school buildings have a strong, simple architectural appeal and will be a pleasure to look at for many years.The most important parts of a precast prestressed concrete beam are the tendons and the concrete. The tendons, as the name implies, are the cables, rods or wires of steel which are under tension in the concrete.Before the concrete has hardened (before transfer of stress), the tendons are either unstressed (post-tensioned prestressing) or are stressed and held by abutments outside the concrete ( pre-tensioned prestressing). While the concrete is hardening it grips each tendon more and more tightly by bond along its full length. End anchorages consisting of plates or blocks are placed on the ends of the tendons of post-tensioned prestressed units, and such tendons are stressed up at the time of transfer, when the concrete has hardened sufficiently. In the other type of pretressing, with pre-tensioned tendons, the tendons are released from external abutments at the moment of transfer, and act on the concrete through bond or archorage or both, shortening it by compression, and themselves also shortening and losing some tension.Further shortening of the concrete (and therefore of the steel) takes place with time. The concrete is said to creep. This means that it shortens permanently under load and spreads the stresses more uniformly and thus more safely across its section. Steel also creeps, but rather less. The result of these two effects ( and of the concrete shrinking when it dries ) is that prestressed concrete beams are never more highly stressed than at the moment of transfer.The factory precasting of long prestressed concrete beams is likely to become more and more popular in the future, but one difficulty will be road transport. As the length of the beam increases, the lorry becomes less and less manoeuvrable until eventually the only suitable time for it to travel is in the middle of the night when traffic in the district and the route, whether the roads are straight or curved. Precasting at the site avoids these difficulties; it may be expensive, but it has often been used for large bridge beams.混凝土工艺及发展波特兰水泥混凝土在当今世界已成为建造数量繁多、种类复杂结构的首选材料。
建筑施工中英文对照外文翻译文献
建筑施工中英文对照外文翻译文献建筑施工中英文对照外文翻译文献(文档含英文原文和中文翻译)外文：Building construction concrete crack ofprevention and processingAbstractThe crack problem of concrete is a widespread existence but again difficult in solve of engineering actual problem, this text carried on a study analysis to a little bit familiar crack problem in the concrete engineering, and aim at concrete the circumstance put forward some prevention, processing measure.Keyword:Concrete crack prevention processingForewordConcrete's ising 1 kind is anticipate by the freestone bone, cement, water and other mixture but formation of the in addition material of quality brittleness not and all material.Because the concrete construction transform with oneself, control etc. a series problem, harden model of in the concrete existence numerous tiny hole, spirit cave and tiny crack, is exactly because these beginning start blemish of existence just make the concrete present one some not and all the characteristic of quality.The tiny crack is a kind of harmless crack and accept concrete heavy, defend Shen and a little bit other use function not a creation to endanger.But after the concrete be subjected to lotus carry, difference in temperature etc. function, tiny crack would continuously of expand with connect, end formation we can see without the aid of instruments of macro view the crack be also the crack that the concrete often say in the engineering.Concrete building and Gou piece usually all take sewer to make of, because of crack of existence and development usually make inner part of reinforcing bar etc. material creation decay, lower reinforced concrete material of loading ability, durable and anti- Shen ability, influence building of external appearance, service life, severity will threat arrive people's life and property safety.A lot of all of crash of engineerings is because of the unsteady development of the crack with the result that.Modern age scienceresearch with a great deal of of the concrete engineering practice certificate, in the concrete engineering crack problem is ineluctable, also acceptable in certainly of the scope just need to adopt valid of measure will it endanger degree control at certain of scope inside.The reinforced concrete norm is also explicit provision:Some structure at place of dissimilarity under the condition allow existence certain the crack of width.But at under construction should as far as possible adopt a valid measure control crack creation, make the structure don't appear crack possibly or as far as possible decrease crack of amount and width, particularly want to as far as possible avoid harmful crack of emergence, insure engineering quality thus.Concrete crack creation of the reason be a lot of and have already transformed to cause of crack:Such as temperature variety, constringency, inflation, the asymmetry sink to sink etc. reason cause of crack;Have outside carry the crack that the function cause;Protected environment not appropriate the crack etc. caused with chemical effect.Want differentiation to treat in the actual engineering, work°out a problem according to the actual circumstance.In the concrete engineering the familiar crack and the prevention1.Stem Suo crack and preventionStem the Suo crack much appear after the concrete protect be over of a period of time or concrete sprinkle to build to complete behind of around a week.In the cement syrup humidity of evaporate would creation stem Suo, and this kind of constringency is can't negative.Stem Suo crack of the creation be main is because of concrete inside outside humidity evaporate degree dissimilarity but cause to transform dissimilarity of result:The concrete is subjected to exterior condition of influence, surface humidity loss lead quick, transform bigger, inner part degree of humidity variety smaller transform smaller, bigger surface stem the Suo transform to be subjected to concrete inner part control, creation more big pull should dint but creation crack.The relative humidity is more low, cement syrup body stem Suo more big, stem the Suo crack be more easy creation.Stem the Suo crack is much surface parallel lines form or the net shallow thin crack, width many between 0.05-0.2 mm, the flat surface part much see in the big physical volume concrete and follow it more in thinner beam plank short todistribute.Stem Suo crack usually the anti- Shen of influence concrete, cause the durable of the rust eclipse influence concrete of reinforcing bar, under the function of the water pressure dint would creation the water power split crack influence concrete of loading dint etc..Concrete stem the Suo be main with water ash of the concrete ratio, the dosage of the composition, cement of cement, gather to anticipate of the dosage of the property and dosage, in addition etc. relevant.Main prevention measure:While being to choose to use the constringency quantity smaller cement, general low hot water mire and powder ash from stove cement in the adoption, lower the dosage of cement.Two is a concrete of stem the Suo be subjected to water ash ratio of influence more big, water ash ratio more big, stem Suo more big, so in the concrete match the ratio the design should as far as possible control good water ash ratio of choose to use, the Chan add in the meantime accommodation of reduce water.Three is strict control concrete mix blend with under construction of match ratio, use of concrete water quantity absolute can't big in match ratio design give settle of use water quantity.Four is the earlier period which strengthen concrete to protect, and appropriate extension protect of concrete time.Winter construction want to be appropriate extension concrete heat preservation to overlay time, and Tu2 Shua protect to protect.Five is a constitution the accommodation is in the concrete structure of the constringency sew.2.The Su constringency crack and preventionSu constringency is the concrete is before condense, surface because of lose water quicker but creation of constringency.The Su constringency crack is general at dry heat or strong wind the weather appear, crack's much presenting in the center breadth, both ends be in the centerthin and the length be different, with each other not coherent appearance.Shorter crack general long 20-30 cm, the longer crack can reach to a 2-3 m, breadth 1-5 mm.It creation of main reason is:The concrete is eventually almost having no strength or strength before the Ning very small, perhaps concrete just eventually Ning but strength very hour, be subjected to heat or compare strong wind dint of influence, the concrete surface lose water to lead quick, result in in the capillary creation bigger negative press but make a concrete physical volume sharplyconstringency, but at this time the strength of concrete again can't resist its constringency, therefore creation cracked.The influence concrete Su constringency open the main factor of crack to have water ash ratio, concrete of condense time, environment temperature, wind velocity, relative humidity...etc..Main prevention measure:One is choose to use stem the Suo value smaller higher Huo sour salt of the earlier period strength or common the Huo sour brine mire.Two is strict the control water ash ratio, the Chan add to efficiently reduce water to increment the collapse of concrete fall a degree and with easy, decrease cement and water of dosage.Three is to sprinkle before building concrete, water basic level and template even to soak through.Four is in time to overlay the perhaps damp grass mat of the plastics thin film, hemp slice etc., keep concrete eventually before the Ning surface is moist, perhaps spray to protect etc. to carry on protect in the concrete surface.Five is in the heat and strong wind the weather to want to establish to hide sun and block breeze facilities, protect in time.3.Sink to sink crack and preventionThe creation which sink to sink crack is because of the structure foundation soil quality not and evenly, loose soft or return to fill soil dishonest or soak in water but result in the asymmetry sink to decline with the result that;Perhaps because of template just degree shortage, the template propped up to once be apart from big or prop up bottom loose move etc. to cause, especially at winter, the template prop up at jelly soil up, jelly the soil turn jelly empress creation asymmetry to sink to decline and cause concrete structure creation crack.This kind crack many is deep enter or pierce through sex crack, it alignment have something to do with sinking to sink a circumstance, general follow with ground perpendicular or present 30 °s-45 °Cape direction development, bigger sink to sink crack, usually have certain of wrong, crack width usually with sink to decline quantity direct proportion relation.Crack width under the influence of temperature variety smaller.The foundation after transform stability sink to sink crack also basic tend in stability.Main prevention measure:One is rightness loose soft soil, return to fill soil foundation a construction at the upper part structure front should carry on necessity ofHang solid with reinforce.Two is the strength that assurance template is enough and just degree, and prop up firm, and make the foundation be subjected to dint even.Three is keep concrete from sprinkle infusing the foundation in the process is soak by water.Four is time that template tore down to can't be too early, and want to notice to dismantle a mold order of sequence.Five is at jelly soil top take to establish template to notice to adopt certain of prevention measure.4.Temperature crack and preventionTemperature crack much the occurrence is in big surface or difference in temperature variety of the physical volume concrete compare the earth area of the concrete structure.Concrete after sprinkling to build, in the hardening the process, cement water turn a creation a great deal of of water turn hot, .(be the cement dosage is in the 350-550 kg/m 3, each sign square the rice concrete will release a calories of 17500-27500 kJ and make concrete internal thus the temperature rise to reach to 70 ℃or so even higher)Because the physical volume of concrete be more big, a great deal of of water turn hot accumulate at the concrete inner part but not easy send forth, cause inner part the temperature hoick, but the concrete surface spread hot more quick, so formation inside outside of bigger difference in temperature, the bigger difference in temperature result in inner part and exterior hot the degree of the bulge cold Suo dissimilarity, make concrete surface creation certain of pull should dint.When pull should dint exceed the anti- of concrete pull strength extreme limit, concrete surface meeting creation crack, this kind of crack much occurrence after the concrete under construction period.In the concrete of under construction be difference in temperature variety more big, perhaps is a concrete to be subjected to assault of cold wave etc., will cause concrete surface the temperature sharply descend, but creation constringency, surface constringency of the concrete be subjected to inner part concrete of control, creation very big of pull should dint but creation crack, this kind of crack usually just in more shallow scope of the concrete surface creation.The alignment of the temperature crack usually none settle regulation, big area structure the crack often maneuver interleave;The size bigger structure of the beam plank length, the crack run parallel with short side more;Thorough with pierce throughsex of temperature crack general and short side direction parallelism or close parallelism, crack along long side cent the segment appear, in the center more airtight.Crack width the size be different, be subjected to temperature variety influence more obvious, winter compare breadth, summer more narrow.The concrete temperature crack that the heat inflation cause is usually in the center the thick both ends be thin, but cold Suo crack of thick thin variety not too obvious.The emergence of the this kind crack will cause the rust eclipse of reinforcing bar, the carbonization of concrete, the anti- jelly which lower concrete melt, anti- tired and anti- Shen ability etc..Main prevention measure:One is as far as possible choose to use low hot or medium hot water mire, like mineral residue cement, powder ash from stove cement...etc..Two is a decrease cement dosage, cement dosage as far as possible the control is in the 450 kg/m 3 following.Three is to lower water ash ratio, water ash of the general concrete ratio control below 0.6.Four is improvement the bone anticipate class to go together with, the Chan add powder ash from stove or efficiently reduce water etc. to come to reduce cement dosage and lower water to turn hot.Five is an improvement concrete of mix blend to process a craft, lower sprinkle of concrete to build temperature.Six is the in addition that the Chan add a have of fixed amount to reduce water and increase Su, slow Ning etc. function in the concrete, improvement the concrete mix to match a thing of mobility, protect water, lower water to turn hot, postpone hot Feng of emergence time.Seven is the heat season sprinkle to build can the adoption take to establish to hide sun plank etc. assistance measure control concrete of Wen Sheng, lower to sprinkle temperature of build the concrete.Eight is the temperature of big physical volume concrete should the dint relate to structure size, concrete structure size more big, temperature should dint more big, so want reasonable arrangement construction work preface, layering, cent the piece sprinkle to build, for the convenience of in spread hot, let up control.Nine is at great inner part constitution of the physical volume concrete cool off piping, cold water perhaps cold air cool off, let up concrete of inside outside difference in temperature.Ten is the supervision which strengthen concrete temperature, adopt to cool off in time, protection measure.11 is to reserve temperature constringency to sew.12 is to let up to control, sprinkle proper before building concrete in the Ji rockand old concrete top build a 5 mm or so sand mat a layer or usage asphalt etc. material Tu2 Shua.13 is to strengthen concrete to protect, the concrete after sprinkle build use moist grass Lian in time, hemp slice's etc. overlay, and attention sprinkle water to protect, appropriate extension protect time, assurance the concrete surface be slow-moving cool off.At the cold season, concrete surface should constitution heat preservation measure, in order to prevent cold wave assault.14 is the allocation be a little amount in the concrete of reinforcing bar perhaps add fiber material concrete of temperature crack control at certain of scope inside.5.Crack and prevention that the chemical reaction causeAlkali bone's anticipating the crack that reaction crack and reinforcing bar rust eclipse cause is the most familiar in the reinforced concrete structure of because of chemical reaction but cause of crack.The concrete blend a future reunion creation some alkalescence ion, these ion with some activity the bone anticipate creation chemical reaction and absorb surroundings environment in of water but the physical volume enlarge, make concrete crisp loose, inflation open crack.In this kind of crack general emergence concrete structure usage period, once appear very difficult remediable, so should at under construction adopt valid the measure carry on prevention.Main of prevention measure:While being to choose to anticipate with the alkali activity small freestone bone.Two is the in addition which choose to use low lye mire with low alkali or have no alkali.Three is the Chan which choose to use accommodation with anticipate to repress an alkali bone to anticipate reaction.Because the concrete sprinkle to build, flap Dao bad perhaps is a reinforcing bar protection layer thinner, the harmful material get into concrete to make reinforcing bar creation rust eclipse, the reinforcing bar physical volume of the rust eclipse inflation, cause concrete bulge crack, the crack of this kind type much is a crack lengthways, follow the position of reinforcing bar ually of prevent measure from have:One is assurance reinforcing bar protection the thickness of the layer.Two is a concrete class to go together with to want good.Three is a concrete to sprinkle to note and flap Dao airtight solid.Four is a reinforcing bar surface layer Tu2 Shua antisepsiscoating.Crack processingThe emergence of the crack not only would influence structure of whole with just degree, return will cause the rust eclipse of reinforcing bar, acceleration concrete of carbonization, lower durable and anti- of concrete tired, anti- Shen ability.Therefore according to the property of crack and concrete circumstance we want differentiation to treat, in time processing, with assurance building of safety usage.The repair measure of the concrete crack is main to have the following some method:Surface repair method, infuse syrup, the Qian sew method, the structure reinforce a method, concrete displacement method, electricity chemistry protection method and imitate to living from heal method.Surface repair the method be a kind of simple, familiar of repair method, it main be applicable to stability and to structure loading the ability don't have the surface crack of influence and deep enter crack of processing.The processing measure that is usually is a surface in crack daubery cement syrup, the wreath oxygen gum mire or at concrete surface Tu2 Shua paint, asphalt etc. antisepsis material, at protection of in the meantime for keeping concrete from continue under the influence of various function to open crack, usually can adoption the surface in crack glue to stick glass fiber cloth etc. measure.1, infuse syrup, the Qian sew methodInfuse a syrup method main the concrete crack been applicable to have influence or have already defend Shen request to the structure whole of repair, it is make use of pressure equipments gum knot the material press into the crack of concrete, gum knot the material harden behind and concrete formation one be whole, thus reinforce of purpose.The in common use gum knot material has the cement the syrup, epoxy, A Ji C Xi sour ester and gather ammonia ester to equalize to learn material.The Qian sew a method is that the crack be a kind of most in common use method in, it usually is follow the crack dig slot, the Qian fill Su in the slot or rigid water material with attain closing crack of purpose.The in common use Su material has PVC gum mire,plastics ointment, the D Ji rubber etc.;In common use rigid water material is the polymer cement sand syrup.2, the structure reinforce a methodWhen the crack influence arrive concrete structure of function, will consideration adopt to reinforce a method to carry on processing to the concrete structure.The structure reinforce medium in common use main have the following a few method:The piece of enlargement concrete structure in every aspect accumulate, outside the Cape department of the Gou piece pack type steel, adoption prepare should the dint method reinforce, glue to stick steel plate to reinforce, increase to establish fulcrum to reinforce and jet the concrete compensation reinforce.3, concrete displacement methodConcrete displacement method is processing severity damage concrete of a kind of valid method, this method be first will damage of the concrete pick and get rid of, then again displacement go into new of concrete or other material.The in common use displacement material have:Common concrete or the cement sand syrup, polymer or change sex polymer concrete or sand syrup.4, the electricity chemistry protection methodThe electricity chemistry antisepsis is to make use of infliction electric field in lie the quality of electricity chemical effect, change concrete or reinforced concrete the environment appearance of the place, the bluntness turn reinforcing bar to attain the purpose of antisepsis.Cathode protection method, chlorine salt's withdrawing a method, alkalescence to recover a method is a chemistry protection method in three kinds of in common use but valid method.The advantage of this kind of method is a protection method under the influence of environment factor smaller, apply reinforcing bar, concrete of long-term antisepsis, since can used for crack structure already can also used for new set up structure.5, imitate to living from legal moreImitate to living from heal the method be a kind of new crack treatment, its mimicry living creature organization secrete a certain material towards suffering wound part auto, but make the wound part heal of function, join some and special composition(suchas contain to glue knot of the liquid Xin fiber or capsule) in the concrete of the tradition the composition, at concrete inner part formation the intelligence type imitate to living from heal nerve network system, be the concrete appear crack secrete a parts of liquid Xin fiber can make the crack re- heal.ConclusionThe crack is widespread in the concrete structure existence of a kind of phenomenon, it of emergence not only will lower the anti- Shen of building ability, influence building of usage function, and will cause the rust eclipse of reinforcing bar, the carbonization of concrete, lower the durable of material, influence building of loading ability, so want to carry on to the concrete crack earnest research, differentiation treat, adoption reasonable of the method carry on processing, and at under construction adopt various valid of prevention measure to prevention crack of emergence and development, assurance building and Gou piece safety, stability work.From《CANADIAN JOURNAL OF CIVIL ENGINEERING》译文：建筑施工混凝土裂缝的预防与处理混凝土的裂缝问题是一个普遍存在而又难于解决的工程实际问题，本文对混凝土工程中常见的一些裂缝问题进行了探讨分析，并针对具体情况提出了一些预防、处理措施。
现浇楼板裂缝外文文献翻译中英文
外文文献翻译(含：英文原文及中文译文)英文原文Roduction and prevention and cure of the crack of skyscraperRothbard MAlong with the speeding of town house construction step, not a few areas with small residences set up one after another, many inhabitants move continuously into the new residence, their quality to housing request is more and more high, particularly pay attention to very much to some cracks circumstances which sprinkle building plank to appear now, worry these cracks' aring end will cause insecurity trouble, but in succession to building quality direct the section hurl tell.Such as once the some city develop a company to set up 6 layers of floor residence 16 totally, constructing area about 100,000 square meters, the brick mixs structure, the beginning repairs, one steps 2 box off with the brick wall, each one's establishing a turn of beam together building plank is togetherwhole to sprinkle, the plank thick 100 mms, concrete mark number is C20, house long about with 80-90 ms, don't establish flexible sew, first floor is the 2.2 m garage layer, the C20 reinforcing bar cage of the foundation adoption infuses to note a stake.It's small area's turn to complete work in October,2003, finishing construction acceptance, didn't discover obvious crack, discover the building plank appears crackwhen the inhabitant repair, past jointly to quality direct the section hurl tell, through step to see on the spot, 16 houses all exist the depth different crack.The crack width is between the 0.2 mms mms-0.4ses, the great majority of the crack position is placed in plank four Capes, the dynasty sun is more obvious.Hence, the Superintendent office of quality concerned, sinking to decline quantity and inclination degree to carry on a reexamination to the house first, result all in allow the scope, again look into construction diagram paper to also match to request concerning the norm.Owing to above-mentioned circumstance, pass by hard analytical, the confirmation crack reason has the following what time:1. cause now main reason of sprinkling the plank crack is the constringency of concrete, the concrete is in the nature the hardening the process, because water evaporates continuously, but the physical volume gradual constringency, but the plank is on all sides to be subjected to a stipulation of, can't flex freely, so when the constringency of concrete cause to sprinkle knothole stipulation now should the dint exceed certain limit, certanly will cause to sprinkle plank to open crack now.And the crack part take place much at should the dint more concentrated Cape in the place-plank, but is mutually perpendicular with the Overcast angle line of wall2. construct too early on the cast-in-place board , add and carry on one's shoulder or back the crack caused. " norm of inspection of qualityof structural construction of concrete " stipulates , before the concrete intensity reaches 1.2N/mm2, can't trample or install template and support on it . But developer , for race against time , catch up with progress , or concrete at , congeal and congeal stage after all for the first time still in water at the good cast-in-place board just, take up the post of purpose to trample, carry the material , concentrate on piling up fragment of brick , mortar , template ,etc.. Premature adding and is carried on one's shoulder or back, has caused the crack of cast-in-place board artificially.3. the crack which the temperature change causes. As everybody knows, the cement condenses and hardens fast at room temperature, the characteristic such as being great of heat of hydration, especially in summer, after the concrete is built, the release amount of the heat of hydration is great, the concrete is under the high temperature, can't get and water maintenance in time , and desiccate and shrink, make concrete take place dry to split , result in fracturing finally. Investigation find in the majority board corner crack in , tan by the sun towards the front directly the sun.4.the house is crossed too long to set up the essential expansion joint , is the reason which causes the crack too. The developer is in order to save the land, often take the length of the house into account , make the house whole too long, set up expansion joint either, because of lack essential expansion joint, freedom flexible degree in house reach orexceed should set up interval that expansion joint require , will present the crack too.5.the board is defeated by the muscle and sunk in the crack produced . In the course of constructing, because constructors operate barbarously, trample the reinforcing bar arbitrarily , cause and shoulder the muscle and sink, the antiabrasion layer is too big, reduce the sectional effective height of the board, make the bearing capacity of the board unable to reach the requirement of ones that design, thus cause the production of the crack of board.Effective height, make the bearing capacity of the board unable to reach the requirement of ones that design, thus cause the production of the crack of board. How to prevent and cure the production of the board crack of cast-in-place board, according to the construction experience for many years, offer some following prevention measures, suitable for consulting :1. Do well cast-in-place board maintain , work , guarantee concrete intensity , prevent and cure important link that crack produce one of conscientiously. The norm stipulates , must cover and keep maintenance warm in 12 hours after the concrete is built at room temperature, ordinary cement is no less than 7 days, if the one that ignored to concrete watered maintenance, on one hand it reduce concrete intensity, on the other hand it make concrete to be in the course of hardening too late to supplementthe moisture, therefore lack water and produce the crack in a large amount. So do a good job of watering maintenance of concrete , can already reduce the crack that temperature produces , can also reduce the crack that the concrete shrink and produce . 2. cast-in-place board don't pass morning people , pile material , He Shi load , because concrete have a sclerosis course build ,, just have intensity; In this course , should maintain the concrete , can't exert any external force to the concrete . In a situation that the concrete has not had certain intensity yet , concentrate on , pile up construction material or prop up mould stand , rest on it, that brought the cast-in-place board is not intensity like this, but more cracks. So, must make sure that just allow to trample or install template and support on it after the concrete intensity reaches 1.2N/mm2.3. shoulder thickness of antiabrasion layer of the muscle the strict control panel . Cast-in-place board shoulder muscle put , on board , have roof beam according to designing requirement through generally put on reinforcing bar of roof beam or stay with reinforcing bar lashing of roof beam cut off , For control good to shoulder muscle antiabrasion layer thickness , must adopt φ10 - φ14 reinforcing bar horse stool, vertical-horizontal interval 800mm come fixed position to shoulder muscle from side to side, and with electric welding horse with shoulder muscle weld firm stool, make horse to be stool while the concrete builds non-wiping, guarantee , shoulder muscle sink, control , shoulder musclethickness of antiabrasion layer effectively , make board shoulder muscle antiabrasion layer cross thick producing cracking.4. control good sand , stone in a foot-path and mud content strictly. The thick sand in the cast-in-place board should be selected for use, a stone of foot-path between 0.25-0.5mm, the mud content of grit can't exceed 1% . Sand,, stone grains of foot-path careful and too light, mud content too big, will reduce concrete intensity, will make the concrete produce the crack finally.5. dispose certain amounts of angle muscles in four corners of the board , radiate the muscle . Take place in board corner phenomenon this more to cast-in-place board crack, corner set up all around in boardThe length radiates the muscle for about 1800mm, so as to meet demands of angle stress of the board, the stress sphere of action of making the cast-in-place board produce the crack conforms with radiation muscle, thus change and control the production of the crack effectively forced concrete structure reinforced with an overview ReinSince the reform and opening up, with the national economy's rapid and sustained development of a reinforced concrete structure built, reinforced with the development of technology has been great. Therefore, to promote the use of advanced technology reinforced connecting to improve project quality and speed up the pace of construction, improve labor productivity, reduce costs, and is of great significance.Reinforced steel bars connecting technologies can be divided into two broad categories linking welding machinery and steel. There are six types of welding steel welding methods, and some apply to the prefabricated plant, and some apply to the construction site, some of both apply. There are three types of machinery commonly used reinforcement linking method primarily applicable to the construction site. Ways has its own characteristics and different application, and in the continuous development and improvement. In actual production, should be based on specific conditions of work, working environment and technical requirements, the choice of suitable methods to achieve the best overall efficiency.radial squeeze linkWill be a steel sleeve in two sets to the highly-reinforced Department with superhigh pressure hydraulic equipment (squeeze tongs) along steel sleeve radial squeeze steel casing, in squeezing out tongs squeeze pressure role of a steel sleeve plasticity deformation closely integrated with reinforced through reinforced steel sleeve and Wang Liang's Position will be two solid steel bars linkedCharacteristic: Connect intensity to be high, performance reliable, can bear high stress draw and pigeonhole the load and tired load repeatedly.Easy and simple to handle, construction fast, save energy andmaterial, comprehensive economy profitable, this method has been already a large amount of application in the project.Applicable scope : Suitable for Ⅱ, Ⅲ, Ⅳgrade reinforcing bar (including welding bad reinforcing bar ) with ribbing of φ18- 50mm, connection between the same diameter or different diameters reinforcing bar .must squeeze linkExtruders used in the covers, reinforced axis along the cold metal sleeve squeeze dedicated to insert sleeve Lane two hot rolling steel drums into a highly integrated mechanical linking methods.Characteristic: Easy to operate and joining fast and not having flame homework , can construct for 24 hours , save a large number of reinforcing bars and energy.Applicable scope : Suitable for , set up according to first and second class antidetonation requirement -proof armored concrete structure φⅡ, Ⅲgrade reinforcing bar with ribbing of hot rolling of 20- 32mm join and construct live.cone thread connectingUsing cone thread to bear pulled, pressed both effort and self-locking nature, undergo good principles will be reinforced by linking into cone-processing thread at the moment the value of integration into the joints connecting steel bars.Characteristic: Simple , all right preparatory cut of the craft , connecting fast, concentricity is good, have pattern person who restrain from advantage reinforcing bar carbon content.Applicable scope : Suitable for the concrete structure of the industry , civil building and general structures, reinforcing bar diameter is for for the the 16- 40mm one Ⅱ, Ⅲgrade verticality, it is the oblique to or reinforcing bars horizontal join construct live.These are now commonly used to connect steel synthesis methods, which links technology in the United States, Britain, Japan and other countries are widely used. There are different ways to connect their different characteristics and scope of the actual construction of production depending on the specific project choose a suitable method of connecting to achieve both energy conservation and saving time limit for a project ends.Causes of cracks in concrete and control measuresShrinkage cracksShrinkage cracks are caused by the humidity, it accounts for non-structural cracks in concrete in the main part. We know that concrete is a cement as the main cementing material to natural sand, stone aggregate mixing water, after casting molding, hardens and the formation of artificial stone.In the construction, in order to ensure its workability, often adding cement hydration than water needed for 4 to 5 times more water. More of these water to free state exists, and the gradualevaporation of the hardening process, resulting in the formation of large pores inside the concrete, voids or holes, resulting in volume shrinkage of concrete. In addition, the hardening process of concrete hydration and carbonation of concrete volume will lead to shrinkage. According to the experimental determination of the ultimate shrinkage of concrete is about 0104% ~ 0106%.Shows that shrinkage is the inherent physical properties of concrete, in general, the larger water-cement ratio, the higher the concrete strength, aggregate less, the higher the temperature, surface water loss is larger, the larger the value of its contract, the more easily shrinkage cracks. According to the formation of shrinkage cracks and formation mechanism of the time, works in the common shrinkage cracks are mainly plastic shrinkage cracks, settlement shrinkage cracking and drying shrinkage cracks in three categories, in addition to their contract (chemical shrinkage) cracks and carbonation shrinkage cracks.Plastic shrinkage cracks Plastic shrinkage cracks in concrete plastic stage, before the final set. The cause of this is concrete paste and quickly evaporating water flow to the surface, with the increase in water loss, capillary negative pressure generated by contraction of the concrete surface of the drastic volume shrinkage. Strength of concrete at a time has not yet formed, which resulted in cracking of the concrete surface.This multi-cracks in dry weather, hot and windy, the fracture shallow, intermediate width, both ends of the fine, of different lengths, anddisconnected.中文译文现浇楼板裂缝的产生与防治Rothbard M随着城镇住宅建设步伐的加快，不少小区居住区相继成立，不少居民不断迁入新居，其对住房要求的质量越来越高，尤其是要重视现在一些散落的建筑板出现裂缝的情况，担心这些裂缝的坍塌会造成不安全的麻烦，但相继对建筑质量直接段投诉。
土木工程混凝土论文中英文资料外文翻译文献
土木工程混凝土论文中英文资料外文翻译文献外文资料STUDIES ON IMPACT STRENGTH OF CONCRETESUBJECTED TO SUSTAINEDELEVATED TEMPERATUREConcrete has a remarkable fire resisting properties. Damage in concrete due to fire depends on a great extent on the intensity and duration of fire. Spalling cracking during heating are common concrete behaviour observed in the investigation of the fire affected structures. Plenty of literature is available on the studies of concrete based on time temperature cures. In power, oil sectorsand nuclear reactors concrete is exposed to high temperature for considerable period of time. These effects can be reckoned as exposure to sustained elevated temperature. The sustained elevated temperature may be varying from a few hours to a number of years depending upon practical condition of exposures. The knowledge on properties under such conditions is also of prime importance apart from the structures subjected to high intensity fire. Impact studies of structure subjected to sustained elevated temperature becomes more important as it involves sensitive structures which is more prone to attacks and accidents. In this paper impact studies on concrete subjected to sustained elevated temperature has been discussed. Experiments have been conducted on 180 specimens along with 180 companion cube specimens. The temperatures of 100°C, 200°C and 300°C for a duration of exposure of 2 hours 4 hours and 6 hours has been considered in the experiments. The results are logically analyzed and concluded.1. INTRODUCTIONThe remarkable property of concrete to resist the fire reduces the damage in a concrete structure whenever there is an accidental fire. In most of the cases the concrete remains intact with minor damages only. The reason being low thermal conductivity of concrete at higher temperatures and hence limiting the depth of penetration of firedamage. But when the concrete is subjected to high temperature for long duration the deterioration of concrete takes place. Hence it is essential to understand the strength and deformation characteristics of concrete subjected to temperature for long duration. In this paper an attempt has been made to study the variation in Impact Strength of concrete when subjected to a temperature range 100oC, 200oC and 300oC sustained for a period of 2 hrs, 4 hrs and 6 hrs.The review of the literature shows that a lot of research work [1 – 3] has taken place on the effect of elevated temperature on concrete. All these studies are based on time –temperature curves. Hence an attempt has been made to study the effect of sustained elevated temperature on impact strength of concrete and the results are compared with the compressive strength. The experimental programme has been planned for unstressed residual strength test based on the available facilities. Residual strength is the strength of heated and subsequently cooled concrete specimens expressed as percentage of the strength of unheated specimens.2. EXPERIMENTAL INVESTIGATION2.1. TEST SPECIMEN AND MATERIALSA total of 180 specimens were tested in the present study along with 180 companion cubes. An electric oven capable of reaching a maximum temperature of 300oC has been used for investigation. Fine and coarse aggregates conforming to IS383 has been used to prepare the specimen with mix proportions M1 = 1:2.1:3.95 w/c = 0.58, M2 = 1:1.15:3.56 w/c = 0.53, M3 = 1:0.8:2.4 w/c = 0.4.2.2 TEST VARIABLESThe effects of the following variables were studied.2.2.1 Size sSize of Impact Strength Test Specimen was 150 mm dial and 64 mm thickness and size of companion cube 150 x 150 x 150 mm.2.2.2 Maximum TemperatureIn addition to room temperature, the effect of three different temperatures (100oC, 200oC and 300oC) on the compressive strength was investigated.2.2.3 Exposure Time at Maximum TemperatureThree different exposure times were used to investigate the influence of heat on compressive strength; they are 2 hrs, 4 hrs and 6 hrs.2.2.4 Cooling MethodSpecimens were cooled in air to room temperature.3. TEST PROCEDUREAll the specimens were cast in steel moulds as per IS516 and each layer was compacted. Specimens were then kept in their moulds for 24 hours after which they were decoupled and placed into a curing tank until 28 days. After which the specimens were removed and were allowed to dry in room temperature. These specimens were kept in the oven and the required target temperature was set. Depending on the number of specimen kept inside the oven the time taken to reach the steady state was found to vary. After the steady state was reached the specimens were subjected to predetermined steady duration at the end of which the specimens are cooled to room temperature and tested.ACI drop weight impact strength test was adopted. This is the simplest method for evaluating impact resistance of concrete. The size of the specimen is 150 mm dial and 64 mm thickness. The disc specimens were prepared using steel moulds cured and heated and cooled as. This consists of a standard manually operated 4.54 kg hammer with 457 mm drop. A 64 mm hardened steel ball and a flat base plate with positioning bracket and lugs. The specimen is placed between the four guides pieces (lugs) located 4.8 mm away from the sample. A frame (positioning bracket) is then built in order to target the steel ball at the centre of concrete disc. The disc is coated at the bottom with a thin layer of petroleum jelly or heavy grease to reduce the friction between the specimen and base plate. The bottom part of the hammer unit was placed with its base upon the steel ball and the load was applied by dropping weight repeatedly. The loading was continued until the disc failed and opened up such that it touched three of the four positioning lugs. The number of blows that caused this condition is recorded as the failure strength. The companion cubes were tested for cube compression strength (fake).4. ANALYSIS AND RESULTS4.1 RESIDUAL COMPRESSIVE STRENGTH VS. TEMPERATUREFrom Table 1, at 100°C sustained elevated temperature it is seen that the residual strength of air cooled specimens of mixes M1, M2 and M3 has increased in strength 114% for M1 mix, 109% for M2 mix and 111% for M3 mix for 6 hours duration of exposure. When the sustained elevated temperature is to 200°C for air cooled specimens there is a decrease in strength up to 910% approximately for M1 mix for a duration of 6 hours, but in case of M2 mix it is 82% and for M3 mix it is 63% maximum for 6 hours duration of exposure. When the concrete mixes M1, M2 and M3 are exposed to 300°C sustained temperature there is a reduction in strength up to 78% for M1 mix for 6 hour duration of exposure.4.2 RESIDUAL COMPRESSIVE STRENGTH VS DURATION OF EXPOSUREFrom Table 1, result shows that heating up to 100°C for 2 hours and 4 hours, the residual strength of mix M1 has decreased where as the residual strength of mix M2 and M3 has increased. The residual strength is further increased for 6 hours duration of exposure in all the three mixes M1, M2 and M3 even beyond the strength at room temperature. When the specimens of mixes M1, M2 and M3 are exposed to 200°C for 2,4 and 6 hours of duration, it is observed that the residual strength has decreased below the room temperature and has reached 92% for M1 mix, 82 and 73% for M2 and M3 mix respectively. Concrete cubes of mixes M1, M2 and M3 when subjected to 300°C temperature for 2,4 and 6 hours the residual strength for mix M1 reduces to 92% for 2 hours up to 78% for six hours duration of exposure, for M2 mix 90% for 2 hours duration of exposure up to 76% for six hour duration of exposure, for M3 mix 88% up to 68% between 2 and 6 hours of duration of exposure.5. IMPACT STRENGTH OF CONCRETE5.1 RESIDUAL IMPACT STRENGTH VS TEMPERATUREFrom the table 1, it can be observed that for the sustained elevated temperature of 100°C the residual impact strength of all the specimens reduces and vary between 20 and 50% for mix M1, 15 to 40% for mix M2 and M3. When the sustained elevated temperature is 200°C the residual impact strength of all the mixes further decreases. The reduction is around 60-70% for mix M1, 55 to 65% for M2 and M3 mix. When the sustained elevated temperature is 300°C it is observed that the residual impact strength reduces further and vary between 85 and 70% for mix M1 and 85 to 90% for mix M2 and mix M3.5.2 RESIDUAL IMPACT STRENGTH VS DURATION OF EXPOSUREFrom the Table 1 and Figures 1 to 3, it can be observed that there is a reduction in impact strength when the sustained elevated temperature is 100°C for 2 hrs, 4 hrs and 6 hrs, and its range is 15 to 50% for all the mixes M1, M2 and M3. The influence of duration of exposure is higher for mix M1 which decreases more rapidly as compared to mix M2 and mix M3 for the same duration of exposure. When the specimens are subjected to sustained elevated temperature of 200°C for 2,4 and 6 hour of duration, further reduction in residual impact strength is observed as compared to at 100°C. The reduction is in the range of 55-70% for all the mixes. The six hour duration of exposure has a greater influence on the residual impact strength of concrete. When the sustained elevated temperature is 300°C for 2,4 and 6 hours duration of exposure the residualimpact strength reduces. It can be seen that both temperature and duration of exposure have a very high influence on the residual impact strength of concrete which shows a reduction up to 90% approximately for all the mixes.6. CONCLUSIONThe compressive strength of concrete increases at 100oC when exposed to sustained elevated temperature. The compressive strength of concrete decreases when exposed to 200°C and 300°C from 10 to 30% for 6 hours of exposure. Residual impact strength reduces irrespective of temperature and duration. Residual impact strength decreases at a higher rate of 20% to 85% as compared to compressive strength between 15% and 30 % when subjected to sustained elevated temperature. The impact strength reduces at a higher rate as compared to compressive strength when subjected to sustained elevated temperature.混凝土受持续高温影响的强度的研究混凝土具有显着的耐火性能。
毕业论文外文翻译-建筑施工混凝土开裂预防加工
毕业论文外文翻译-建筑施工混凝土开裂预防加工Prevention and Treatment of Concrete Cracks in Building ConstructionAbstract：Concrete is widely used in building construction because of its advantages such as durability, strength and low maintenance cost. However, concrete cracks can not only affect the aesthetic appearance of buildings, but also have negative impact on structural integrity and durability. This paper focuses on the prevention and treatment of concrete cracks in building construction. Firstly, the causes of concrete cracking are analyzed, including shrinkage, thermal stress, structural design, material quality and construction quality. Then, preventive measures in design and construction are proposed, such as proper reinforcement arrangement, control of concrete mix proportions, proper curing and protection after pouring, etc. Treatment measures for existing concrete cracks include surface treatment, filling and injection, and reinforcement. Finally, some new techniques are briefly introduced, such as fiber-reinforced concrete, self-healing concrete and material testing technology. This paper provides a comprehensive understanding of the prevention and treatment of concrete cracks in building construction, and proposes practical solutions to improve the quality of concrete structures.Key words: concrete cracks; building construction; prevention; treatmentIntroduction：Concrete is a popular building material due to its properties such as durability, strength and low maintenance cost. However, concrete cracking is a common problem in building construction, which can not only affect the aesthetic appearance of buildings, but also have negative impact on structural integrity and durability. Therefore, preventing and treating concrete cracks are crucial to ensure the long-term performance of buildings. This paper analyzes the causes of concrete cracking in building construction, and proposes preventive and treatment measures based on practical experience and research.1. Causes of Concrete Cracking：1.1 ShrinkageShrinkage is the most common cause of concrete cracking, which is due to the decrease in volume of concrete as it dries and hardens. Shrinkage can be classified into autogenous shrinkage, plastic shrinkage and drying shrinkage.Autogenous shrinkage is caused by the chemical reaction between water and cement, and it can lead to micro-cracks. Plastic shrinkage is caused by the evaporation of water from the surface of fresh concrete, which can cause cracks in the surface layer. Drying shrinkage is caused by the loss of moisture from the hardened concrete, which can lead to cracks in the bulk of the structure.1.2 Thermal StressThermal stress is another cause of concrete cracking, which is due to the temperature difference between the interior and exterior of concrete. When the temperature change is rapid or large, thermal stress can exceed the tensile strength of concrete and cause cracking.1.3 Structural DesignPoor structural design can also cause concrete cracking. For example, inadequate reinforcement or improper placement of reinforcement can lead to excessive stress concentration and cracking. In addition, insufficient structural support or improper joint design can also cause concrete cracking.1.4 Material QualityThe quality of concrete materials such as cement, aggregates and water can also affect concrete cracking. Poor quality materials can result in uneven shrinkage, low strength, and high water permeability, which can cause cracking.1.5 Construction QualityConstruction quality is an important factor in the prevention of concrete cracking. Improper placement, compaction and curing of concrete can lead to poor quality, which can cause cracking. In addition, inadequate protection measures such as insufficient cover or damage to the surface layer can also cause cracking.2. Prevention of Concrete Cracking：2.1 Reinforcement ArrangementProper reinforcement arrangement is essential to prevent concrete cracking. The size, spacing and distribution of reinforcement should be designed according to the structural requirements and the characteristics of concrete. In addition, the use of fiber reinforcement can improve the crack resistance of concrete.2.2 Control of Concrete Mix ProportionsThe control of concrete mix proportions is critical to the prevention of concrete cracking. The ratio of water to cement, the type and quality of aggregates, and the use of admixtures should be carefully considered to ensure proper workability and strength of concrete.2.3 Proper Curing and ProtectionProper curing and protection measures can effectively prevent concrete cracking. Adequate moist curing can reduce evaporation and shrinkage, and increase strength and durability. In addition, proper protection measures such as sufficient cover and protective coatings can protect the surface layer of concrete from damage.3. Treatment of Concrete Cracks：3.1 Surface TreatmentSurface treatment is a common method to repair concrete cracks. The damaged concrete is removed, and the surface is cleaned and roughened. Then, a bonding agent is applied and a new layer of concrete is poured to fill the crack.3.2 Filling and InjectionFilling and injection is another effective method to repair concrete cracks. The crack is filled with cementitious material, such as epoxy or polymer, to restore theintegrity of the structure. Injection is also used to repair cracks in reinforced concrete structures, where the material is injected under pressure to fill the voids and cracks.3.3 ReinforcementReinforcement is used when the crack is severe and structural integrity is compromised. Steel bars or plates are installed into the crack and bonded to the surrounding concrete to restore the strength and load-carrying capacity of the structure.4. New Techniques：4.1 Fiber-Reinforced ConcreteFiber-reinforced concrete is a new type of concrete that contains short fibers, such as glass, steel or synthetic fibers, which can improve the crack resistance and toughness of concrete.4.2 Self-Healing ConcreteSelf-healing concrete is a novel material that can repair micro-cracks by itself through the chemical reaction between water and the embedded capsules.4.3 Material Testing TechnologyMaterial testing technology such as acoustic emission and electrical resistance can effectively detect and monitor the formation and propagation of cracks in concrete structures, and provide early warning for potential failures.Conclusion：Concrete cracking is a common problem in building construction, which can affect the aesthetic appearance, structural integrity and durability of buildings. This paper analyzes the causes of concrete cracking, and proposes practical preventive and treatment measures to improve the quality of concrete structures. In addition, some new techniques such as fiber-reinforced concrete, self-healing concrete andmaterial testing technology are briefly introduced. With proper design, construction and maintenance, the occurrence and impact of concrete cracking can be effectively reduced, and the long-term performance of concrete structures can be ensured.。
外文翻译混凝土裂缝的成因预防及处理
The causes, prevention and treatment of cracks in concrete Abstract:In the building construction concrete cracks a quality common problem, the causes of cracks in concrete, prior prevention, as well as after the repair process is a more common phenomenon in the process of building production, should be taken seriously enough. The concrete is a brittle material of a gravel aggregate, cement, water and other additional material formed by mixing a non-homogeneous. Concrete construction and deformation constraints and a series of problems, there are a large number of micro-porosity, cavitation and micro-cracks in the concrete hardening molding. The author combines his engineering work experience, summed up the cracks in concrete causes and prevention measures.Keywords: causes of cracks in concrete preventive treatmentIn building construction, concrete cracks is a widespread problem, cracks solution is a more difficult problem. Cracks in concrete reasons are manifold, deformation: such as contraction, expansion, settlement and other causes cracks; external load caused by: improper maintenance of concrete; cracks caused by the external additive problems.Concrete cracks, if not prevention measures to solve, extending its further development will lead to the internal reinforcement corrosive, reducing the carrying capacity of the reinforced concrete structure, impermeability, durability useful life, and even affect people's lives and property safety . Crack is impossible to completely eliminate the engineering specification expressly provides some structure in which the different conditions, allowing the existence of a certain width and depth of the crack. But in the construction process should be as far as possible to take effective preventive and technical safeguards to effectively control the cracks, as little as possible or minimize crack width, depth, and in particular to avoid in key positions or harmful cracks.1.Causes and types of concrete cracksThe concrete is a brittle material of a gravel aggregate, cement, water and other additional material formed by mixing a non-homogeneous. Hardening molding concrete concrete construction and deformation constraints there are a large number of micro-porosity, cavitation and micro-cracks, precisely because of the existence of these initial defects before the concrete showing some heterogeneity characteristics . Micro-cracks is usually a harmless cracks on concrete load-bearing, seepage and use the function does not cause harm. But in the concrete under load, temperature effects, the micro-cracks will continue to expand and connectivity, and ultimately the formation of visible macro cracks, the cracks is often said that the concrete works.Many cracks in concrete cracks caused by deformation: such as temperature change, shrinkage, expansion, uneven subsidence caused cracks; external load induced cracks; cracks caused by improper conservation of the environment and chemical action, etc. .Common cracks in the concrete are the following: (1) shrinkage cracks; ②plastic shrinkage cracking; (3) settlement cracks; ④temperature cracks; ⑤chemical reaction caused by cracks.2.Concrete cracks and prevention2.1 Shrinkage cracks and prevention ofShrinkage cracks appear in a week or so after the end of the concrete curing period of time or after concrete pouring. The evaporation of the water in the slurry will produce shrinkage, and the shrinkage is irreversible. Drying shrinkage cracks are mainly caused due to the different degree of evaporation of the moisture inside and outside the concrete result of deformation of the type: concrete affected by the influence of external conditions, excessive surface moisture loss, large deformation, internal humidity changes smaller deformation smaller, the larger the surface shrinkage deformation by concrete internal constraints, have a greater tensile stress cracks. The lower the relative humidity, the greater the shrinkage of cement paste shrinkage cracks are easy to produce. Shrinkage cracks parallel to the surface of the linear or reticular light fine cracks, width of more than 0.05 to 0.2 mm between the flat parts more common in mass concrete, thin flat-slab along the short to distribution. Shrinkage cracks usually affect the impermeability of concrete, causing corrosion of steel affect the durability of concrete, water pressure will produce hydraulic fracturing affecting concrete bearing capacity. The concrete shrinkage main and to the water-cement ratio of the concrete, cement component, the amount of cement used, thenature and amount of aggregate, the amount of admixture.The main preventive measures:(1)Selection of a smaller amount of shrinkage cement, commonly used in low heat cement and fly ash cement, reduce the amount of cement.(2)Concrete shrinkage by water-cement ratio, the greater the water-cement ratio, the greater the shrinkage in the concrete mix design should try to control the selection of a good water-cement ratio, while mixing the water-reducing agent .(3)Strict control than with concrete mixing and construction, concrete water consumption must not be greater than the amount of water given by the mixture ratio design.(4)To strengthen the early curing of concrete and appropriate to extend the concrete curing time. Appropriate to extend the winter construction concrete insulation cover, and brushing curing agent curing.(5) Set the appropriate contraction joints in concrete structures2.2 Plastic shrinkage cracks and preventionThe plastic shrinkage refers to the before condensation, the concrete surface due to rapid dehydration resulting contraction. Plastic shrinkage cracking is generally hot and dry or windy weather, the cracks mostly wide in the middle, both ends of the thin and vary in length, non-coherentstate. Short cracks as long as 20 to 30cm the longer cracks of up to 2 to 3 m, width of 1 to 5 mm. Main causes: the concrete before the final setting almost no strength or intensity is very small or just the final setting concrete small strength, high temperature or a larger wind, the concrete surface excessive water loss, resulting in capillary have a greater negative pressure of the concrete volume of a sharp contraction, but this time the strength of the concrete can not resist its own contraction, resulting in cracking. The main factors affecting the plastic shrinkage cracking water-cement ratio, the setting time of the concrete, the ambient temperature, wind speed, relative humidity, and so on.The main preventive measures:(1) Selection of shrinkage values smaller high early strength Portland cement or ordinary Portland cement.(2) Strict control of water-cement ratio, to increase the slump and workability of the concrete, to reduce the amount of cement and water mixed with superplasticizer.(3) Pouring concrete before watering the grass roots and templates evenly soaked.(4) Timely covered by plastic film or wet straw, hemp sheet to maintain final setting of concrete the moist front surface or the surface of the concrete spraying curing agent for conservation.To set the sun and wind facilities .(5) At high temperatures and windy weather, timely conservation.2.3 subsidence cracks and preventionSubsidence cracks caused by structural foundation soil is uneven, soft, or backfill or flooding due to uneven settlement; template stiffness, the template support spacing is too large or the bottom of the support as a result of loose, especially in the template support winter on the frozen ground, permafrost thaw uneven settlement, resulting in the concrete structure cracks. Such cracks are deep into or through the cracks, toward subsidence, generally along the perpendicular to the ground or in the form of an angle of 30 °to 45 °direction, subsidence cracks tend to have a certain amount of dislocation, crack width is often and is proportional to the amount of the settlement. Crack width was less affected by temperature changes. Ground deformation stability, subsidence cracks basically stabilized.The main preventive measures:(1)on the soft soil, filling foundation should be carried out prior to the construction of the superstructure necessary compaction and reinforcement.(2)to ensure that the template has a sufficient strength and stiffness, and firmly support the foundation uniform force.(3) prevent the process of concreting the foundation is immersed inwater.(4) template removal time can not be too early, and pay attention to the order form removal.(5) in the erection of the template on the permafrost to take certain precautions.2.4 Temperature cracks and preventionTemperature cracks occurred in mass concrete surface or larger changes in temperature regions in concrete structures. Concrete pouring, in the hardening process of cement hydration reaction to produce large amounts of heat of hydration (when the amount of cement per cubic meter of concrete will release 17,500 27500kJ heat at 350 to 550 kg/m3, so that the internal temperature of the concrete SITA about 70 °C or higher). Cause the internal temperature to rise sharply due to the larger volume of concrete, the accumulation of a large amount of heat of hydration within the concrete and easy to distribute, and rapid cooling of the surface of the concrete, thus forming a larger temperature difference inside and outside, the larger the temperature difference caused by the internal and external different degrees of thermal expansion and contraction of the concrete surface tensile stress (Practice has proved that when the temperature difference between inside and outside of the concrete itself is 25 ° C to 26 °C, will produce roughly about10MPa concrete tensile stress). When the tensile stress exceeds the ultimate tensile strength of the concrete, the concrete surface cracks, cracks occurred in the concrete construction in the late. Concrete construction when the temperature changes, or concrete attacked by the cold wave will lead to concrete surface temperature sharp decline, and contraction, contraction of the concrete surface bound by internal concrete, will produce large tensile stress. cracks, such cracks are generated in the the shallow concrete surface within the range of usually only.The trend of temperature cracks usually certain rules, often criss-cross a large area of structural cracks; the length of the beam and plate size larger structures, cracks parallel to the short side; deep and penetrating temperature cracks are generally parallel or nearly parallel to the direction of the short side , cracks along the longest edge segments appear more dense middle. Crack width sizes, affected by temperature changes more obvious, summer, winter wide narrow. The high temperature expansion caused by the concrete temperature is usually middle coarse fine at both ends, while the the shrink cracks thickness less obvious changes. The emergence of such cracks can cause corrosion of steel, concrete carbonation, reduce freeze-thaw resistance of concrete, anti-fatigue and impermeability.The main preventive measures:(1) try to use low heat or moderate heat cement, slag cement, fly ash cement.(2) reduce the amount of cement to try to control the amount of cement 450kg/m3.(3) reduce the water-cement ratio, generally water-cement ratio of concrete is controlled below 0.6.(4) improve the aggregate gradation, fly ash or superplasticizer to reduce the amount of cement, lower heat of hydration.(5) improve the concrete mixing process, "secondary air" traditional "cold" on the basis of new technology, reduce the temperature of concrete pouring.(6)a certain amount of concrete admixture having less water, plasticizers, retarding admixture role to improve the fluidity of the concrete mixture, water retention, reduce the heat of hydration, delaying the time of occurrence of the thermal peak.(7)hot season puts up visor and other auxiliary measures to control the temperature rise of the concrete pouring, to reduce pouring concrete temperature.(8)mass concrete temperature stress associated with the structure size, the larger the size of the concrete structure, the greater the temperature stress, so reasonable arrangements for the construction process, hierarchical, block pouring, to facilitate cooling, reducingconstraints.2.5 chemical reaction caused cracks and preventionAlkali-aggregate reaction cracks and steel corrosion cracks caused by the most common due to the chemical reaction caused by cracks in the reinforced concrete structure. Concrete mixing will produce some of the alkaline ions, these ions produce a chemical reaction with certain reactive aggregate and absorbs water in the surrounding environment and the volume increases, resulting in concrete crisp, expansion cracking. Such cracks usually appear in the concrete structure during use, in the event difficult to remedy, should take effective measures to prevent it in the construction. Concrete pouring poor vibrators or reinforced protective layer is thin, harmful substances into the concrete reinforcing bars from corrosion, the corroded reinforcement volume expansion, leading to concrete Splitting the cracks of this type of longitudinal cracks along the location of reinforcement .The main preventive measures:(1) selection of the alkali reactivity of small sand and gravel aggregate.(2) selection of low-alkali cement and admixtures of low-alkali or alkali.(3) selection of a suitable admixture AAR with.3 crack treatmentCracks in concrete remedial measures mainly the following methods: surface repair method, grouting, caulking closure method, structural reinforcement, concrete replacement method, electrochemical protection and legal bionic self-healing.3.1 Surface repair methodSurface repair method is a simple, common repair method, the action is in the cracks in the surface of the painting grout, epoxy mortar or concrete surface coating paint, anti-corrosion materials such as asphalt, concrete protection at the same time in order to prevent various The Effect of cracking, usually can paste in cracks in the surface of the glass fiber cloth and other measures.3.2 grouting, caulking closure methodThe grouting method is the use of pressure equipment cementing material is pressed into the cracks in the concrete, the cementing material hardened concrete to form a whole, and thus play the purpose of plugging consolidation. Top cementing material grout, epoxy, methacrylate, polyurethane and other chemical materials. The filleting gouges along the cracks in the tank filled, the plastic or rigid sealing material, in order to achieve the purpose of closed cracks. Commonly used plastic materialsare PVC, clay, plastic ointment, butyl rubber, etc.; rigid sealing material is a polymer cement mortar.3.3 Structural reinforcement methodWhen the the cracks impact on the performance of concrete structures, to take structural reinforcement concrete structure. Commonly used in the following ways: structural reinforcement to increase the cross-sectional area of the concrete structure, corner in the component outsourcing steel, prestressed Reinforcing paste the steel reinforcement, additional the fulcrum reinforcement and shotcrete reinforcement.3.4 Concrete replacement methodThe concrete substitution method is an effective method for dealing with serious damage to the concrete, this method is deteriorated concrete is removed first, and then replaced into the new concrete or other materials. Top replacement materials: of Ordinary concrete or cement mortar, polymer or polymer modified concrete or mortar.3.5 electrochemical Protection ActCathodic protection, chloride extraction, alkaline recovery method, the use of the electrochemical action of the applied electric field in the medium, to change concrete or reinforced concrete in which the state of the environment, passivated steel, in order to achieve the purpose ofanti-corrosion.3.6 biomimetic self-healing legalBionic self-healing legitimate the traditional components of the concrete in some special components such as liquid-core fibers or capsules containing binder, formed within the concrete the intelligent bionic self-healing neural network system, when the concrete cracks secreted part of the liquid core fiber cracks can heal again. Conclusion:Cracks is a common phenomenon in the concrete structure, its appearance will not only reduce the impermeability of the building, affect the use of the building, and would lead to corrosion of steel, concrete carbonation, reduce the durability of the materials, the impact the carrying capacity of the building, so to carefully study the concrete cracks, be treated differently, using a reasonable method for processing to take effective preventive measures to prevent the emergence and development of cracks in the construction, to ensure the safety of buildings and structures and stable work.混凝土裂缝的成因、预防及处理摘要：在建筑工程施工中混凝土裂缝的产生是一项质量通病，因此对混凝土裂缝的成因分析、事先预防，以及产生后的修补处理是建筑生产过程中较为普遍的现象，应引起足够的重视。
混凝土裂缝中英文对照外文翻译文献
中英文资料对照外文翻译Causes and control measures of concrete cracks study the problemKeywords: Causes prevention of concrete cracksAbstract: At present, paid close attention to the problem of concrete cracks, this crack in the concrete on the basis of classification, analysis of the causes of different cracks, and proposed measures to crack prevention and treatment.1.IntroductionIs the maximum amount of concrete as a building material, widely used in industrial and civil construction, agriculture and forestry with urban construction, water conservancy works in the harbor. However, many concrete structures occurs during the construction and use of different degrees and different forms of fracture. This not only affects the appearance of the building, but also endanger the normal use of buildings and structures durability.Therefore, the cracks become people concerns. In recent years, with the ready-mixed concrete and vigorously promote the use and structure become increasingly large, complex, making the problem even more prominent.However, cracks in concrete structures is a fairly common phenomenon, large number of engineering practice and modern science on the concrete strength of micro studies show that the structures of the crack is inevitable, which is a property of the material. Therefore, the scientific treatment of cracks in the crack problem is to classify on the basis, adopt effective measures to harmful levels of crack control to the extent permitted. This concrete structure will cause cracks in common, control measures and the repair method to analyze some light.2.Classification of concrete cracks2.1 Divided by Crack According to the causes of concrete cracks, structural cracks and can be divided into two major categories of non-structural cracks.(1) Structural cracks Caused by a variety of external loads cracks, also called load cracks. It includes the external loads caused by the direct stress cracks and the structure under external loads caused by secondary stress cracks.(2) Non-structural cracks Deformation caused by the change from a variety of cracks. It includes temperature, shrinkage and swelling caused by factors such as differential settlement cracks. Such cracks in the structure when the deformation is restricted due to the stress caused. Research data from abroad and a large number of engineering practice, non-structural cracks in the works in the majority, about 80%, which led to shrinkage cracks.2.2Divided by the time the cracks(1)Cracks during construction Including plastic shrinkage cracks, settlement shrinkage cracking, drying shrinkage cracks, shrinkage cracks itself, the temperature cracks, the cracks were improper construction operations, the role of early frost, and some irregular cracks caused by cracks.(2)Use of crack during Including the expansion of steel corrosion cracks generated, salt and acid erosion type liquid medium caused by cracks, the cracks caused by freezing and thawing, alkali aggregate reaction, and cracks caused by cyclic loading cumulative damage caused by cracks.2.3Classification of fractured by cracks in the shape of the shape can be divided by:(1)Longitudinal cracks parallel to the bottom component, the distribution along tendons, mainly caused by the role of steel corrosion(2)Transverse cracks perpendicular to the bottom component mainly by the loading, temperature effects caused(3)Shear cracks due to displacement caused by vertical load or vibration(4)Diagonal cracks eight shaped or herringbone cracks, common in the wall of concrete beams, mainly due to the uneven foundation settlement, and thermal effects caused by(5)X-shaped cracks common in the framework of beams, columns and walls on the ends, due to the impact effect, or moment loads caused by earthquake(6)All kinds of irregular cracks such as repeated freezing and thawing, or fires caused by cracksIn addition, concrete mixing and transport time for long cracks due to mesh, squareappears floor slab or plate surface radial cracks appear in the cross cracks and so on.2.4 The development of the state divided by cracksAccording to fracture the movement in which the state and development trends, can be divided into the following categories:(1)Stable crack This crack does not affect the persistence of applications, including two types.One is in motion the process of self-healing of fractures could be common in a number of new water projects, this is because the crack of cement particles in the leakage of water further compounds the process, precipitate Ca (OH) 2 crystal and part of the Ca ( OH) 2 has dissolved in the water with CO2 carbonation reaction to form CaCO3 crystallization occurs, both the formation of cracks in the gel material will be glued closed, and thus stop the leakage, cracks to heal. The other is in a stable movement of the cracks, such as the periodic load generated by the cyclical expansion and closure of cracks.(2)Unstable crack This will result in instability of crack extension, affecting the sustainable use of structures, should be considered part of its expansion, to take corresponding measures.3.Causes of cracks in concrete and control measures3.1 Shrinkage cracks Shrinkage cracks are caused by the humidity, it accounts for non-structural cracks in concrete in the main part. We know that concrete is a cement as the main cementing material to natural sand, stone aggregate mixing water, after casting molding, hardens and the formation of artificial stone.In the construction, in order to ensure its workability, often adding cement hydration than water needed for 4 to 5 times more water. More of these water to free state exists, and the gradual evaporation of the hardening process, resulting in the formation of large pores inside the concrete, voids or holes, resulting in volume shrinkage of concrete. In addition, the hardening process of concrete hydration and carbonation of concrete volume will lead to shrinkage. According to the experimental determination of the ultimate shrinkage of concrete is about 0104% ~ 0106%.Shows that shrinkage is the inherent physical properties of concrete, in general, the larger water-cement ratio, the higher the concrete strength, aggregate less, the higher the temperature, surface water loss is larger, the larger the value of its contract, the more easily shrinkage cracks. According to the formation of shrinkage cracks and formation mechanism of the time, works in the common shrinkage cracksare mainly plastic shrinkage cracks, settlement shrinkage cracking and drying shrinkage cracks in three categories, in addition to their contract (chemical shrinkage) cracks and carbonation shrinkage cracks.3.1.1Plastic shrinkage cracks Plastic shrinkage cracks in concrete plastic stage, before the final set. The cause of this is concrete paste and quickly evaporating water flow to the surface, with the increase in water loss, capillary negative pressure generated by contraction of the concrete surface of the drastic volume shrinkage. Strength of concrete at a time has not yet formed, which resulted in cracking of the concrete surface.This multi-cracks in dry weather, hot and windy, the fracture shallow, intermediate width, both ends of the fine, of different lengths, and disconnected.3.1.2 Settlement shrinkage cracking Settlement shrinkage cracks in concrete pouring about half an hour after the occurrence and hardening stops. The cause of this is occurring after the slurry in the Pouring uneven sink, sinking of coarse aggregate, cement grout float, when the settlement was inhibited (such as steel or embedded parts of the block) is due to shearing and cracking of the concrete. In addition, floating in the plasma layer formed on the surface will be a result of bleeding and cracking.This multi-cracks in the concrete surface, and pass along the long direction of the reinforcement, or the stirrups the distribution width of both ends of the narrow middle, is a common early cracks, especially in the pump construction is more common.3.1.3 Drying shrinkage cracks Drying shrinkage cracks in the concrete curing only appeared after completion. Its formation was mainly due to the concrete to harden, the water evaporation caused by shrinkage of the concrete surface, when the shrinkage deformation of concrete by internal constraint, have a greater tensile stress to crack the concrete surface is pulled.Shrinkage cracks on the surface generally produces very shallow location, multi-component along the short direction of distribution, were parallel, linear, or mesh, can be severe throughout the member section.3.1.4 Self-shrinkage cracks Shrinkage cracks itself has nothing to do with the outside humidity, but because of the hydration reaction of cement clinker in the process, the reaction resultant of the average density of smaller volume shrinkage caused by system (called chemical shrinkage) due. Mainly due to hydration products of free water into a part of it39;s specific volume reduced by 1 / 4 (ie 0125cm3Pg).Therefore, the chemical shrinkage of the sizeof the reduction depends on the chemical combination of cement hydration products in the amount of water.3.1.5 Carbonation shrinkage cracking Carbonation carbonation shrinkage cracks are free ions generated by water evaporation, causing shrinkage in the slurry. Carbonation is atmospheric CO2 conditions in the water reacts with the hydration product of CaCO3, alumina, silica and water free state, this part of the volume shrinkage of concrete caused by water evaporation (known as carbonation shrinkage), and its essence is the carbonate of the cement corrosion.General alkalinity of cement hydration products and the higher the concentration of CO2 in air and moderate humidity (50%), the more prone to carbonation. Therefore, this crack propagation in alternating wet and dry environment, and dry or water saturated environment, there is not easy; and because the crack of carbide precipitation will form a gel product, stop the CO2 into, it usually only occurs on the surface.Prevention of shrinkage cracks on the above can take the following measures:(a) mixed with superplasticizer, pumping agent to minimize water consumption; construction, cutting should not be too fast, and the vibration compacting.(b) For the prevention of early shrinkage cracking, in addition to strengthening the early conservation, the final setting of concrete should be conducted before the second wiping pressure, the material can be mixed with coagulant, and the appropriate use of high early strength and good water holding capacity of ordinary Portland cement; for the prevention of shrinkage cracks, can be appropriately extended curing time, the material should use fly ash in cement and other cement or shrinkage rate of small species.(c) minimize the amount of cement, coarse aggregate content increases, and limestone as the coarse aggregate should be chosen because of its superior shrinkage cracking resistance andesite and sandstone; should strictly control the sand content of aggregate, sand ratio should not be too big, should have good aggregate grading.(d) reduce their shrinkage cracking effective way is to use a low C3A content of cement, as C3A Portland cement clinker in the greatest chemical shrinkage reduction is a C2 S 3 times, C4AF of 5 times.(e) to prevent the carbonation shrinkage cracks key is to reduce the resultant alkalinity, good for fresh concrete wet water conservation, and the use of which the concrete structure to stay as dry as other corrosive gases in the high CO2 environment to good anti-corrosionmeasures.(f) pouring concrete trowel promptly after the straw with the wet or plastic film cover, the wind should be set up wind facility construction season.3.2 Crack Crack is the concrete difference in temperature, or seasonal temperature changes and the formation of excessiveIn the concrete pouring process, the cement hydration reaction will release a lot of heat (generally 502J per gram of cement can release heat), so that the internal temperature of concrete at a certain age there temperature peak, then declined.Since the slow cooling inside the concrete surface, fast heat, will form in the temperature difference between inside and outside, for the coordination of the temperature deformation, the concrete surface will have a tensile stress (ie thermal stress), when after more than make the cracking of concrete tensile strength. Such cracks are mostly cross-cutting and deep, severely reducing the overall stiffness of the structure; usually a few months after the end of the construction. In addition, concrete curing period, if the invasion by the cold will cause cracks in the concrete surface, but the lighter, smaller and harmful. Control of temperature cracks start mainly from the lower temperature, can take the following preventive measures:(a) the materials are advised to use fly ash or cement C3A and C3 S low-low-heat cement, to minimize the amount of cement can be mixed with superplasticizer; on the concrete, can be properly mixed with stones ; in the mixing water and aggregate were mixed and ice water cooling.(b) During the construction, the construction process should be reasonable arrangements to improve the construction process, such as pouring a large volume of concrete, pipes laid in concrete or block cyclic thermal stratification placement; improve the structure of constraints, such as a long structure to be set temperature, joints or back strip, when poured on bedrock, to shop 50 ~ 100 mm sand to remove the embedded solid role.(c) in the design, calculation of thermal stress is mainly good, according to temperature stress may have taken the appropriate structural measures, such as proper temperature reinforced configuration, shared concrete temperature stress.(d) In addition, still need to strengthen the concrete curing, good surface insulation measures (such as water conservation or covering wet straw, etc.), an appropriate extension of time for form removal to the slow cooling of the concrete surface; for the concrete, control ofentry mold temperature, and for temperature tracking, control the temperature difference between inside and outside of concrete in less than 25 ℃.3.3 Subsidence cracks Subsidence cracks is all part of the building after completion caused by differential settlement occurs, mostly cross-cutting, its location and settlement in the same direction. Eight-shaped wall buildings or herringbone cracks is a typical settlement pacted backfill without treatment, formation of soft layer containing the building was in use during the ground water (rain, water, etc.) long-term immersion and other factors will cause uneven settlement of the building to crack. The foundation also works in the new construction, if not make the necessary measures (such as the set of retaining walls, diaphragm walls) to prevent soil or groundwater intrusion instability will undermine the foundations of the adjacent old building capacity, resulting in building subsidence cracking. In concrete construction, due to insufficient template rigidity, support spacing is too large, too early form removal and other factors, there will be settlement cracks.Subsidence cracks are often severely affected structures, and endanger the durability of the structure, control measures to prevent its formation are:(a) in the basic design to ensure the bearing capacity of the bearing layer of uniform strength and foundation, in the story and the different parts of the junction of old and new buildings set the settlement joint.(b) In construction, the template should have sufficient strength and rigidity, and support reliable; Also, pay attention to the construction sequence, such as after the first high-rise low-rise, after the first of the main podium.(c) Geological Survey of pre-construction work to do, as far as possible a good choice of the bearing layer, after the completion of the foundation to avoid being soaked in rainwater.3.4 Other crack In addition to these cracks, the construction process in the structure will be various forms of construction cracks; in the structure will appear during use of different types of corrosion cracks.(1) Construction of crack Construction is due to cracks in the construction of improper operation or component itself, not the stiffness of such factors.If PC project, improper tension will form a component due to strength or strength not been made insufficient cracking; template project, if the concrete form removal or bonding with the template template upgrade easily to concrete crack; hoisting project, because of lateral reinforcement component lessstiffness of poor or incorrect lifting point on factors such as cracks. The key is to prevent such cracks in strict accordance with construction specifications, such as prestressed tension must be over 75% component intensity when, brushing between the template and concrete release agent, form removal, or sliding, the first uniform loose, and then slow detachment or upgrade.(2) corrosion cracks Corrosion cracking is due to structure a long period caused by corrosive liquid environment, which includes the corrosion of concrete and its reinforcement corrosion. Such cracks are often caused by the concrete is not dense, they are usually associated with shrinkage cracks, joint action of temperature cracks, leading to crack expanding and eventually weaken the structure of durability.Control measures are mainly doing the concrete surface and reinforcing steel corrosion protection, cracks should be repaired in time. In addition, if the existing concrete aggregate base active ingredient, cement high MgO content (> 5%) or UEA expansive agent such as too much content, alkali aggregate reaction will occur, or because of the hydration reaction of MgO to produce expansion of the gel, resulting in concrete expansion cracks, formed mostly mesh or irregular cracks.Such cracks tend to occur several years after completion of the structure, because the chemical reaction is extremely slow. The key to prevention is to eliminate or reduce the concrete in the presence of such substances.4. Treatment of crack Once the cracking of concrete structures should be identified on the basis of immediately take appropriate measures. At present, the commonly used methods of surface sealing repair, pressure grouting and filling blocking method.4.1 Surface sealing Less than 012mm for the width of the micro-cracks can be polymers of cement paste, permeability of flexible sealant or waterproofing agent brushing on the crack surface, to restore its water resistance and durability. The construction method is simple, but only superficial cracks.(1) process: the surface of the bristles and wash →embedding surface defect (available epoxy cement mortar or latex) →selection of coating compound.(2) construction elements;(a) As the coating is thin and should use strong adhesive material and not aging;(b) Cracks on the activities, should be greater flexibility in material elongation;(c) Tufu uniform, not a bubble.4.2 Pressure Grouting Width and depth greater than 013mm for the larger cracks can be chemical grouting material (such as polyurethane, epoxy or cement slurry) injected by pressure grouting equipment to deep cracks in order to restore structural integrity, water resistance and durability.(1) process:cutting grooves →laid slurry seal mouth →sealing →Check →→filling →preparation of slurry sealing →grouting quality control.(2) Construction of main points:(a) grouting materials should use strong adhesive resin can be irrigated with good material, usually used epoxy resin;(b) For large crack width is greater than 2mm, cement-like material can be used for active cracks should adopt the diluted epoxy resin or polyurethane;(c) chemical grouting pressure control in the 012 ~ 014MPa, pressure control of cement grouting in the 014 ~ 018MPa, increasing the pressure does not improve the filling rate, is not conducive to filling effect;(d) after grouting, when grout without leakage when the initial setting before grouting remove mouth (boxes, tubes).4.3 Complete blocking law Width greater than 015mm for the large cracks or cracks in steel corrosion can crack the concrete digged along the "U" type or "V" groove, and then filling them with repair materials to restore the water resistance, durability or part of the restoration of structural integrity .(1) process:cutting grooves →primary treatment (decontamination of concrete, steel rust) →brushing binder (epoxy grout) →→workmanship surface repair material handling.(2) Construction of main points:(a) Filling them with materials to choose depending on the particular epoxy resin, epoxy mortar, polymer cement mortar, PVC, clay or asphalt ointment;(b) For the corrosion cracks, the first completely rust on steel, and then cover rust paint. 5．SummaryConcrete Crack is a technical problem, long plagued engineering. In recent years, with high early strength cement is widely used as commercial concrete pumping vigorously promote the construction of the concrete strength grade increase, the emergence of mass concrete, to achieve results in the crack problem, while also more prominent, and even become Concretequality focus.The present concrete shrinkage cracks are mainly caused by deformation and deformation temperature, control of these cracks in addition to the general construction in the design and construction take appropriate measures, also need researchers have developed as quickly as possible to reduce shrinkage and hydration heat of cement efficient materials, which will crack the problem reduced to minimum.混凝土裂缝成因和防治措施问题的研究探讨摘要：目前混凝土裂缝问题倍受关注,本文在对混凝土裂缝进行分类的基础上,分析了不同裂缝的形成原因,并提出了裂缝防治的措施及处理方法。
建筑施工混凝土裂缝的预防与处理(中英)
一、中文翻译建筑施工混凝土裂缝的预防与处理混凝土的裂缝问题是一个普遍存在而又难于解决的工程实际问题，本文对混凝土工程中常见的一些裂缝问题进行了探讨分析，并针对具体情况提出了一些预防、处理措施。
关键词：混凝土裂缝预防处理前言混凝土是一种由砂石骨料、水泥、水及其他外加材料混合而形成的非均质脆性材料。
由于混凝土施工和本身变形、约束等一系列问题，硬化成型的混凝土中存在着众多的微孔隙、气穴和微裂缝，正是由于这些初始缺陷的存在才使混凝土呈现出一些非均质的特性。
微裂缝通常是一种无害裂缝，对混凝土的承重、防渗及其他一些使用功能不产生危害。
但是在混凝土受到荷载、温差等作用之后，微裂缝就会不断的扩展和连通，最终形成我们肉眼可见的宏观裂缝，也就是混凝土工程中常说的裂缝。
混凝土建筑和构件通常都是带缝工作的，由于裂缝的存在和发展通常会使内部的钢筋等材料产生腐蚀，降低钢筋混凝土材料的承载能力、耐久性及抗渗能力，影响建筑物的外观、使用寿命，严重者将会威胁到人们的生命和财产安全。
很多工程的失事都是由于裂缝的不稳定发展所致。
近代科学研究和大量的混凝土工程实践证明，在混凝土工程中裂缝问题是不可避免的，在一定的范围内也是可以接受的，只是要采取有效的措施将其危害程度控制在一定的范围之内。
钢筋混凝土规范也明确规定：有些结构在所处的不同条件下，允许存在一定宽度的裂缝。
但在施工中应尽量采取有效措施控制裂缝产生，使结构尽可能不出现裂缝或尽量减少裂缝的数量和宽度，尤其要尽量避免有害裂缝的出现，从而确保工程质量。
混凝土裂缝产生的原因很多，有变形引起的裂缝：如温度变化、收缩、膨胀、不均匀沉陷等原因引起的裂缝；有外载作用引起的裂缝；有养护环境不当和化学作用引起的裂缝等等。
在实际工程中要区别对待，根据实际情况解决问题。
混凝土工程中常见裂缝及预防:1.干缩裂缝及预防干缩裂缝多出现在混凝土养护结束后的一段时间或是混凝土浇筑完毕后的一周左右。
水泥浆中水分的蒸发会产生干缩，且这种收缩是不可逆的。
建筑施工混凝土裂缝的预防与处理毕业论文中英文资料对照外文翻译文献
建筑施⼯混凝⼟裂缝的预防与处理毕业论⽂中英⽂资料对照外⽂翻译⽂献建筑施⼯混凝⼟中英⽂资料对照外⽂翻译⽂献1，⽂献原⽂：Building construction concrete crack ofprevention and processingAbstractThe crack problem of concrete is a widespread existence but again difficult in solve of engineering actual problem, this text carried on a study analysis to a little bit familiar crack problem in the concrete engineering, and aim at concrete the circumstance put forward some prevention, processing measure.Keyword:Concrete crack prevention processingForewordConcrete's ising 1 kind is anticipate by the freestone bone, cement, water and other mixture but formation of the in addition material of quality brittleness not and all material.Because the concrete construction transform with oneself, control etc. a series problem, harden model of in the concrete existence numerous tiny hole, spirit cave and tiny crack, is exactly because these beginning start blemish of existence just make the concrete present one some not and all the characteristic of quality.The tiny crack is a kind of harmless crack and accept concrete heavy, defend Shen and a little bit other use function not a creation to endanger.But after the concrete be subjected to lotus carry, difference in temperature etc. function, tiny crack would continuously of expand with connect, end formation we can see without the aid of instruments of macro view the crack be also the crack that the concrete often say in the engineering.Concrete building and Gou piece usually all take sewer to make of, because of crack of existence and development usually make inner part of reinforcing bar etc. material creation decay, lower reinforced concrete material of loading ability, durable and anti- Shen ability, influence building of external appearance, service life, severity will threat arrive people's life and property safety.A lot of all of crash of engineerings is because of the unsteady development of the crack with the result that.Modern age science research with a great deal of of the concrete engineering practice certificate, in the concrete engineering crack problem is ineluctable, also acceptable in certainly of the scope just need to adopt valid of measure will it endanger degree control at certain of scope inside.The reinforced concrete norm is also explicit provision:Some structure at place of dissimilarity under the condition allow existence certain the crack of width.But at under construction should as far as possible adopt a valid measure control crack creation, make the structure don't appear crack possibly or as far as possible decrease crack of amount and width, particularly want to as far as possible avoid harmful crack of emergence, insure engineering quality thus.Concrete crack creation of the reason be a lot of and have already transformed to cause of crack:Such as temperature variety, constringency, inflation, the asymmetry sink to sink etc. reason cause of crack;Have outside carry the crack that the function cause;Protected environment not appropriate the crack etc. caused with chemical effect.Want differentiation to treat in the actual engineering, work°out a problem according to the actual circumstance.In the concrete engineering the familiar crack and the prevention1.Stem Suo crack and preventionStem the Suo crack much appear after the concrete protect be over of a period of time or concrete sprinkle to build to complete behind of around a week.In the cement syrup humidity of evaporate would creation stem Suo, and this kind of constringency is can't negative.Stem Suo crack of the creation be main is because of concrete inside outside humidity evaporate degree dissimilarity but cause to transform dissimilarity of result:The concrete is subjected to exterior condition of influence, surface humidity loss lead quick, transform bigger, inner part degree of humidity variety smaller transform smaller, bigger surface stem the Suo transform to be subjected to concrete inner part control, creation more big pull should dint but creation crack.The relativehumidity is more low, cement syrup body stem Suo more big, stem the Suo crack be more easy creation.Stem the Suo crack is much surface parallel lines form or the net shallow thin crack, width many between 0.05-0.2 mm, the flat surface part muchsee in the big physical volume concrete and follow it more in thinner beam plank short to distribute.Stem Suo crack usually the anti- Shen of influence concrete, cause the durable of the rust eclipse influence concrete of reinforcing bar, under the function of the water pressure dint would creation the water power split crack influence concrete of loading dint etc..Concrete stem the Suo be main with water ash of the concrete ratio, the dosage of the composition, cement of cement, gather to anticipate of the dosage of the property and dosage, in addition etc. relevant.Main prevention measure:While being to choose to use the constringency quantity smaller cement, general low hot water mire and powder ash from stove cement in the adoption, lower the dosage of cement.Two is a concrete of stem the Suo be subjected to water ash ratio of influence more big, water ash ratio more big, stem Suo more big, so in the concrete match the ratio the design should as far as possible control good water ash ratio of choose to use, the Chan add in the meantime accommodation of reduce water.Three is strict control concrete mix blend with under construction of match ratio, use of concrete water quantity absolute can't big in match ratio design give settle of use water quantity.Four is the earlier period which strengthen concrete to protect, and appropriate extension protect of concrete time.Winter construction want to be appropriate extension concrete heat preservation to overlay time, and Tu2 Shua protect to protect.Five is a constitution the accommodation is in the concrete structure of the constringency sew.2.The Su constringency crack and preventionSu constringency is the concrete is before condense, surface because of lose water quicker but creation of constringency.The Su constringency crack is general at dry heat or strong wind the weather appear, crack's much presenting in the center breadth, both ends be in the centerthin and the length be different, with each other not coherent appearance.Shorter crack general long 20-30 cm, the longer crack can reach to a 2-3 m, breadth 1-5 mm.It creation of main reason is:The concrete is eventually almost having no strength or strength before the Ning very small, perhaps concrete just eventually Ning but strength very hour, be subjected to heat or compare strong wind dint of influence, the concrete surface lose water to lead quick, result in in the capillary creationbigger negative press but make a concrete physical volume sharply constringency, but at this time the strength of concrete again can't resist its constringency, therefore creation cracked.The influence concrete Su constringency open the main factor of crack to have water ash ratio, concrete of condense time, environment temperature, wind velocity, relative humidity...etc.. Main prevention measure:One is choose to use stem the Suo value smaller higher Huo sour salt of the earlier period strength or common the Huo sour brine mire.Two is strict the control water ash ratio, the Chan add to efficiently reduce water to increment the collapse of concrete fall a degree and with easy, decrease cement and water of dosage.Three is to sprinkle before building concrete, water basic level and template even to soak through.Four is in time to overlay the perhaps damp grass mat of the plastics thin film, hemp slice etc., keep concrete eventually before the Ning surface is moist, perhaps spray to protect etc. to carry on protect in the concrete surface.Five is in the heat and strong wind the weather to want to establish to hide sun and block breeze facilities, protect in time.3.Sink to sink crack and preventionThe creation which sink to sink crack is because of the structure foundation soil quality not and evenly, loose soft or return to fill soil dishonest or soak in water but result in the asymmetry sink to decline with the result that;Perhaps because of template just degree shortage, the template propped up to once be apart from big or prop up bottom loose move etc. to cause, especially at winter, the template prop up at jelly soil up, jelly the soil turn jelly empress creation asymmetry to sink to decline and cause concrete structure creation crack.This kind crack many is deep enter or pierce through sex crack, it alignment have something to do with sinking to sink a circumstance, general follow with ground perpendicular or present 30 °s-45°Cape direction development, bigger sink to sink crack, usually have certain of wrong, crack width usually with sink to decline quantity direct proportion relation.Crack width under the influence of temperature variety smaller.The foundation after transform stability sink to sink crack also basic tend in stability.Main prevention measure:One is rightness loose soft soil, return to fill soil foundation a construction at the upper part structure front should carry on necessity of Hang solid with reinforce.Two is the strength that assurance template is enough and just degree, and prop up firm, and make the foundation be subjected to dint even.Three is keep concrete from sprinkle infusingthe foundation in the process is soak by water.Four is time that template tore down to can't be too early, and want to notice to dismantle a mold order of sequence.Five is at jelly soil top take to establish template to notice to adopt certain of prevention measure.4.Temperature crack and preventionTemperature crack much the occurrence is in big surface or difference in temperature variety of the physical volume concrete compare the earth area of the concrete structure.Concrete after sprinkling to build, in the hardening the process, cement water turn a creation a great deal of of water turn hot, .(be the cement dosage is in the 350-550 kg/m 3, each sign square the rice concrete will release a calories of 17500-27500 kJ and make concrete internal thus the temperature rise to reach to 70℃or so even higher)Because the physical volume of concrete be more big, a great deal of of water turn hot accumulate at the concrete inner part but not easy send forth, cause inner part the temperature hoick, but the concrete surface spread hot more quick, so formation inside outside of bigger difference in temperature, the bigger difference in temperature result in inner part and exterior hot the degree of the bulge cold Suo dissimilarity, make concrete surface creation certain of pull shoulddint.When pull should dint exceed the anti- of concrete pull strength extreme limit, concrete surface meeting creation crack, this kind of crack much occurrence after the concrete under construction period.In the concrete of under construction be difference in temperature variety more big, perhaps is a concrete to be subjected to assault of cold wave etc., will cause concrete surface the temperature sharply descend, but creation constringency, surface constringency of the concrete be subjected to inner part concrete of control, creation very big of pull should dint but creation crack, this kind of crack usually just in more shallow scope of the concrete surface creation.The alignment of the temperature crack usually none settle regulation, big area structure the crack often maneuver interleave;The size bigger structure of the beam plank length, the crack run parallel with short side more;Thorough with pierce through sex of temperature crack general and short side direction parallelism or close parallelism, crack along long side cent the segment appear, in the center more airtight.Crack width the size be different, be subjected to temperature variety influence more obvious, winter compare breadth, summer more narrow.The concrete temperature crack that the heat inflation cause is usually in the center the thick both ends be thin, but cold Suo crack of thick thin variety not too obvious.The emergence of the this kind crack willcause the rust eclipse of reinforcing bar, the carbonization of concrete, the anti- jelly which lower concrete melt, anti- tired and anti- Shen ability etc..Main prevention measure:One is as far as possible choose to use low hot or medium hot water mire, like mineral residue cement, powder ash from stove cement...etc..Two is a decrease cement dosage, cement dosage as far as possible the control is in the 450 kg/m 3 following.Three is to lower water ash ratio, water ash of the general concrete ratio control below 0.6.Four is improvement the bone anticipate class to go together with, the Chan add powder ash from stove or efficiently reduce water etc. to come to reduce cement dosage and lower water to turn hot.Five is an improvement concrete of mix blend to process a craft, lower sprinkle of concrete to build temperature.Six is the in addition that the Chan add a have of fixed amount to reduce water and increase Su, slow Ning etc. function in the concrete, improvement the concrete mix to match a thing of mobility, protect water, lower water to turn hot, postpone hot Feng of emergence time.Seven is the heat season sprinkle to build can the adoption take to establish to hide sun plank etc. assistance measure control concrete of Wen Sheng, lower to sprinkle temperature of build the concrete.Eight is the temperature of big physical volume concrete should the dint relate to structure size, concrete structure size more big, temperature should dint more big, so want reasonable arrangement construction work preface, layering, cent the piece sprinkle to build, for the convenience of in spread hot, let up control.Nine is at great inner part constitution of the physical volume concrete cool off piping, cold water perhaps cold air cool off, let up concrete of inside outside difference in temperature.Ten is the supervision which strengthen concrete temperature, adopt to cool off in time, protection measure.11 is to reserve temperature constringency to sew.12 is to let up to control, sprinkle proper before building concrete in the Ji rock and old concrete top build a 5 mm or so sand mat a layer or usage asphalt etc. material Tu2 Shua.13 is to strengthen concrete to protect, the concrete after sprinkle build use moist grass Lian in time, hemp slice's etc. overlay, and attention sprinkle water to protect, appropriate extension protect time, assurance the concrete surface be slow-moving cool off.At the cold season, concrete surface should constitution heat preservation measure, in order to prevent cold wave assault.14 is the allocation be a little amount in the concrete of reinforcing bar perhaps add fiber material concrete of temperature crack control at certain of scope inside.5.Crack and prevention that the chemical reaction causeAlkali bone's anticipating the crack that reaction crack and reinforcing bar rust eclipse cause is the most familiar in the reinforced concrete structure of because of chemical reaction but cause of crack.The concrete blend a future reunion creation some alkalescence ion, these ion with some activity the bone anticipate creation chemical reaction and absorb surroundings environment in of water but the physical volume enlarge, make concrete crisp loose, inflation open crack.In this kind of crack general emergence concrete structure usage period, once appear very difficult remediable, so should at under construction adopt valid the measure carry on prevention.Main of prevention measure:While being to choose to anticipate with the alkali activity small freestone bone.Two is the in addition which choose to use low lye mire with low alkali or have no alkali.Three is the Chan which choose to use accommodation with anticipate to repress an alkali bone to anticipate reaction.Because the concrete sprinkle to build, flap Dao bad perhaps is a reinforcing bar protection layer thinner, the harmful material get into concrete to make reinforcing bar creation rust eclipse, the reinforcing bar physical volume of the rust eclipse inflation, cause concrete bulge crack, the crack of this kind type much is a crack lengthways, follow the position of reinforcing bar /doc/7711103392.htmlually of prevent measure from have:One is assurance reinforcing bar protection the thickness of the layer.Two is a concrete class to go together with to want good.Three is a concrete to sprinkle to note and flap Dao airtight solid.Four is a reinforcingbar surface layer Tu2 Shua antisepsis coating.Crack processingThe emergence of the crack not only would influence structure of whole with just degree, return will cause the rust eclipse of reinforcing bar, acceleration concrete of carbonization, lower durable and anti- of concrete tired, anti- Shen ability.Therefore according to the property of crack and concrete circumstance we want differentiation to treat, in time processing, with assurance building of safety usage.The repair measure of the concrete crack is main to have the following some method:Surface repair method, infuse syrup, the Qian sew method, the structure reinforce a method, concrete displacement method, electricity chemistry protection method and imitate to living from healmethod.Surface repair the method be a kind of simple, familiar of repair method, it main be applicable to stability and to structure loading the ability don't have the surface crack of influence and deep enter crack of processing.The processing measure that is usually is a surface in crack daubery cement syrup, the wreath oxygen gum mire or at concrete surface Tu2 Shua paint, asphalt etc. antisepsis material, at protection of in the meantime for keeping concrete from continue under the influence of various function to open crack, usually can adoption the surface in crack glue to stick glass fiber cloth etc. measure.1, infuse syrup, the Qian sew methodInfuse a syrup method main the concrete crack been applicable to have influence or have already defend Shen request to the structure whole of repair, it is make use of pressure equipments gum knot the material press into the crack of concrete, gum knot the material harden behind and concrete formation one be whole, thus reinforce of purpose.The in common use gum knot material has the cement the syrup, epoxy, A Ji C Xi sour ester and gather ammonia ester to equalize to learn material. The Qian sew a method is that the crack be a kind of most in common use method in, it usually is follow the crack dig slot, the Qian fill Su in the slot or rigid water material with attain closing crack of purpose.The in common use Su material has PVC gum mire, plastics ointment, the D Ji rubber etc.;In common use rigid water material is the polymer cement sand syrup.2, the structure reinforce a methodWhen the crack influence arrive concrete structure of function, will consideration adopt to reinforce a method to carry on processing to the concrete structure.The structure reinforce medium in common use main have the following a few method:The piece of enlargement concrete structure in every aspect accumulate, outside the Cape department of the Gou piece pack type steel, adoption prepare should the dint method reinforce, glue to stick steel plate to reinforce, increase to establish fulcrum to reinforce and jet the concrete compensation reinforce.3, concrete displacement methodConcrete displacement method is processing severity damage concrete of a kind of valid method, this method be first will damage of the concrete pick and get rid of, then again displacement go into new of concrete or other material.The in common use displacement material have:Commonconcrete or the cement sand syrup, polymer or change sex polymer concrete or sand syrup.4, the electricity chemistry protection methodThe electricity chemistry antisepsis is to make use of infliction electric field in lie the quality of electricity chemical effect, change concrete or reinforced concrete the environment appearance of the place, the bluntness turn reinforcing bar to attain the purpose of antisepsis.Cathode protection method, chlorine salt's withdrawing a method, alkalescence to recover a method is a chemistry protection method in three kinds of in common use but valid method.The advantage of this kind of method is a protection method under the influence of environment factor smaller, apply reinforcing bar, concrete of long-term antisepsis, since can used for crack structure already can also used for new set up structure.5, imitate to living from legal moreImitate to living from heal the method be a kind of new crack treatment, its mimicry living creature organization secrete a certain material towards suffering wound part auto, but make the wound part heal of function, join some and special composition(such as contain to glue knot of the liquid Xin fiber or capsule) in the concrete of the tradition the composition, at concrete inner part formation the intelligence type imitate to living from heal nerve network system, be the concrete appear crack secrete a parts of liquid Xin fiber can make the crack re- heal. ConclusionThe crack is widespread in the concrete structure existence of a kind of phenomenon, it of emergence not only will lower theanti- Shen of building ability, influence building of usage function, and will cause the rust eclipse of reinforcing bar, the carbonization of concrete, lower the durable of material, influence building of loading ability, so want to carry on to the concrete crack earnest research, differentiation treat, adoption reasonable of the method carry on processing, and at under construction adopt various valid of prevention measure to prevention crack of emergence and development, assurance building and Gou piece safety, stability work.From《CANADIAN JOURNAL OF CIVIL ENGINEERING》2，译⽂：建筑施⼯混凝⼟裂缝的预防与处理混凝⼟的裂缝问题是⼀个普遍存在⽽⼜难于解决的⼯程实际问题，本⽂对混凝⼟⼯程中常见的⼀些裂缝问题进⾏了探讨分析，并针对具体情况提出了⼀些预防、处理措施。
土木工程混凝土论文中英文资料外文翻译文献
土木工程混凝土论文中英文资料外文翻译文献外文资料STUDIES ON IMPACT STRENGTH OF CONCRETESUBJECTED TO SUSTAINEDELEVATED TEMPERATUREConcrete has a remarkable fire resisting properties. Damage in concrete due to fire depends on a great extent on the intensity and duration of fire. Spalling cracking during heating are common concrete behaviour observed in the investigation of the fire affected structures. Plenty of literature is available on the studies of concrete based on time temperature cures. In power, oil sectorsand nuclear reactors concrete is exposed to high temperature for considerable period of time. These effects can be reckoned as exposure to sustained elevated temperature. The sustained elevated temperature may be varying from a few hours to a number of years depending upon practical condition of exposures. The knowledge on properties under such conditions is also of prime importance apart from the structures subjected to high intensity fire. Impact studies of structure subjected to sustained elevated temperature becomes more important as it involves sensitive structures which is more prone to attacks and accidents. In this paper impact studies on concrete subjected to sustained elevated temperature has been discussed. Experiments have been conducted on 180 specimens along with 180 companion cube specimens. The temperatures of 100°C, 200°C and 300°C for a duration of exposure of 2 hours 4 hours and 6 hours has been considered in the experiments. The results are logically analyzed and concluded.1. INTRODUCTIONThe remarkable property of concrete to resist the fire reduces the damage in a concrete structure whenever there is an accidental fire. In most of the cases the concrete remains intact with minor damages only. The reason being low thermal conductivity of concrete at higher temperatures and hence limiting the depth of penetration of firedamage. But when the concrete is subjected to high temperature for long duration the deterioration of concrete takes place. Hence it is essential to understand the strength and deformation characteristics of concrete subjected to temperature for long duration. In this paper an attempt has been made to study the variation in Impact Strength of concrete when subjected to a temperature range 100oC, 200oC and 300oC sustained for a period of 2 hrs, 4 hrs and 6 hrs.The review of the literature shows that a lot of research work [1 – 3] has taken place on the effect of elevated temperature on concrete. All these studies are based on time –temperature curves. Hence an attempt has been made to study the effect of sustained elevated temperature on impact strength of concrete and the results are compared with the compressive strength. The experimental programme has been planned for unstressed residual strength test based on the available facilities. Residual strength is the strength of heated and subsequently cooled concrete specimens expressed as percentage of the strength of unheated specimens.2. EXPERIMENTAL INVESTIGATION2.1. TEST SPECIMEN AND MATERIALSA total of 180 specimens were tested in the present study along with 180 companion cubes. An electric oven capable of reaching a maximum temperature of 300oC has been used for investigation. Fine and coarse aggregates conforming to IS383 has been used to prepare the specimen with mix proportions M1 = 1:2.1:3.95 w/c = 0.58, M2 = 1:1.15:3.56 w/c = 0.53, M3 = 1:0.8:2.4 w/c = 0.4.2.2 TEST VARIABLESThe effects of the following variables were studied.2.2.1 Size sSize of Impact Strength Test Specimen was 150 mm dial and 64 mm thickness and size of companion cube 150 x 150 x 150 mm.2.2.2 Maximum TemperatureIn addition to room temperature, the effect of three different temperatures (100oC, 200oC and 300oC) on the compressive strength was investigated.2.2.3 Exposure Time at Maximum TemperatureThree different exposure times were used to investigate the influence of heat on compressive strength; they are 2 hrs, 4 hrs and 6 hrs.2.2.4 Cooling MethodSpecimens were cooled in air to room temperature.3. TEST PROCEDUREAll the specimens were cast in steel moulds as per IS516 and each layer was compacted. Specimens were then kept in their moulds for 24 hours after which they were decoupled and placed into a curing tank until 28 days. After which the specimens were removed and were allowed to dry in room temperature. These specimens were kept in the oven and the required target temperature was set. Depending on the number of specimen kept inside the oven the time taken to reach the steady state was found to vary. After the steady state was reached the specimens were subjected to predetermined steady duration at the end of which the specimens are cooled to room temperature and tested.ACI drop weight impact strength test was adopted. This is the simplest method for evaluating impact resistance of concrete. The size of the specimen is 150 mm dial and 64 mm thickness. The disc specimens were prepared using steel moulds cured and heated and cooled as. This consists of a standard manually operated 4.54 kg hammer with 457 mm drop. A 64 mm hardened steel ball and a flat base plate with positioning bracket and lugs. The specimen is placed between the four guides pieces (lugs) located 4.8 mm away from the sample. A frame (positioning bracket) is then built in order to target the steel ball at the centre of concrete disc. The disc is coated at the bottom with a thin layer of petroleum jelly or heavy grease to reduce the friction between the specimen and base plate. The bottom part of the hammer unit was placed with its base upon the steel ball and the load was applied by dropping weight repeatedly. The loading was continued until the disc failed and opened up such that it touched three of the four positioning lugs. The number of blows that caused this condition is recorded as the failure strength. The companion cubes were tested for cube compression strength (fake).4. ANALYSIS AND RESULTS4.1 RESIDUAL COMPRESSIVE STRENGTH VS. TEMPERATUREFrom Table 1, at 100°C sustained elevated temperature it is seen that the residual strength of air cooled specimens of mixes M1, M2 and M3 has increased in strength 114% for M1 mix, 109% for M2 mix and 111% for M3 mix for 6 hours duration of exposure. When the sustained elevated temperature is to 200°C for air cooled specimens there is a decrease in strength up to 910% approximately for M1 mix for a duration of 6 hours, but in case of M2 mix it is 82% and for M3 mix it is 63% maximum for 6 hours duration of exposure. When the concrete mixes M1, M2 and M3 are exposed to 300°C sustained temperature there is a reduction in strength up to 78% for M1 mix for 6 hour duration of exposure.4.2 RESIDUAL COMPRESSIVE STRENGTH VS DURATION OF EXPOSUREFrom Table 1, result shows that heating up to 100°C for 2 hours and 4 hours, the residual strength of mix M1 has decreased where as the residual strength of mix M2 and M3 has increased. The residual strength is further increased for 6 hours duration of exposure in all the three mixes M1, M2 and M3 even beyond the strength at room temperature. When the specimens of mixes M1, M2 and M3 are exposed to 200°C for 2,4 and 6 hours of duration, it is observed that the residual strength has decreased below the room temperature and has reached 92% for M1 mix, 82 and 73% for M2 and M3 mix respectively. Concrete cubes of mixes M1, M2 and M3 when subjected to 300°C temperature for 2,4 and 6 hours the residual strength for mix M1 reduces to 92% for 2 hours up to 78% for six hours duration of exposure, for M2 mix 90% for 2 hours duration of exposure up to 76% for six hour duration of exposure, for M3 mix 88% up to 68% between 2 and 6 hours of duration of exposure.5. IMPACT STRENGTH OF CONCRETE5.1 RESIDUAL IMPACT STRENGTH VS TEMPERATUREFrom the table 1, it can be observed that for the sustained elevated temperature of 100°C the residual impact strength of all the specimens reduces and vary between 20 and 50% for mix M1, 15 to 40% for mix M2 and M3. When the sustained elevated temperature is 200°C the residual impact strength of all the mixes further decreases. The reduction is around 60-70% for mix M1, 55 to 65% for M2 and M3 mix. When the sustained elevated temperature is 300°C it is observed that the residual impact strength reduces further and vary between 85 and 70% for mix M1 and 85 to 90% for mix M2 and mix M3.5.2 RESIDUAL IMPACT STRENGTH VS DURATION OF EXPOSUREFrom the Table 1 and Figures 1 to 3, it can be observed that there is a reduction in impact strength when the sustained elevated temperature is 100°C for 2 hrs, 4 hrs and 6 hrs, and its range is 15 to 50% for all the mixes M1, M2 and M3. The influence of duration of exposure is higher for mix M1 which decreases more rapidly as compared to mix M2 and mix M3 for the same duration of exposure. When the specimens are subjected to sustained elevated temperature of 200°C for 2,4 and 6 hour of duration, further reduction in residual impact strength is observed as compared to at 100°C. The reduction is in the range of 55-70% for all the mixes. The six hour duration of exposure has a greater influence on the residual impact strength of concrete. When the sustained elevated temperature is 300°C for 2,4 and 6 hours duration of exposure the residualimpact strength reduces. It can be seen that both temperature and duration of exposure have a very high influence on the residual impact strength of concrete which shows a reduction up to 90% approximately for all the mixes.6. CONCLUSIONThe compressive strength of concrete increases at 100oC when exposed to sustained elevated temperature. The compressive strength of concrete decreases when exposed to 200°C and 300°C from 10 to 30% for 6 hours of exposure. Residual impact strength reduces irrespective of temperature and duration. Residual impact strength decreases at a higher rate of 20% to 85% as compared to compressive strength between 15% and 30 % when subjected to sustained elevated temperature. The impact strength reduces at a higher rate as compared to compressive strength when subjected to sustained elevated temperature.混凝土受持续高温影响的强度的研究混凝土具有显着的耐火性能。
混凝土裂缝论文中英文资料对照外文翻译文献综述
混凝土裂缝论文中英文资料对照外文翻译文献综述Causes and control measures of concrete cracks study the problemKeywords: Causes preve ntio n of con crete cracksAbstract: At present, paid close attention to the problem of concrete cracks, this crack in the con crete on the basis of classificati on, an alysis of the causes of differe nt cracks, and proposed measures to crack preve nti on and treatme nt.1. IntroductionIs the maximum amount of con crete as a buildi ng material, widely used in in dustrial and civil con struct ion, agriculture and forestry with urba n con struct ion, water con serva ncy works in the harbor. However, many con crete structures occurs duri ng the con struct ion and use of different degreesand different forms of fracture. This not only affects the appearanee of the building, but also endanger the normal use of buildings and structures durability.Therefore, the cracks become people concerns. In rece nt years, with the ready-mixed con crete and vigorously promote the use and structure become in creas in gly large, complex, maki ng the problem eve n more prominen t.However, cracks in con crete structures is a fairly com mon phe nomenon, large nu mber of engin eeri ng practice and moder n scie nee on the con crete stre ngth of micro studies show that the structures of the crack is in evitable, which is a property of the material. Therefore, the scientific treatment of cracks in the crack problem is to classify on the basis, adopt effective measures to harmful levels of crack control to the extent permitted. This concrete structure will cause cracks in com mon, con trol measures and the repair method to an alyze some light.2. Classification of concrete cracks2.1 Divided by Crack Accord ing to the causes of con crete cracks, structural cracks andcan be divided into two major categories of non-structural cracks.⑴ Structural cracks Caused by a variety of external loads cracks, also called load cracks. It in eludes the exter nal loads caused by the direct stress cracks and the structure un der exter nal loads caused by sec on dary stress cracks.(2) Non-structural cracks Deformation caused by the change from a variety of cracks. It in cludes temperature, shri nkage and swelli ng caused by factors such as differe ntial settlement cracks. Such cracks in the structure when the deformation is restricted due to the stress caused. Research data from abroad and a large number of engineering practice, non-structural cracks in the works in the majority, about 80%, which led to shrinkage cracks.2.2Divided by the time the cracks(1) Cracks during construction Including plastic shrinkage cracks, settlement shri nkage crack ing, dryi ng shri nkage cracks, shri nkage cracks itself, the temperature cracks, the cracks were improper con struct ion operati ons, the role of early frost, and some irregular cracks caused by cracks.(2) Use of crack during In cludi ng the expa nsion of steel corrosi on cracks gen erated, salt and acid erosi on type liquid medium caused by cracks, the cracks caused by freez ing and thawing, alkali aggregate reaction, and cracks caused by cyclic loading cumulative damage caused by cracks.2.3Classification of fractured by cracks in the shape of the shape can be divided by:(1) Longitudinal cracks parallel to the bottom component, the distributionalong tendons, mainly caused by the role of steel corrosi on(2) Tra nsverse cracks perpe ndicular to the bottom comp onent mainly by theload ing, temperature effects caused(3) Shear cracks due to displaceme nt caused by vertical load or vibrati on(4) Diagonal cracks eight shaped or herringbone cracks, commorin the wall of con crete beams, mainly due to the un eve n foun dati on settleme nt, and thermaleffects caused by(5) X-shaped cracks com mon in the framework of beams, colu mns and walls onthe en ds, due to the impact effect, or mome nt loads caused by earthquake(6) All kinds of irregular cracks such as repeated freez ing and thaw ing,or fires caused by cracksIn addition, concrete mixing and transport time for long cracks due to mesh, square appears floor slab or plate surface radial cracks appear in the cross cracks and so on.2.4 The development of the state divided by cracksAccord ing to fracture the moveme nt in which the state and developme nt tren ds, can be divided in to the followi ng categories:("Stable crack This crack does not affect the persistenceof applications, includingtwo types. One is in moti on the process of self-heali ng of fractures could be com mon in a number of new water projects, this is because the crack of cement particles in the leakage of water further compounds the process, precipitate Ca (OH) 2 crystal and part of the Ca ( OH) 2 has dissolved in the water with CO2 carb on ati on reacti on to form CaCO3 crystallizatio n occurs, both the formati on of cracks in the gel material will be glued closed, and thus stop the leakage, cracks to heal. The other is in a stable movement of the cracks, such as the periodic load gen erated by the cyclical expa nsion and closure of cracks.(2)Unstable crack This will result in in stability of crack exte nsion, affect ing the susta in able use of structures, should be con sidered part of its expa nsion, to take corresp onding measures.3. Causes of cracks in concrete and control measures3.1 Shrinkage cracks Shrin kage cracks are caused by the humidity, it acco unts for non-structural cracks in concrete in the main part. We know that concrete is a cement as the main cementing material to natural sand, stone aggregate mixing water, after casting molding, harde ns and the formatio n of artificial stone」n the con struct ion, in order to en sure its workability, often adding cement hydration than water needed for 4 to 5 times more water. More of these water to free state exists, and the gradual evaporation of the hardening process, result ing in the formati on of large pores in side the con crete, voids or holes, result ing in volume shri nkage of con crete. In additi on, the harde ning process of con crete hydrati on and carb on ati on of con crete volume will lead to shri nkage. Accordi ng to the experime ntal determ in ati on of the ultimate shri nkage of con crete is about 0104% ~ 0106%.Shows that shri nkage is the in here nt physical properties of concrete, in general, the larger water-cement ratio, the higher the concrete strength, aggregate less, the higher the temperature, surface water loss is larger, the larger the value of its con tract, the more easily shri nkage cracks. Accordi ng to the formatio n of shri nkage cracks and formatio n mecha nism of the time, works in the com mon shri nkage cracks aremainly plastic shrinkage cracks, settlement shrinkage cracking and drying shrinkage cracks in three categories, in additi on to their con tract (chemical shri nkage) cracks and carb on ati on shri nkage cracks.3.1.1Plastic shrinkage cracks Plastic shrinkage cracks in concrete plastic stage, before the final set. The cause of this is concrete paste and quickly evaporating water flow to the surface, with the in crease in water loss, capillary n egative pressure gen erated by con tract ion of the con crete surface of the drastic volume shri nkage. Stren gth of con crete at a time has not yet formed, which resulted in cracking of the concrete surface.This multi-cracks in dry weather, hot an d win dy, the fracture shallow, in termediate width, both ends of the fine, of differe nt len gths, and disc onn ected.3.1.2 Settlement shrinkage cracking Settlement shrinkage cracks in concrete pouring about half an hour after the occurrenee and hardening stops. The cause of this is occurri ng after the slurry in the Pouri ng un eve n sink, sinking of coarse aggregate, ceme nt grout float, when the settlement was inhibited (such as steel or embedded parts of the block) is due to shearing and cracking of the concrete. In addition, floating in the plasma layer formed on the surface will be a result of bleedi ng and crack in g.This multi-cracks in the con crete surface, and pass along the long directi on of the rein forceme nt, or the stirrups the distributi on width of both ends of the n arrow middle, is a com mon early cracks, especially in the pump con structi on is more com mon.3.1.3 Drying shrinkage cracks Dryi ng shri nkage cracks in the con crete curi ng only appeared after completi on .Its formati on was mai nly due to the con crete to harde n, the water evaporatio n caused by shri nkage of the con crete surface, whe n the shri nkage deformati on of con crete by internal con stra int, have a greater ten sile stress to crack the con crete surface is pulled.Shri nkage cracks on the surface gen erally produces very shallow locati on, multi-comp onent along the short directi on of distributio n, were parallel, li near, or mesh, can be severe throughout the member sect ion.3.1.4 Self-shrinkage cracks Shrinkage cracks itself has nothing to do with the outside humidity, but because of the hydration reaction of cement clinker in the process, the react ion resulta nt of the average den sity of smaller volume shri nkage caused by system (called chemical shrinkage) due. Mainly due to hydration products of free water into a part of it39;s specific volume reduced by 1 / 4 (ie 0125cm3Pg).Therefore, the chemical shri nkage of the size of the reducti on depe nds on the chemical comb in ati on of ceme nt hydrati on products in theamount of water.3.1.5 Carbonation shrinkage cracking Carbon ati on carb on ati on shri nkage cracks are free ions gen erated by water evaporati on, caus ing shri nkage in the slurry. Carbon ati on is atmospheric CO2 conditions in the water reacts with the hydration product of CaCO3, alumina, silica and water free state, this part of the volume shrinkage of concrete caused by water evaporati on (known as carb on ati on shri nkage), and its esse nce is the carb on ate of the ceme nt corrosi on.Gen eral alkali nity of ceme nt hydratio n products and the higher the concen tratio n of CO2 in air and moderate humidity (50%), the more prone to carb on ati on. Therefore, this crack propagati on in alter nat ing wet and dry en vir onment, and dry or water saturated en vir onment, there is not easy; and because the crack of carbide precipitation will form a gel product, stop the CO2 in to, it usually only occurs on the surface.Preve ntio n of shri nkage cracks on the above can take the followi ng measures:(a) mixed with superplasticizer, pump ing age nt to mini mize water con sumpti on; con structi on, cutt ing should not be too fast, and the vibrati on compact ing.(b) For the preve nti on of early shri nkage crack in g, in additi on to stre ngthe ning the early con servati on, the final sett ing of con crete should be con ducted before the sec ond wip ing pressure, the material can be mixed with coagulant, and the appropriate use of high early stre ngth and good water holdi ng capacity of ordi nary Portla nd ceme nt; for the preve ntio n of shri nkage cracks, can be appropriately exte nded curi ng time, the material should use fly ash in ceme nt and other ceme nt or shri nkage rate of small species.(c) mini mize the amount of ceme nt, coarse aggregate content in creases, and limest one as the coarse aggregateshould be chosen becauseof its superior shrinkage cracking resistance an desite and san dst one; should strictly con trol the sand content of aggregate, sand ratio should not be too big, should have good aggregate grad ing.(d) reduce their shri nkage crack ing effective way is to use a low C3A content of ceme nt, as C3A Portland cement clinker in the greatest chemical shrinkage reduction is a C2 S 3 times,C4AF of 5 times.(e) to preve nt the carb on ati on shri nkage cracks key is to reduce the resulta nt alkali ni ty, good for fresh con crete wet water con servati on, and the use of which the con crete structure to stay as dry as other corrosive gases in the high CO2 environment to good anti-corrosion measures.(f) pouri ng con crete trowel promptly after the straw with the wet or plastic film cover, thewind should be set up wind facility con struct ion seas on.3.2 Crack Crack is the concrete differenee in temperature, or seasonal temperature cha nges and the formati on of excessiveIn the con crete pouri ng process, the ceme nt hydrati on reacti on will release a lot of heat (generally 502J per gram of cement can release heat), so that the internal temperature of con crete at a certa in age there temperature peak, the n decli ned.S ince the slow cooli ng in side the con crete surface, fast heat, will form in the temperature differe nee betwee n in side and outside, for the coordi nati on of the temperature deformati on, the con crete surface will have a ten sile stress (ie thermal stress), whe n after more tha n make the crack ing of con crete ten sile stre ngth. Such cracks are mostly cross-cutt ing and deep, severely reduc ing the overall stiffness of the structure; usually a few mon ths after the end of the con struct ion. In additi on, con crete curing period, if the invasion by the cold will cause cracks in the concrete surface, but the lighter, smaller and harmful. Control of temperature cracks start mainly from the lower temperature, can take the followi ng preve ntive measures:(a) the materials are advised to use fly ash or cement C3A and C3 S low-low-heat cement, to minimize the amount of cement can be mixed with superplasticizer; on the concrete, can be properly mixed with stones; in the mixing water and aggregate were mixed and ice water cooli ng.(b) During the con struct ion, the con structi on process should be reas on able arran geme nts to improve the con structi on process, such as pouri ng a large volume of con crete, pipes laid in concrete or block cyclic thermal stratification placement; improve the structure of constraints, such as a long structure to be set temperature, joints or back strip, whe n poured on bedrock, to shop 50 ~ 100 mm sand to remove the embedded solid role.(c) in the desig n, calculati on of thermal stress is mai nly good, accord ing to temperature stress may have taken the appropriate structural measures, such as proper temperature rei nforced con figurati on, shared con crete temperature stress.(d) In addition, still need to strengthen the concrete curing, good surface insulation measures (such as water con servati on or coveri ng wet straw, etc.), an appropriate exte nsion of time for form removal to the slow cooli ng of the con crete surface; for the con crete, con trol of entry mold temperature, and for temperature tracking, control the temperature differenee betwee n in side and outside of con crete in less tha n 25C .3.3 Subsidence cracks Subside nee cracks is all part of the build ing after completi on caused by differe ntial settleme nt occurs, mostly cross-cutti ng, its locati on and settleme nt inthe same directi on. Eight-shaped wall build ings or herri ngbone cracks is a typical settleme nt pacted backfill without treatme nt, formatio n of soft layer containing the buildi ng was in use during the ground water (rain, water, etc.) Iong-term immersion and other factors will cause uneven settlement of the building to crack. The foundation also works in the new construction, if not make the necessary measures (such as the set of retaining walls, diaphragm walls) to preve nt soil or groun dwater in trusi on in stability will un derm ine the foun dati ons of the adjace nt old buildi ng capacity, result ing in build ing subside nee crack ing. In con crete con structi on, due to in sufficie nt template rigidity, support spac ing is too large, too early form removal and other factors, there will be settleme nt cracks.Subsidencecracks are often severely affected structures, and endangerthe durability of the structure, con trol measures to preve nt its formatio n are:(a) in the basic design to ensure the bearing capacity of the bearing layer of uniform strength and foundation, in the story and the different parts of the junction of old and new buildi ngs set the settleme nt joint.(b) In con structi on, the template should have sufficie nt stre ngth and rigidity, and support reliable; Also, pay atte nti on to the con struct ion seque nee, such as after the first high-rise low-rise, after the first of the main podium.(c) Geological Survey of pre-c on structi on work to do, as far as possible a good choice of the bearing layer, after the completion of the foundation to avoid being soaked in rainwater.3.4 Other crack In addition to these cracks, the construction process in the structure will be various forms of con struct ion cracks; in the structure will appear duri ng use of differe nt types of corrosi on cracks.(1) Construction of crack Con structi on is due to cracks in the con struct ion of improper operati on or comp onent itself, not the stiff ness of such factors .If PC project, improper tension will form a component due to strength or strength not been made insufficient cracking; template project, if the con crete form removal or bonding with the template template upgrade easily to concrete crack; hoisting project, because of lateral reinforcement component less stiff ness of poor or in correct lift ing point on factors such as cracks. The key is to preve nt such cracks in strict accorda nee with con struct ion specificati ons, such as prestressed tension must be over 75% comp onent inten sity whe n, brush ing betwee n the template and con crete release age nt, form removal, or slid ing, the first uniform loose, and the n slow detachme nt or upgrade.(2) corrosion cracks Corrosi on crack ing is due to structure a long period caused bycorrosive liquid en vir onment, which in cludes the corrosi on of con crete and its rein forceme nt corrosion. Such cracks are often caused by the concrete is not dense, they are usually associated with shrinkage cracks, joint action of temperature cracks, leading to crack expa nding and eve ntually weake n the structure of durability.Co ntrol measures are mai nly doing the con crete surface and rein forci ng steel corrosi on protect ion, cracks should be repaired in time. In addition, if the existing concrete aggregate base active ingredient, cement high MgO content (> 5%) or UEA expa nsive age nt such as too much content, alkali aggregate reacti on will occur, or because of the hydration reaction of MgO to produce expansion of the gel, result ing in con crete expa nsion cracks, formed mostly mesh or irregular cracks.Such cracks tend to occur several years after completio n of the structure, because the chemical reacti on is extremely slow. The key to prevention is to eliminate or reduce the concrete in the presence of such substa nces.4. Treatment of crack Once the crack ing of con crete structures should be ide ntified onthe basis of immediately take appropriate measures. At present, the commonly used methods of surface sealing repair, pressure grouting and filling blocking method.4.1 S urface sealing Less than 012mm for the width of the micro-cracks can be polymers of ceme nt paste, permeability of flexible seala nt or waterproofi ng age nt brushi ng on the crack surface, to restore its water resista nce and durability. The con struct ion method is simple, but only superficial cracks.(1) process:the surface of the bristles and wash f embedding surface defect (available epoxy cement mortar or latex) f selection of coating compound.(2) construction elements;(a) As the coati ng is thin and should use strong adhesive material and not aging;(b) Cracks on the activities, should be greater flexibility in material elongation;(c) Tufu uniform, not a bubble.4.2 Pressure Grouting Width and depth greater tha n 013mm for the larger cracks can be chemical grouting material (such as polyurethane, epoxy or cement slurry) injected by pressure grouting equipment to deep cracks in order to restore structural integrity, water resista nee and durability.(1) process: cutting grooves f laid slurry seal mouth f sealing f Check f f filling f preparation of slurry sealing f grouting quality control.(2) Construction of main points:(a) grouti ng materials should use strong adhesive res in can be irrigated with good material, usually used epoxy res in;(b) For large crack width is greater than 2mm, cement-like material can be used for active cracks should adopt the diluted epoxy res in or polyuretha ne;(c) chemical grout ing pressure con trol in the 012 ~ 014MPa, pressure control of ceme nt grouting in the 014 ~ 018MPa, increasing the pressure does not improve the filling rate, is not conducive to filling effect;(d) after grouting, when grout without leakage when the initial setting before grouting remove mouth (boxes, tubes).4.3 Complete blocking law Width greater than 015mm for the large cracks or cracksin steel corrosion can crack the concrete digged along the "U" type or"V" groove, and then filling them with repair materials to restore the water resista nee, durability or part of the restoratio n of structural in tegrity .(1) process: cutting grooves f primary treatment (decontamination of concrete, steel rust) f brushing binder (epoxy grout) f f workmanship surface repair material handling.(2) Construction of main points:(a) Filli ng them with materials to choose depe nding on the particular epoxy res in, epoxy mortar, polymer ceme nt mortar, PVC, clay or asphalt oin tme nt;(b) For the corrosion cracks, the first completely rust on steel, and then cover rust paint.5. SummaryCon crete Crack is a tech ni cal problem, long plagued engin eeri ng. In rece nt years, with high early stre ngth ceme nt is widely used as commercial con crete pump ing vigorously promote the con structi on of the con crete stre ngth grade in crease, the emerge nceof mass con crete, to achieve results in the crack problem, while also more prominent, and eve n become Con crete quality focus.The present concrete shrinkage cracks are mainly caused by deformation and deformatio n temperature, con trol of these cracks in additi on to the gen eral con structi on in the desig n and con structi on take appropriate measures,also n eed researchershave developed as quickly as possible to reduce shri nkage and hydratio n heat of ceme nt efficie nt materials, which will crack the problem reduced to mi nimum.混凝土裂缝成因和防治措施问题的研究探讨摘要：目前混凝土裂缝问题倍受关注，本文在对混凝土裂缝进行分类的基础上，分析了不同裂缝的形成原因，并提出了裂缝防治的措施及处理方法。
混凝土施工裂缝原因及防治外文翻译
外文翻译资料Construction cracks in concretecauses and preventionConstruction cracks in concrete, causes and preventionConstruction cracks of concrete reason for the external and internal. The initial mainly refers to the internal defects of concrete in early concrete, its internal hardening process will exist numerous micro-pores, air-pocket and micro cracks, External refers to the load reason: temperature crack, dry shrinkage effect etc. In these, can produce various forms of concrete cracks. To grasp the construction process of raw materials, in pouring process configuration of progress and thickness, grasp timely maintenance work well, which can avoid concrete cracks. A, The cause of the tear1.The initial defects of concreteConcrete is composed of cement, sand aggregate, mixed with water and other materials and formation of heterogeneity brittle materials. In the beginning, because hardened concrete construction and deformation, a series of problems, such as constraint in the concrete shape sclerosis will exist numerous micro-pores, air-pocket and micro cracks of concrete that usually called initial defects. Micro cracks is usually a cracks in the concrete, bearing, and some other function not harm. But under load, temperature of concrete, shrinkage and function, micro cracks will be expanded and connectivity, and finally form the visible cracks of concrete, macroscopic crack, said it was the use of concrete structure, properties and durability of adverse effects.2.The load factorDue to the tensile strength of concrete structure or structures, small as a part of the external effects of stress than concrete tensile strength, will crack. Therefore, the concrete in the load and the load, can produce a crack. To load the crack, can produce by reasonable design and construction to prevent. For the load of crack, due to reasons, it is hardto handle and prevent. The more common than load factors have temperature, dry shrinkage, settling contraction deformation, plastic shrinkage deformation, etc, in these function, can make concrete inside tensile stress.3.Big volume concrete crack formation reasonsMassive concrete cracking reasons can be divided into two types: one is the structural cracks, is caused by external load, 2 it is material of crack is not caused by the changes of deformation and temperature stress and is mainly composed of concrete's shrinkage. This article mainly discussed type materials. One specific reasons are as follows: The temperature stress caused by fracture (temperature crack) temperature cracks in the main reason is caused by temperature difference. Temperature can be divided into three types: early concrete pouring, produce large amounts of the hydration heat, due to the concrete is a poor conductor of heat accumulation in concrete, the hydration heat to send out, often make internal temperatures rise, concrete and reinforced concrete surface temperature for outdoor environment temperature, it is formed, the temperature and temperature inside of condensate in early concrete tensile stress when more than concrete compressive strength, will cause cracking in concrete, In addition, in the dismantling formwork, surface temperature and reduce the temperature caused by fast, and will cause cracking. When the concrete temperature, maximum heat radiates to the minimum temperature, temperature, or use them with the highest temperature difference is the internal temperature, These three temperature will produce temperature crack. In these three temperature, is mainly caused by hydration heat and the temperature.Shrinkage crack contraction there are many causes, including drying shrinkage, plastic shrinkage, shrinkage, carbonation contraction, etc. Here mainly introduces drying shrinkage and plastic shrinkage.After drying shrinkage of concrete sclerosis, in dry environment, the water concrete to the loss caused by inside extroversion, concrete the shrinkage deformation cracks.The plastic shrinkage of cement and concrete in the activity of higher temperature, or in low water-cement condition exacerbate cause craze. When the concrete surface water obviously decreased, lactation evaporation of water cannot get the timely supplements, then concrete is still in a state of plastic, by a concrete surface tension, uneven distribution will appear the cracks of concrete cracks, and further intensify the moisture inside body, and further expansion crack Second, the measures to prevent cracksFrom the above analysis, the crack is mainly caused by temperature difference and contraction, so in order to prevent the cracks of, will maximize reduce temperature and reduce the shrinkage of concrete, specific measures as follows.1. Optimizing raw materials(1)Cement. The cement should be chosen according to the engineering properties, construction condition, climate and other technical requirements, comprehensive consideration, to meet the strength and durability of concrete design requirements. When the choice should be labeled with cement concrete design match the label. For full strength of cement, cement, cement save from the label for concrete label 1.5 to 2 times as appropriate.(2) aggregate. (a) coarse aggregate. The coarse aggregate concrete rubble is close-grained, must have the enough strength, hard to expand the coarse aggregate size. To ensure the concrete pouring dao close-grained, coarse aggregate maximum diameter less than the minimum size of the structural sections 1/4, also not greater than the minimum distance between steel net for thickness 3/4, in 10 centimeters and concrete, allowing adoptsmaximum diameter 1 1/2 of the aggregate number, but it shall not exceed 25%. (b) fine aggregate. Sand particle gradation of technical properties of concrete influence, requests the porosity and total surface area small, small need total surface on the surface of the gravel package will reduce quantity of cement slurry, can reduce the dosage of cement hydration heat, reduce to prevent cracks. On the other hand is to control the hydraulic sand, the content of 5% in concrete, "the contraction deformation, the hydraulic and larger crack, fine aggregate to use clean in the sand.(3) admixtures. (a) water-reducing agent. Jianshuiji belongs to the surface active substances, is a kind of cement dispersant. Its main function of improving concrete workability, reduce the consumption of concrete mixture, reduce water-cement ratio increases, and improve the liquidity of concrete strength of concrete or keep in concrete cement strength must decrease, while the water-cement ratio, the dosage of cement to prevent cracking is reduced. (b) retarder. Retarder is delaying the role of concrete exothermic peak time, 2 it is to improve workability, and reduce the loss of collapsbillity. (c) air-entraining agent. In the application of concrete air-entraining agent for improving the concrete workability, can pump, improving the concrete durability is very favorable. In a certain extent increase anti-cracking performance of concrete.(4) mass concrete chooses raw materials should pay attention to the following:①The coarse aggregate gradation, appropriate USES continuous fine aggregate ZhongSha should be adopted.②Admixtures appropriate USES retarder, water-reducer, Admixtures appropriate USES fly ash, slag powder etc.③In mass concrete strength of concrete and the slump and the requirements of the premise, should improve mixing and aggregate content,in order to reduce the dosage of cement concrete alone.④ Should try to choose cement hydration heat low, setting time is long, the cement, low thermal Portland cement slag silicate cement, cement, slag dam Portland cement, coal ash Portland cement, volcanic gray Portland cement, etc.However, the slag cement hydration heat low water cement ratio of chromatography in other large, casting lots of water surface layer. This phenomenon is not only affect lactation water, also influence the construction speed and quality of construction. Because the water gathered in separation between the two casting concrete surface layer, change, and water-cement ratio in the water and took out some of the mortar, thus forming a layer of interlining content, destroyed the cohesive force of concrete and holistic. The size of the water concrete lactation with water water, water, lactation; And with the temperature, water separation of time with temperature completely and shortening, In addition, also with the composition and fineness of cement. Therefore, in selecting slag cement should be chosen when the varieties, and lactation shall be adding water-reducing agent in concrete, to reduce the consumption. During construction, should be in water or mixing some tomography uniform rolling cement casting in water, with 3-degrees vibration compaction, continue again after a concrete casting.2.the reasonable construction method(1) The concrete mixing and transportation. (a) white, accurate grasp of concrete proportion, especially the strict control of water consumption, the determination of sand. Records of every block water cement, sand and gravel, specific quantity, the application must be accurate to scale, by mixing. Good control of concrete slump and general shoulds not be too big, in 120 ± 20 mm. To minimize the mouth 3 concrete temperature. (b) concrete mixing in a storehouse after good transportprocess, to prevent to produce separation, lactation water, mortar loss should shorten transportation time, concrete loading not too full. (2)Concrete pouring and open mode. Pouring process may be close-grained, vibration to vibration time should be uniform in surface functional plasma advisable, uniform spacing, vibrating force scope affected overlap 1/2 advisable, after casting, compaction, surface must, in order to prevent the surface crack. Try to avoid in the solar radiation, high time due to the needs of the project if pouring in summer construction, avoid noon pouring temperature period, try to arrange at night. Time should be removed, according to air temperature and strength. In the actual temperature curing of the concrete conditions of strength, strength design of concrete center and 75%, the lowest temperature control surface in 25 degrees Celsius, expected the concrete surface temperature drop more than 9 degrees Celsius above does not allow removed.(3) Do surface insulation protection of mass concrete temperature crack, is mainly caused by excessive temperature. Concrete pouring, due to internal heat faster, more surface temperature will form the internal and external surface by internal restraint, contraction, but the tensile stress, not more than usually have small tensile strength and the concrete cracks. But if the air raid, or by excessive ventilation cooling, make the surface temperature will easily lead to excessive temperature crack in the concrete, and so on, especially after dismantling formwork, low season in the immediate surface protection. To prevent excessive temperature crack, cause surface. In addition, the average day temperature in 2 ~ 3d consecutive decline not less than 6 ~ 8 degrees Celsius, 28d age concrete surface must surface within the protection.(4) Of the mass concrete casting:Construction scheme, besides should satisfy each place of concrete in early before a new concrete are covered and rammed finished outside,still should consider structure size, steel pipe, buries the bolts and leave, concrete and hydration heat supply, the influence of factors such as the commonly used method has the following kinds:Comprehensive stratified:In the first layer after pouring all comprehensive casting, casting back second, should make the first layer of concrete yet, so early, continuous casting until completion by far. Using this scheme, applicable to the general structure of planar size shoulds not be too big, when construction from the short side began to push along the long side, is more appropriate. When necessary, can be divided into two sections from middle to both ends to or from the middle and construction.Section 2 layer:Concrete casting, starting from scratch, casting a certain distance to the second floor, so after pouring in other layers on casting. Due to the total number of layers, therefore, after the first layer top pouring concrete yet at the end of the beginning of the second period, and can turn from layered casting. This scheme is applicable to units within the time required, the supply of concrete less like the first option on that. This scheme is applicable to structure is too big and thickness of large area or length.Incline stratified:Requirements of slope not greater than cant 1/3, applicable to greatly exceed the length of the structure of the thickness of the three times. From the bottom layer of concrete casting, gradually move.3.maintenance measuresMaintenance of mass concrete construction is a vital work. Maintain proper maintenance is mainly to control temperature and humidity, temperature, promote concrete outside the normal development of the strength of concrete and prevent the cracks of concrete and development.According to the specific circumstances of should as far as possible much maintenance period of time, after dismantling formwork should immediately, covering protection to prevent recent climate, sudden cold temperature, prevent and control in early concrete cracks and medium. The massive concrete curing, not only to satisfy the need that still should increase by artificial temperature control, due to temperature caused by deformation of the concrete cracking. After the completion of the concrete curing time to keep the concrete surface spraying maintenance, such as reducing often humid heat outside pour cans, and prevent dry crack and promote the stable growth of concrete strength. In general 18h 12 ~ after pouring in immediately start maintenance, maintenance time not less than 28d or design age.4 CooledIf in the high-temperature seasonal construction, should be in early general refrigeration adopted to reduce the water temperature, but the peak of concrete, water cannot too long, for a long time can cause excessive temperature range of temperature stress caused by large. In order to cut inside and outside, still should temperature in summer jiamoqiuchu undertake metaphase is cooled by water, river, general middle water lasted about two months. Later, water is made concrete cylindrical blocks the necessary measures to juncture grouting, generally USES water and cooling water through the combination scheme.Third, the conclusionConcrete crack, especially large volume concrete crack is currently scholars and engineering is an important problem of attention, through the above analysis, the material of mass concrete crack is mainly composed of temperature stress and concrete's shrinkage, the author thinks carefully select material, and in the use of reasonable construction method, can effectively prevent the cracks.混凝土施工裂缝原因及防治混凝土施工裂缝原因不外乎外因和内因。
建筑施工混凝土裂缝的预防与处理 毕业论文外文翻译
建筑施工混凝土裂缝的预防与处理毕业论文外文翻译Prevention and Treatment of Concrete Cracks in ConstructionAbstract：Concrete has been widely used in construction because of its good durability and high structural strength. However, concrete is prone to cracks during construction, which can seriously affect the performance and service life of buildings or structures. Therefore, it is necessary to take preventive measures to reduce the occurrence of cracks in concrete. This paper summarizes the causes of concrete cracks and the measures to prevent and treat concrete cracks in construction, aiming at providing a reference for concrete construction engineering.Keywords：concrete; cracks; prevention; treatment1 IntroductionConcrete has been widely used in the construction industry due to its good durability, high structural strength and other advantages. However, concrete is also prone to cracks during construction, which can seriously affect the performance and service life of buildings or structures. Therefore, it is necessary to take preventive measures to reduce the occurrence of cracks in concrete.2 Causes of Concrete Cracks2.1 Internal Causes2.1.1 Material QualityThe quality of the concrete material directly affects the strength and durability of the concrete structure. If the raw materials are not properly prepared or mixed, the quality of the concrete will be affected, leading to cracks in the structure.2.1.2 Technical FactorsDuring the pouring and curing processes of concrete, technical factors such as the amount of water added, the mixing time, the compactness of the concrete, the curing conditions and the temperature control, etc., will affect the strength and durability of the concrete structure.2.2 External Causes2.2.1 Environmental FactorsDuring the construction of concrete structures, environmental factors such as temperature, humidity, wind, rain and snow, etc. can have an impact on the strength and durability of the concrete structure. For example, low temperatures can cause the concrete to freeze and form cracks, while high temperatures can cause the concrete to expand and crack.2.2.2 Load FactorsLoad factors refer to the external forces that act on the concrete structure, such as weight load, wind load, earthquake load, etc. If the load is too large or unevenly distributed, it can cause cracks or deformation in the concrete structure.3 Prevention of Concrete Cracks3.1 Ensure Good Construction QualityThe construction quality of concrete structures directly affects the occurrence of cracks. Therefore, in the construction process, it is necessary to strictly follow the design and construction specifications, and pay attention to the quality control of all aspects of the construction.3.2 Reasonably Design the StructureReasonable structure design can effectively prevent cracks in concrete. The design of the construction joints, expansion joints and contraction joints should be reasonably determined according to the characteristics of the structure and environmental factors to prevent the occurrence of cracks caused by temperature changes or load factors.3.3 Strengthen the Construction JointsStrengthening the construction joints can effectively prevent the occurrence of cracks in the joints between the old and new concrete structures, and between the precast concrete components and the cast-in-place concrete structures. Reinforcement measures can be taken to ensure the continuity and uniformity of the joints.3.4 Control the Temperature and HumidityControl of the temperature and humidity during the pouring and curing of the concrete is also an important measure to prevent the occurrence of cracks. The temperature and humidity must be controlled within a reasonable range to ensure the normal hydration and curing of the concrete.4 Treatment of Concrete Cracks4.1 Grouting and SealingGrouting and sealing are common methods for treating cracks in concrete structures. The method is to inject a certain amount of grouting material into the cracks to fill the gaps, and then use sealing materials to seal the surface of the cracks to prevent the intrusion of water and other substances.4.2 Patching and ReinforcementFor concrete cracks caused by insufficient structural strength or uneven load distribution, patching and reinforcement methods can be used. The method is to apply a new layer of concrete or repair mortar to the surface of the cracks to increase the strength and load-bearing capacity of the structure.4.3 ReplacementFor severe cracks or damaged concrete structures, replacement is often the only way to solve the problem. The method is to completely remove the damaged parts and replace them with new concrete or precast components.5 ConclusionIn summary, concrete cracks are a common problem in the construction industry, but they can be prevented and treated through effective measures. In the construction process, attention should be paid to the quality of the concrete material, the technical factors, and the environmental and load conditions. In addition, reasonable structure design and strengthening of the construction joints, as well as control of the temperature and humidity, should be considered to prevent the occurrence of cracks. For existing cracks, grouting and sealing, patching and reinforcement, or replacement methods can be used to effectively repair the damaged structures.。
建筑施工管理中英文对照外文翻译文献
中英文对照外文翻译文献(文档含英文原文和中文翻译)Construction stage safety civilization management1 Research content and purposeAt present China's production safety situation is still grim, especially the building area of the multiple casualties situation has not fundamentally reversed, construction safety is extremely stern; production safety foundation is weak, guarantee system and mechanism is not perfect; safety production supervision and management mechanism, team construction and supervision work also needs to be strengthened.With China's implementation of the "going out" strategy, the overseas engineering construction requirements of construction enterprises toward the safety and high quality fast and efficient direction, but the due to the overseas projects in surveying, design, competitive bidding system and construction exists some defects or mistakes, especially the construction environment and conditions for overseas and domestic different is formed many unsafe factors. Some governments of developed countries on safe and civilized construction management and supervision ineffective, at the same time, the security incident victimscompensation is relatively low, so as to project management are real will "safety first" self psychological suggestion and safe and civilized management psychological orientation proposed higher requirements. And in the preparation of the overseas project safety assurance program, sometimes due to lack of understanding in the engineering field, easy to cause the of dangerous source judgement is not accurate or not in place, and psychologically cannot accurately to ensure the safety of the positioning of the feasibility of the program.By exploring the harmful factors in the construction process and construction process was studied in unsafe, uncivilized between factors and employee of contradiction and the law of the unity of opposites, making better use of these rules to formulate a scientific, reasonable, effective all safe and civilized production tube system, to improve and perfect the measures of safety and technological civilization, to prevent and eliminate various harmful factors in the process of construction to the conversion of the casualty of a series of management work, to protect workers' safety and health, ensure safety in production. Due to the construction of the unsafe factor is relatively more, a little careless, it may occur accident. In recent years, occurred throughout the country in the construction work accidents and serious casualty statistics tells us that construction of the security situation is still very grim. However, construction safety problems with everything else, has its own objective law. It objectively resides in the entire construction activity. Since so, naturally, be it analysis to understand, master rules of it, take the organizational and technical measures to pre control, in order to achieve the purpose of construction safety. However, there are still many problems in the management of the security civilization.Therefore, we focus on the construction stage of the construction safety civilization management, the construction of the various aspects of the construction plan, the status quo of the safety and civilization management. Through the safety awareness of the management, the system of planning, to the project safety detailed analysis of the content. There are some unpredictable problems during the process of preparation, which is the main problem in the management of safety civilization.. Lay a good foundation for further implementation.. According to the occurrence of the settlement of the accident, there is no accident occurred, record the safety civilization management improvement measures, improve the safety and civilization management. As generally work arrangements properly was period of management is relatively lax, cross process serious and complicated, and safety problems inthis period is often risks and security alert frigidity, may not out of the big problem, but small problems and small risks constantly. So strengthen safety education and training, the unknown engineering safety civilization management summary, learning.Through the research on the safety civilization management of the construction stage, the danger identification, the risk assessment and the risk control of the modern safety civilization management are discussed in three aspects.. The aim is to better and more secure the work done. Do early work after the reduction of risk, and further strengthen the construction project risk management, and thus promote the faster development of China's construction projects.2 Status quo of safety civilization managementIn recent years, with the continuous improvement of the market economy and the common improvement of people's life, construction industry has become one of the fastest developing industries. The competition of the market is increasingly fierce, so that the benefit of the enterprise to compete in the target, so to the management to benefit has become the consensus of entrepreneurs. And safety is the premise of the benefit, because the safety results determine the size of the benefit. End over the years the party and the government attaches great importance to production safety work, determine the safety production policy of "safety first, prevention first", promulgated a series of production safety laws and regulations and standards, the purpose is to protect the safety and health of laborers, control and reduce all kinds of accidents, improve the level of safety management, promote the establishment of harmonious society.The construction industry is the risk of production activities, unsafe factors, is the accident prone industry. In recent years, the death rate of China's construction industry is the highest in all industries, after the mining industry, the loss is huge, distressing. Although the mandatory implementation of the construction enterprise safety production license system, strengthen the construction market access control, and to further strengthen the construction enterprise construction site safety inspections, but accidents still occur from time to time. I believe that the number of casualties mainly determined by the characteristics of the construction industry. The safety civilization management is a science, is a professional, policy, mass, and a very strong work. The safety civilization management of the enterprise is mainly embodied in the following aspects:(1) Safety awareness. Due to the leading enterprises for a long time the importance ofconstruction safety understanding does not reach the designated position, grasping safety formalism serious, disregard for workers in the production of the legitimate interests of labor and social security, is not equipped with the necessary labor protection supplies, arbitrary extension of working time, workers in the long run, the working state of the overload, high strength, will lead to accidents. In addition, the leadership of the security work seriously enough, the staff of the corresponding security awareness, it is easy to cause illegal command, illegal operations, violation of labor discipline and safety accidents caused by.(2) The weak base of security civilization management. The weak security and civilization management is mainly due to the weak safety consciousness of some people, the relationship between the safety and the speed, safety and the relationship between safety and benefit, security and stability.. The weak safety management is mainly reflected in the weak: first, the research work of building safety technology is weak, and the key technology of building safety production is relatively lagging behind. The wide application of safety scientific and technological achievements is lack of market-oriented policy guidance and economic incentive measures. Study on the construction of new technology, new products, new technology application and safety protection measures of synchronization; second, compared with the developed countries, our country security protection technology, protective equipment and machinery and equipment is still relatively backward. Standardization, stereotypes and industrialization degree is very low; three is the construction enterprise safety civilization management and construction team quality is generally low. The safety of the low quality of the cultural quality, safety and civilization management knowledge, safety and technical specifications, safety procedures, safety precautions and so on do not understand. Can't manage the construction team.(3) The construction safety laws and regulations system is not perfect. There are some limitations to implement its security responsibilities; terms of punishment for violations of the law is not specific enough, operability is not strong; laws and regulations are not perfect, there is a problem of duplication and overlapping management; safety rules and regulations of the responsibility is not clear, management objectives is not clear, resulting in production safety responsibility of implementation is not in place etc..(4) The mechanism of the construction safety supervision and production is not perfect. At present, the mechanism of the effective construction safety supervision and management inChina has not been formed, and there is a big gap compared with the international advanced security management mode.. The safety supervision mode and management means can't adapt to the growing scale of construction, and it is difficult to carry out the construction safety supervision work further.. Mainly in the following three aspects:Construction unit safety civilization management problemThe exploration, design, construction and supervision of the construction engineering to the entity or individual contractor who is not qualified or qualified or even illegal. Due to the layers of subcontracting, resulting in the construction management is not strict, security training is not in place and security investment or basic no. And it will also make lower profits, and contractors in order to pursue the maximal profit will reduce his all unnecessary amount of spending, leading to safety hazards and accidents continue to occur.Investigation, design, engineering supervision and other units of the major security issuesSurvey, design units not in accordance with the requirements were survey or design, or change the survey and design documents, laws, regulations and mandatory standards, to survey the design defects, can not guarantee the building and construction personnel safety engineering supervision units not to the construction unit safety technical measures or special construction safety program for careful review, in the engineering construction nor of construction units to implement security measures of supervision seriously, find the hidden accident, nor does it take decisive measures to be rectification and elimination; detection unit to produce a false report.Safety problem of construction unitWith the increasing investment in infrastructure, the construction enterprise access policy adjustment, making the number of construction enterprises continues to increase, the construction team continues to expand. Especially in recent years, the rapid development of individual construction industry, the construction enterprise has changed fundamentally. But because the construction unit is the main body and the core position in the construction safety activity, the construction safety problem is mainly in the construction unit body.2.1 Government laws and regulations(1) The lack of building safety and civilization management system for the market economyConstruction of China's investment system changes the original building a safe and civilized production management has not adapt to the current construction methods, so has been dominated by the government of safe and civilized management appeared many loopholes in management, coupled with the construction safety laws and regulations is not perfect, the low efficiency of government supervision, social supervision system is not perfect, resulting in a safe and civilized management is not in place, suited to the laws of market economy, legal and economic means parallel building a safe and civilized management system has not been formed. Therefore, the initiative construction safety civilization management initiative construction safety civilization management work first, early planning, early arrangement, do the whole process supervision and inspection. Before the construction we put the project in the province Shuangyou site as the target management, improving the safety management measures and system in the project, accomplish beforehand to prevent. Employees entering the construction site, the first production safety education and follow the operating rules of education; followed by a safety technical disclosure and each segment and sub engineering safety technical disclosure, so that all staff familiar with the rules and regulations, consciously abide by the safety regulations and operating rules, improve the sense of self-protection. Strengthen the intensity and extent of the supervision of the safety and civilization management objectives for effective control.(2) The law and regulations are more and more incomplete and the execution is not enoughOur country law "environment and health" is too weak. The emphasis on "environment and health" in the activity of architecture has become a common topic of international concern. The target system of engineering construction has been shifted from the traditional "cost - cost - quality - time - to - Project" system to "cost - quality - time - environment and health" system.. The international standard organization has also developed the environmental management system.(3) The functional changes of the management department are lagging behind and the management of the vacuum isWith the deepening of the reform of our political system, the reform of the national institution, the enterprise reform, the enterprise has gradually separated from the industry administrative management, and has become the independent action subject in the market.With this adaptation, Ministry of construction and local construction administrative departments to become the national construction safety special supervision of the performer, state production safety supervision and administration and the local production safety supervision and management institutions become discharger of the state production safety supervision functions.The unsafe state of the unsafe behavior and the unsafe state of the material are the direct cause of the accident, which are directly related to the management. So the management is the indirect cause of the accident.. The unsafe behavior of human can be reduced or even eliminated through safety education, safety production responsibility system and security mechanism. The unsafe state of the material can be controlled by improving the scientific and technological content of the safety, establishing the perfect equipment maintenance system, promoting the construction and safety of the civilization. To strengthen the safety inspection on the job site, we can find and stop the unsafe behavior and the unsafe state of the thing, so as to avoid the accident. One of the most common defect management system is not perfect, the responsibility is not clear, abiding by the law, the illegal command, safety education is not enough, punishment is not strict, safety technical measures are not comprehensive, security check enough.(4) The construction safety production management and professional construction safety production management separateAt present, China's construction safety civilization management is actually decentralized management, did not really do the industry management. This has formed the construction safety civilization management standard, the management pattern is different, the casualty statistics data distortion, the management work responsibility is not clear.Pay attention to safety behavior norms according to the laws of science organization construction, comply with construction safety rules and standards, as a code of conduct to organize the construction of construction site to be constrained, regulate their behavior from two aspects: one is to require managers to strictly implement the construction administrative departments of the state and local issued by the construction safety and civilized management regulations and standards the implementation of the management system of the enterprise, before the construction of the relevant technical requirements for the construction safety to the crew and workers in detail, and signed by both parties confirmed that security staff dailyinspections of implementation; two is to require the operation layer; safety protection for the outstanding construction site could cause accident.2.2 The characteristics of the construction safety civilization managementThe characteristics of construction are mainly determined by the characteristics of architectural products. Compared with other industrial products, building products is huge in size, complexity and diversity, overall hard, not easy to mobile, so that construction in addition to the basic characteristics of industrial production, but also has the following main features:(1) The fluidity of productionOne is the body construction with the buildings or structures located position change and the transfer of production sites; the second is in the process of the construction of a project construction personnel and all kinds of machinery, electrical equipment with the construction site and along the construction of the object up, down, left and right flow, continue to turn shift operation places.(2) The product form is diverseDue to the natural conditions and uses of the building, the structure, modeling and material of the building are also different, and the construction method will be changed, it is difficult to realize the standardization.(3) Construction technology complexConstruction often need according to the structure of the building for many types of work with the operation, multi unit (earthwork, civil engineering, hoisting, installation, transportation, etc.) cross tie construction, the supplies and equipment are different, thus the construction organization and construction technology management has a higher request. Most of the construction industry is still manual operation, easy to make people fatigue, attention dispersion, so improper operation or mistakes more prone to occur, Rong Yi lead to accidents security. This is manual labor and heavy manual labor and more.(4) Open and aloft operationsThe building product is huge, the production cycle is long, the construction is carried on frequently in the open air and the high place, is often influenced by the natural climate condition. According to the national standard "high job classification" provides that there are more than 90% of the construction of higher operations. The open operation of buildingsaccounts for about 70% of the total workload, and the impacts and hazards of natural conditions such as spring, summer, autumn and winter, and sunshine, wind, rain, snow and snow etc.(5) Low mechanizationAt present, the construction mechanization degree of our country is still very low, still depend on a lot of manual operation.. Construction machinery and machinery in the factory compared to the mechanical equipment is very different, its safety is much higher than the factory equipment, the probability of injury is naturally much higher. There are several aspects of the following features:A. Use of different environmental conditions;B. Operating object is different;C. Operating location and operator;Take the crane as an example to discuss the mechanization of safety civilization management.In our country, with the increase of the number of the heavy machinery, the proportion of the injury accidents in the total industrial accidents is also increasing year by year. The common accidents of hoisting machinery are: the hanging falls, the impact of extrusion, the accident, the electric shock accident, the body dump accident.. The total number of crane crashes accounted for about 33%, the impact of extrusion accounted for about 30%, electric shock accounted for about 10%, the accident accounted for about 8%, the body dumping accounts for about 5%. The total number of the total number of injuries from the accident of the highest percentage of falling accident analysis:A. Off the rope accidents: due to the load from a bundle of the hoisting rope shedding collapsibility casualties damage.B.Weight loss accident from heavy lifting rope or special sling from hook caused by prolapse.C. Broken rope accident: hoisting rope and hoisting rope broken down due to the weight loss accident.D. Hook broken accident: weight loss accident fracture caused by hook.E. Hoisting wire rope problem.2.3 The work content of the construction safety civilization managementConstruction enterprises to do a good job security construction should pay attention to do the following several work:(1)Thinking;(2) Establishment of a safety production management system;(3) Establishing the safety and professional bodies and with full-time safety technicians;(4) Ensure that the workers are safe and secure;(5) Take the targeted safety measures;Safety technical measures should be aimed at the engineering features, in depth investigation and study. Also do a good job of work safety technical disclosure.3 Security checkThe security check is found in time, eliminate hidden dangers of accidents, an effective way to nip in the bud. The construction product volume is huge, the height operation is high, and then combined with the construction period, the technology complex and other factors, to the construction production brings a lot of unsafe factors. Through the combination of leadership and mass security checks, can effectively find the problem, take measures to eliminate the accident before the occurrence of the accident. Safety inspection can also summarize the good experience of the exchange of safety production, establish a typical, to promote the level of safety and civilization management. Mobilize the masses for security checks, both to encourage the masses to participate in the enthusiasm of safety and civilization management, and can educate the masses to enhance awareness of the safety awareness of production, and consciously improve the safety of production. In addition, the safety inspection can often give the neglect of the safety of the idea of knocking the alarm, and promptly correct illegal command, illegal operations behavior.4 SummarySafety civilization management is a science, is a professional, policy, mass, and a very strong work. With the continuous development of the economy, the continuous improvement of people's living standards, employees in the construction industry and the whole society are on the construction process of safe and civilized management level proposed requirements more and more high, the traditional management mode has not adapted to the requirements of the times. It is now in need of scientific and modern enterprise security and civilization management mode, and continuously improve the level of safety civilization management, thereal safety civilization management work well. The scientific use of PDCA circulation method, the pair of leaders of all levels of safety education and construction plan possible accident, the implementation of safe and civilized management plan, make safe and civilized management is better in the construction of perfect embodiment. To inspect the construction process of the construction management plan, and find the problem that hidden and haven't met to solve, analyze and record, and put the security plan into the program. To reach a circular process. Therefore, as the construction enterprise, we should study the status quo of the construction industry safety civilization, establish the new idea of safety civilization management, and establish new accord with the.Construction safety management civilization is the first human management, to strengthen the safety education and training, continuously improve the quality of security business, enhance security awareness, and to take effective measures to regulate people's behavior, to implement standardized operation, in construction process due to the complexity of the construction site personnel, dynamic and frequent, in project management, to take admission to tertiary education and the change of production and construction, timely safety education; combination of production safety skills training, in order to enhance staff safety consciousness of responsibility and security capabilities.Through the safety civilization management education and training, strengthen the construction safety and the implementation of the guarantee. Safety education is the most effective method in the safety civilization management. Both time and greatly reduce the cost. On the construction enterprise personnel, from the leadership to the construction workers are admitted to the education and training, the whole aspect to strengthen safety awareness. A clear division of labor and management, the construction project without mistake, reduce the mistake. Building a safe and civilized management is a very complex system engineering, we must use of scientific management methods, management methods, the establishment of new safe and civilized management mode to improve worker safety execution. Only in this way, we can really make a safe and civilized management level to a new level.施工阶段的安全文明管理1.研究内容与目的目前我国的安全生产形势依然严峻，特别是建筑领域伤亡事故多发的状况尚未根本扭转，建筑施工安全极其严竣；安全生产基础比较薄弱，保障体系和机制不健全；安全生产监督管理机构、队伍建设以及监管工作还待加强。
混凝土裂缝的产生与预防 毕业论文外文翻译
混凝土裂缝的产生与预防毕业论文外文翻译The production and prevention of concrete cracksAbstract：This paper discusses the reasons for the production of concrete cracks and the preventive measures for cracking in the construction process. In the production process of concrete, it is influenced by many factors, such as temperature, humidity, mix materials, construction technology, etc., which may lead to the formation of cracks in the concrete structure. This article analyzes the causes of concrete cracking from various aspects such as raw materials, mixing, placing, and curing, and puts forward corresponding preventive measures. The purpose of this paper is to provide a reference for the prevention of concrete cracks in the construction process and to improve the quality of the engineering.Keywords：concrete, crack, production, prevention1. IntroductionConcrete is one of the important building materials in modern engineering, and it is widely used in various types of buildings, road construction, and infrastructure projects. The quality of concrete is directly related to the safety and durability of the structure, and the requirements for the quality of the concrete become higher and higher as the engineering technology advances. In order to improve the quality of the concrete, it is necessary to control the factors that affect the production and use of the concrete, especially the phenomenon of concrete cracking.The production and use of concrete are influenced by various factors, such as the raw materials, mixing, placing, and curing, which may cause concrete cracking. Therefore, it is necessary to analyze the factors that cause concrete cracking and adopt corresponding preventive measures in the construction process to prevent the occurrence of cracks in the concrete structure.2. The reasons for the production of concrete cracks2.1 The impact of raw materialsThe quality of raw materials, such as cement, aggregate, admixture and water, has a direct impact on the properties of concrete, and the quality of concrete isdirectly related to the occurrence of cracks. In the production process, if the quality of the raw materials is not good, it will affect the strength, elasticity, and crack resistance of the concrete.For example, if the water-cement ratio of the concrete is too high or the particle size of the aggregate is uneven, it will cause the internal pores to increase and the distribution to be uneven, which will reduce the compactness of the concrete, thus causing cracks in the hardened concrete. If the quality of the admixture is not good, it will affect the workability and cohesiveness of the concrete, and affect the fluidity of the concrete, which may cause cracks in the concrete.2.2 The impact of mixingMixing is a key process in the production of concrete, and the quality of mixing directly affects the properties of concrete. If the mixing is improper, it will cause the concrete to have uneven density, segregation, bleeding, and other phenomena, and the hardened concrete will be prone to cracking.For example, if the mixing time is too long, it will cause the concrete to segregate, the coarse aggregate to sink, and the mortar to float, which will cause the internal stress of the concrete to increase and crack under the action of external force. If the mixing speed is too fast, it will cause the air entrainment rate of the concrete to increase, which will reduce the density of the concrete and reduce the strength of the concrete.2.3 The impact of placingPlacing is the process of conveying concrete to the site and properly placing it in the formwork. If the placing operation is not standardized or the environmental conditions are not suitable, it will cause the concrete to be unevenly stressed and result in cracks in the structure.For example, if the pouring time is too long, the concrete will lose workability and result in poor compaction, which will lead to the occurrence of segregation and bleeding. If the temperature of the environment is too high or too low, it will affect the hydration of the cement and cause cracks in the hardened concrete.2.4 The impact of curingCuring is the process of keeping the concrete wet and at a suitable temperature after placing, in order to promote the continuous hydration of cement and the growth of the strength of the concrete. If the curing is not timely and sufficient or the curing conditions are not properly controlled, it will cause the concrete to lose moisture and strength, and lead to the occurrence of cracks in the concrete.For example, if the concrete is cured in a dry environment or exposed to sunlight, it will cause the surface of the concrete to dry out quickly and shrink, thus leading to the occurrence of cracks in the hardened concrete. If the curing time is not long enough or the curing conditions are not controlled properly, it will cause the strength of the concrete to be insufficient, which will also cause cracks in the structure.3. Methods of preventing concrete cracks3.1 Improving the raw materialsIn the production process of concrete, attention should be paid to the quality of raw materials, and the proportion of different materials should be reasonable. The quality of the cement should be strictly controlled, and the particle size and grading of the aggregate should be uniform. The admixture should be properly selected and used to improve the workability and cohesiveness of the concrete.3.2 Improving the mixing processIn the process of mixing, the mixing time and mixing speed should be properly controlled, and the mixing should be uniform to ensure the quality of the concrete. The operation should be standardized to prevent segregation and bleeding, and measures should be taken to reduce the air entrainment rate, so as to increase the density of the concrete.3.3 Improving the placing processIn the process of placing, the pouring time should be appropriate, and the operation should be carried out smoothly to prevent segregation and bleeding. The temperature and humidity of the environment should be kept suitable, and the temperature of the concrete should be controlled to prevent the occurrence of shrinkage cracks.3.4 Improving the curing processIn the process of curing, the concrete should be kept moist and at a suitable temperature, and the curing time should be sufficient to ensure the strength of the concrete. The curing conditions should be properly controlled to prevent the surface of the concrete from drying out and causing shrinkage cracks.4. ConclusionIn the production and use of concrete, the phenomenon of concrete cracking cannot be completely avoided, but through the analysis of the causes of concrete cracking and the adoption of corresponding preventive measures, the occurrence of concrete cracking can be effectively reduced, and the quality of the engineering can be improved. Therefore, it is necessary to carry out scientific and standardized production and construction, control the factors that affect the production and properties of concrete, and prevent the occurrence of concrete cracking.。
混凝土工艺中英文对照外文翻译文献
混凝土工艺中英文对照外文翻译文献混凝土工艺中英文对照外文翻译文献混凝土工艺中英文对照外文翻译文献(文档含英文原文和中文翻译) Concrete technology and developmentPortland cement concrete has clearly emerged as the material of choice for the construction of a large number and variety of structures in the world today. This is attributed mainly to low cost of materials and construction for concrete structures as well as low cost of maintenance.Therefore, it is not surprising that many advancements in concrete technology have occurred as a result of two driving forces, namely the speed of construction and the durability of concrete.During the period 1940-1970, the availability of high early strength portland cements enabled the use of high water content in concrete mixtures that were easy to handle. This approach, however, led to serious problems with durability of structures, especially those subjected to severe environmental exposures.With us lightweight concrete is a development mainly of the last twenty years.Concrete technology is the making of plentiful good concrete cheaply. It includes the correct choice of the cement and the water, and the right treatment of the aggregates. Those which are dug near by and therefore cheap, must be sized, washed free of clay or silt, and recombined in the correct proportions so as to make a cheap concrete which is workable at a low water/cement ratio, thus easily comoacted to a high density and therefore strong.It hardens with age and the process of hardening continues for a long time after the concrete has attained sufficient strength.Abrams’law, perhaps the oldest law of concrete technology, states that the strength of a concrete varies inversely with its water cement ratio. This means that the sand content (particularly the fine sand which needs much water) must be reduced so far as possible. The fact that the sand “drinks” large quantities of water can easily be established by mixing several batches of x kg of cement with y kg of stone and the same amount of water but increasing amounts of sand. However if there is no sand the concrete will be so stiff that it will be unworkable thereforw porous and weak. The same will be true if the sand is too coarse. Therefore for each set of aggregates, the correct mix must not be changed without good reason. This applied particularly to the water content.Any drinkable and many undrinkable waters can be used for making concrete, including most clear waters from the sea or rivers. It is important that clay should be kept out of the concrete. The cement if fresh can usually be chosen on the basis of the maker’s certificates of tensile or crushing tests, but these are always made with fresh cement. Where strength is important , and the cement at the site is old, it should be tested.This stress , causing breakage,will be a tension since concretes are from 9 to 11times as strong in compression as in tension, This stress, the modulus of rupture, will be roughly double the direct tensile breaking stress obtained in a tensile testing machine,so a very rough guess at the conpressive strength can be made by multiplying the modulus of rupture by 4.5. The method can be used in combination with the strength results of machine-crushed cubes or cylinders or tensile test pieces but cannot otherwise be regarded as reliable. With these comparisons,however, it is suitable for comparing concretes on the same site made from the same aggregates and cement, with beams cast and tested in the same way.Extreme care is necessary for preparation,transport,plating and finish of concrete in construction works.It is important to note that only a bit of care and supervision make a great difference between good and bad concrete.The following factors may be kept in mind in concreting works.MixingThe mixing of ingredients shall be done in a mixer as specified in the contract.Handling and ConveyingThe handling&conveying of concrete from the mixer to the place of final deposit shall be done as rapidly as practicable and without any objectionable separation or loss of ingredients.Whenever the length of haul from the mixing plant to the place of deposit is such that the concrete unduly compacts or segregates,suitable agitators shall be installed in the conveying system.Where concrete is being conveyed on chutes or on belts,the free fall or drop shall be limited to 5ft.(or 150cm.) unless otherwise permitted.The concrete shall be placed in position within 30 minutes of its removal from the mixer.Placing ConcreteNo concrete shall be placed until the place of deposit has been thoroughly inspected and approved,all reinforcement,inserts and embedded metal properly security in position and checked,and forms thoroughly wetted(expect in freezing weather)or oiled.Placing shall be continued without avoidable interruption while the section is completed or satisfactory construction joint made.Within FormsConcrete shall be systematically deposited in shallow layers and at such rate as to maintain,until the completion of the unit,a plastic surface approximately horizontal throughout.Each layer shall be thoroughly compacted before placing the succeeding layer.CompactingMethod. Concrete shall be thoroughly compacted by means of suitable tools during and immediately after depositing.The concrete shall be worked around all reinforcement,embedded fixtures,and into the comers of the forms.Every precaution shall be taken to keep the reinforcement and embedded metal in proper position and to prevent distortion.Vibrating. Wherever practicable,concrete shall be internally vibrated within the forms,or in the mass,in order to increase the plasticity as to compact effectively to improve the surface texture and appearance,and to facilitate placing of the concrete.Vibration shall be continued the entire batch melts to a uniform appearance and the surface just starts to glisten.A minute film of cement paste shall be discernible between the concrete and the form and around the reinforcement.Over vibration causing segregation,unnecessary bleeding or formation of laitance shall be avoided.The effect spent on careful grading, mixing and compaction of concrete will be largely wasted if the concrete is badly cured. Curing means keeping the concretethoroughly damp for some time, usually a week, until it has reached the desired strength. So long as concrete is kept wet it will continue to gain strength, though more slowly as it grows older.Admixtures or additives to concrete are materials arematerials which are added to it or to the cement so as to improve one or more of the properties of the concrete. The main types are:1. Accelerators of set or hardening,2. Retarders of set or hardening,3. Air-entraining agents, including frothing or foaming agents,4. Gassing agents,5. Pozzolanas, blast-furnace slag cement, pulverized coal ash,6. Inhibitors of the chemical reaction between cement and aggregate, which might cause the aggregate to expand7. Agents for damp-proofing a concrete or reducing its permeability to water,8. Workability agents, often called plasticizers,9. Grouting agents and expanding cements.Wherever possible, admixtures should be avouded, particularly those that are added on site. Small variations in the quantity added may greatly affect the concrete properties in an undesiraale way. An accelerator can often be avoided by using a rapid-hardening cement or a richer mix with ordinary cement, or for very rapid gain of strength, high-alumina cement, though this is very much more expensive, in Britain about three times as costly as ordinary Portland cement. But in twenty-four hours its strength is equal to that reached with ordinary Portland cement in thirty days.A retarder may have to be used in warm weather when a large quantity of concrete has to be cast in one piece of formwork, and it is important that the concrete cast early in the day does not set before the last concrete. This occurs with bridges when they are cast in place, and the formwork necessarily bends underthe heavy load of the wet concrete. Some retarders permanently weaken the concrete and should not be used without good technical advice.A somewhat similar effect,milder than that of retarders, is obtained with low-heat cement. These may be sold by the cement maker or mixed by the civil engineering contractor. They give out less heat on setting and hardening, partly because they harden more slowly, and they are used in large casts such as gravity dams, where the concrete may take years to cool down to the temperature of the surrounding air. In countries like Britain or France, where pulverized coal is burnt in the power stations, the ash, which is very fine, has been mixed with cement to reduce its production of heat and its cost without reducing its long-term strength. Up to about 20 per cent ash by weight of the cement has been successfully used, with considerable savings in cement costs.In countries where air-entraining cement cement can be bought from the cement maker, no air-entraining agent needs to be mixed in .When air-entraining agents draw into the wet cement and concrete some 3-8 percent of air in the form of very small bubbles, they plasticize the concrete, making it more easily workable and therefore enable the water |cement ratio to be reduced. They reduce the strength of the concrete slightly but so little that in the United States their use is now standard practice in road-building where heavy frost occur. They greatly improve the frost resistance of the concrete.Pozzolane is a volcanic ash found near the Italian town of Puzzuoli, which is a natural cement. The name has been given to all natural mineral cements, as well as to the ash from coal or the slag from blast furnaces, both of which may become cementswhen ground and mixed with water. Pozzolanas of either the industrial or the mineral type are important to civil engineers because they have been added to oridinary Portland cement in proportions up to about 20 percent without loss of strength in the cement and with great savings in cement cost. Their main interest is in large dams, where they may reduce the heat given out by the cement during hardening. Some pozzolanas have been known to prevent the action between cement and certain aggregates which causes the aggregate to expand, and weaken or burst the concrete.The best way of waterproof a concrete is to reduce its permeability by careful mix design and manufacture of the concrete, with correct placing and tighr compaction in strong formwork ar a low water|cement ratio. Even an air-entraining agent can be used because the minute pores are discontinuous. Slow, careful curing of the concrete improves the hydration of the cement, which helps to block the capillary passages through the concrete mass. An asphalt or other waterproofing means the waterproofing of concrete by any method concerned with the quality of the concrete but not by a waterproof skin.Workability agents, water-reducing agents and plasticizers are three names for the same thing, mentioned under air-entraining agents. Their use can sometimes be avoided by adding more cement or fine sand, or even water, but of course only with great care.The rapid growth from 1945 onwards in the prestressing of concrete shows that there was a real need for this high-quality structural material. The quality must be high because the worst conditions of loading normally occur at the beginning of the life of the member, at the transfer of stress from the steel to theconcrete. Failure is therefore more likely then than later, when the concrete has become stronger and the stress in the steel has decreased because of creep in the steel and concrete, and shrinkage of the concrete. Faulty members are therefore observed and thrown out early, before they enter the structure, or at least before it The main advantages of prestressed concrete in comparison with reinforced concrete are :①The whole concrete cross-section resists load. In reinforced concrete about half the section, the cracked area below the neutral axis, does no useful work. Working deflections are smaller.②High working stresses are possible. In reinforced concrete they are not usually possible because they result in severe cracking which is always ugly and may be dangerous if it causes rusting of the steel.③Cracking is almost completely avoided in prestressed concrete.The main disadvantage of prestressed concrete is that much more care is needed to make it than reinforced concrete and it is therefore more expensive, but because it is of higher quality less of it needs to be needs to be used. It can therefore happen that a solution of a structural problem may be cheaper in prestressed concrete than in reinforced concrete, and it does often happen that a solution is possible with prestressing but impossible without it.Prestressing of the concrete means that it is placed under compression before it carries any working load. This means that the section can be designed so that it takes no tension or very little under the full design load. It therefore has theoretically no cracks and in practice very few. The prestress is usually applied by tensioning the steel before the concrete in which it isembedded has hardened. After the concrete has hardened enough to take the stress from the steel to the concrete. In a bridge with abutments able to resist thrust, the prestress can be applied without steel in the concrete. It is applied by jacks forcing the bridge inwards from the abutments. This methods has the advantage that the jacking force, or prestress, can be varied during the life of the structure as required.In the ten years from 1950 to 1960 prestressed concrete ceased to be an experinmental material and engineers won confidence in its use. With this confidence came an increase in the use of precast prestressed concrete particularly for long-span floors or the decks of motorways. Whereever the quantity to be made was large enough, for example in a motorway bridge 500 m kong , provided that most of the spans could be made the same and not much longer than 18m, it became economical to usefactory-precast prestressed beams, at least in industrial areas near a precasting factory prestressed beams, at least in industrial areas near a precasting factory. Most of these beams are heat-cured so as to free the forms quickly for re-use.In this period also, in the United States, precast prestressed roof beams and floor beams were used in many school buildings, occasionally 32 m long or more. Such long beams over a single span could not possibly be successful in reinforced concrete unless they were cast on site because they would have to be much deeper and much heavier than prestressed concrete beams. They would certainlly be less pleasing to the eye and often more expensive than the prestressed concrete beams. These school buildings have a strong, simple architectural appeal and will be a pleasure to look at for many years.The most important parts of a precast prestressed concrete beam are the tendons and the concrete. The tendons, as the name implies, are the cables, rods or wires of steel which are under tension in the concrete.Before the concrete has hardened (before transfer of stress), the tendons are either unstressed (post-tensioned prestressing) or are stressed and held by abutments outside the concrete ( pre-tensioned prestressing). While the concrete is hardening it grips each tendon more and more tightly by bond along its full length. End anchorages consisting of plates or blocks are placed on the ends of the tendons of post-tensioned prestressed units, and such tendons are stressed up at the time of transfer, when the concrete has hardened sufficiently. In the other type of pretressing, with pre-tensioned tendons, the tendons are released from external abutments at the moment of transfer, and act on the concrete through bond or archorage or both, shortening it by compression, and themselves also shortening and losing some tension.Further shortening of the concrete (and therefore of the steel) takes place with time. The concrete is said to creep. This means that it shortens permanently under load and spreads the stresses more uniformly and thus more safely across its section. Steel also creeps, but rather less. The result of these two effects ( and of the concrete shrinking when it dries ) is that prestressed concrete beams are never more highly stressed than at the moment of transfer.The factory precasting of long prestressed concrete beams is likely to become more and more popular in the future, but one difficulty will be road transport. As the length of the beam increases, the lorry becomes less and less manoeuvrable untileventually the only suitable time for it to travel is in the middle of the night when traffic in the district and the route, whether the roads are straight or curved. Precasting at the site avoids these difficulties; it may be expensive, but it has often been used for large bridge beams.混凝土工艺及发展波特兰水泥混凝土在当今世界已成为建造数量繁多、种类复杂结构的首选材料。
建筑施工混凝土裂缝英语论文
建筑施工混凝土裂缝英语论文第一篇：建筑施工混凝土裂缝英语论文Building construction concrete crackAbstract The crack problem of concrete is a widespread existence but again difficult in solve of engineering actual problem, this text carried on a study analysis to a little bit familiar crack problem in the concrete engineering.Keyword:Concrete crackForewordConcrete's ising 1 kind is anticipate by the freestone bone, cement, water and other mixture but formation of the in addition material of quality brittleness not and all material.Because the concrete construction transform with oneself, control etc.a series problem, harden model of in the concrete existence numerous tiny hole, spirit cave and tiny crack, is exactly because these beginning start blemish of existence just make the concrete present one some not and all the characteristic of quality.The tiny crack is a kind of harmless crack and accept concrete heavy, defend Shen and a little bit other use function not a creation to endanger.But after the concrete be subjected to lotus carry, difference in temperature etc.function, tiny crack would continuously of expand with connect, end formation we can see without the aid of instruments of macro view the crack be also the crack that the concrete often say in the engineering.Concrete crack creation of the reason be a lot of and have already transformed to cause of crack:Such as temperature variety, constringency, inflation, the asymmetry sink to sink etc.reason cause of crack;Have outside carry the crack that the function cause;Protected environment not appropriate the cracketc.caused with chemical effect.Want differentiation to treat in the actual engineering, work°out a problem according to the actual circumstance.In the concrete engineering the familiar crack and the prevention1.Stem Suo crack and preventionStem the Suo crack much appear after the concrete protect be over of a period oftime or concrete sprinkle to build to complete behind of around a week.In the cement syrup humidity of evaporate would creation stem Suo, and this kind of constringency is can't negative.Stem Suo crack of the creation be main is because of concrete inside outside humidity evaporate degree dissimilarity but cause to transform dissimilarity of result:The concrete is subjected to exterior condition of influence, surface humidity loss lead quick, transform bigger, inner part degree of humidity variety smaller transform smaller, bigger surface stem the Suo transform to be subjected to concrete inner part control, creation more big pull should dint but creation crack.The relative humidity is more low, cement syrup body stem Suo more big, stem the Suo crack be more easy creation.Stem the Suo crack is much surface parallel lines form or the net shallow thin crack, width many between 0.05-0.2 mm, the flat surface part much see in the big physical volume concrete and follow it more in thinner beam plank short to distribute.Stem Suo crack usually the anti-Shen of influence concrete, cause the durable of the rust eclipse influence concrete of reinforcing bar, under the function of the water pressure dint would creation the water power split crack influence concrete of loading dint etc..Concrete stem the Suo be main with water ash of the concrete ratio, the dosage of the composition, cement of cement, gather to anticipate of thedosage of the property and dosage, in addition etc.relevant.2.The Su constringency crack and preventionSu constringency is the concrete is before condense, surface because of lose water quicker but creation of constringency.The Su constringency crack is general at dry heat or strong wind the weather appear, crack's much presenting in the center breadth, both ends be in the centerthin and the length be different, with each other not coherent appearance.Shorter crack general long 20-30 cm, the longer crack can reach to a 2-3 m, breadth 1-5 mm.It creation of main reason is:The concrete is eventually almost having no strength or strength before the Ning very small, perhaps concrete just eventually Ning but strength very hour, be subjected to heat or compare strong wind dint of influence, the concrete surface lose water to lead quick, result in in the capillary creation bigger negative press but make a concrete physical volume sharply constringency, but at this time the strength of concrete again can't resist itsconstringency, therefore creation cracked.The influence concrete Su constringency open the main factor of crack to have water ash ratio, concrete of condense time, environment temperature, wind velocity, relative humidity...etc..3.Sink to sink crack and preventionThe creation which sink to sink crack is because of the structure foundation soil quality not and evenly, loose soft or return to fill soil dishonest or soak in water but result in the asymmetry sink to decline with the result that;Perhaps because of template just degree shortage, the template propped up to once be apart from big or prop up bottom loose move etc.to cause, especially at winter, the template prop up at jelly soil up, jelly the soil turn jelly empress creation asymmetry to sink todecline and cause concrete structure creation crack.This kind crack many is deep enter or pierce through sex crack, it alignment have something to do with sinking to sink a circumstance, general follow with ground perpendicular or present 30 °s-45 ° Cape direction development, bigger sink to sink crack, usually have certain of wrong, crack width usually with sink to decline quantity direct proportion relation.Crack width under the influence of temperature variety smaller.The foundation after transform stability sink to sink crack also basic tend in stability.4.Temperature crack and preventionTemperature crack much the occurrence is in big surface or difference in temperature variety of the physical volume concrete compare the earth area of the concrete structure.Concrete after sprinkling to build, in the hardening the process, cement water turn a creation a great deal of of water turn hot,.(be the cement dosage is in the 350-550 kg/m 3, each sign square the rice concrete will release a calories of 17500-27500 kJ and make concrete internal thus the temperature rise to reach to 70 ℃ or so even higher)Because the physical volume of concrete be more big, a great deal of of water turn hot accumulate at the concrete inner part but not easy send forth, cause inner part the temperature hoick, but the concrete surface spread hot more quick, so formation inside outside of bigger difference in temperature, the bigger difference in temperature result in inner part and exterior hot the degree of the bulge cold Suo dissimilarity, make concrete surface creation certain of pull should dint.When pullshould dint exceed the anti-of concrete pull strength extreme limit, concrete surface meeting creation crack, this kind of crack much occurrence after the concrete under constructionperiod.In the concrete of under construction be difference in temperature variety more big, perhaps is a concrete to be subjected to assault of cold wave etc., will cause concrete surface the temperature sharply descend, but creation constringency, surface constringency of the concrete be subjected to inner part concrete of control, creation very big of pull should dint but creation crack, this kind of crack usually just in more shallow scope of the concrete surface creation.Conclusion The crack is widespread in the concrete structure existence of a kind of phenomenon, it of emergence not only will lower the anti-Shen of building ability, influence building of usage function, and will cause the rust eclipse of reinforcing bar, the carbonization of concrete, lower the durable of material, influence building of loading ability, so want to carry on to the concrete crack earnest research, differentiation treat, adoption reasonable of the method carry on processing, and at under construction adopt various valid of prevention measure to prevention crack of emergence and development, assurance building and Gou piece safety, stability work.From《CANADIAN JOURNAL OF CIVIL ENGINEERING》建筑施工混凝土裂缝混凝土的裂缝问题是一个普遍存在而又难于解决的工程实际问题，本文对混凝土工程中常见的一些裂缝问题进行了探讨分析。
混凝土施工裂缝原因及防治外文翻译
外文翻译资料Construction cracks in concretecauses and preventionConstruction cracks in concrete, causes and preventionConstruction cracks of concrete reason for the external and internal. The initial mainly refers to the internal defects of concrete in early concrete, its internal hardening process will exist numerous micro-pores, air-pocket and micro cracks, External refers to the load reason: temperature crack, dry shrinkage effect etc. In these, can produce various forms of concrete cracks. To grasp the construction process of raw materials, in pouring process configuration of progress and thickness, grasp timely maintenance work well, which can avoid concrete cracks. A, The cause of the tear1.The initial defects of concreteConcrete is composed of cement, sand aggregate, mixed with water and other materials and formation of heterogeneity brittle materials. In the beginning, because hardened concrete construction and deformation, a series of problems, such as constraint in the concrete shape sclerosis will exist numerous micro-pores, air-pocket and micro cracks of concrete that usually called initial defects. Micro cracks is usually a cracks in the concrete, bearing, and some other function not harm. But under load, temperature of concrete, shrinkage and function, micro cracks will be expanded and connectivity, and finally form the visible cracks of concrete, macroscopic crack, said it was the use of concrete structure, properties and durability of adverse effects.2.The load factorDue to the tensile strength of concrete structure or structures, small as a part of the external effects of stress than concrete tensile strength, will crack. Therefore, the concrete in the load and the load, can produce a crack. To load the crack, can produce by reasonable design and construction to prevent. For the load of crack, due to reasons, it is hardto handle and prevent. The more common than load factors have temperature, dry shrinkage, settling contraction deformation, plastic shrinkage deformation, etc, in these function, can make concrete inside tensile stress.3.Big volume concrete crack formation reasonsMassive concrete cracking reasons can be divided into two types: one is the structural cracks, is caused by external load, 2 it is material of crack is not caused by the changes of deformation and temperature stress and is mainly composed of concrete's shrinkage. This article mainly discussed type materials. One specific reasons are as follows: The temperature stress caused by fracture (temperature crack) temperature cracks in the main reason is caused by temperature difference. Temperature can be divided into three types: early concrete pouring, produce large amounts of the hydration heat, due to the concrete is a poor conductor of heat accumulation in concrete, the hydration heat to send out, often make internal temperatures rise, concrete and reinforced concrete surface temperature for outdoor environment temperature, it is formed, the temperature and temperature inside of condensate in early concrete tensile stress when more than concrete compressive strength, will cause cracking in concrete, In addition, in the dismantling formwork, surface temperature and reduce the temperature caused by fast, and will cause cracking. When the concrete temperature, maximum heat radiates to the minimum temperature, temperature, or use them with the highest temperature difference is the internal temperature, These three temperature will produce temperature crack. In these three temperature, is mainly caused by hydration heat and the temperature.Shrinkage crack contraction there are many causes, including drying shrinkage, plastic shrinkage, shrinkage, carbonation contraction, etc. Here mainly introduces drying shrinkage and plastic shrinkage.After drying shrinkage of concrete sclerosis, in dry environment, the water concrete to the loss caused by inside extroversion, concrete the shrinkage deformation cracks.The plastic shrinkage of cement and concrete in the activity of higher temperature, or in low water-cement condition exacerbate cause craze. When the concrete surface water obviously decreased, lactation evaporation of water cannot get the timely supplements, then concrete is still in a state of plastic, by a concrete surface tension, uneven distribution will appear the cracks of concrete cracks, and further intensify the moisture inside body, and further expansion crack Second, the measures to prevent cracksFrom the above analysis, the crack is mainly caused by temperature difference and contraction, so in order to prevent the cracks of, will maximize reduce temperature and reduce the shrinkage of concrete, specific measures as follows.1. Optimizing raw materials(1)Cement. The cement should be chosen according to the engineering properties, construction condition, climate and other technical requirements, comprehensive consideration, to meet the strength and durability of concrete design requirements. When the choice should be labeled with cement concrete design match the label. For full strength of cement, cement, cement save from the label for concrete label 1.5 to 2 times as appropriate.(2) aggregate. (a) coarse aggregate. The coarse aggregate concrete rubble is close-grained, must have the enough strength, hard to expand the coarse aggregate size. To ensure the concrete pouring dao close-grained, coarse aggregate maximum diameter less than the minimum size of the structural sections 1/4, also not greater than the minimum distance between steel net for thickness 3/4, in 10 centimeters and concrete, allowing adoptsmaximum diameter 1 1/2 of the aggregate number, but it shall not exceed 25%. (b) fine aggregate. Sand particle gradation of technical properties of concrete influence, requests the porosity and total surface area small, small need total surface on the surface of the gravel package will reduce quantity of cement slurry, can reduce the dosage of cement hydration heat, reduce to prevent cracks. On the other hand is to control the hydraulic sand, the content of 5% in concrete, "the contraction deformation, the hydraulic and larger crack, fine aggregate to use clean in the sand.(3) admixtures. (a) water-reducing agent. Jianshuiji belongs to the surface active substances, is a kind of cement dispersant. Its main function of improving concrete workability, reduce the consumption of concrete mixture, reduce water-cement ratio increases, and improve the liquidity of concrete strength of concrete or keep in concrete cement strength must decrease, while the water-cement ratio, the dosage of cement to prevent cracking is reduced. (b) retarder. Retarder is delaying the role of concrete exothermic peak time, 2 it is to improve workability, and reduce the loss of collapsbillity. (c) air-entraining agent. In the application of concrete air-entraining agent for improving the concrete workability, can pump, improving the concrete durability is very favorable. In a certain extent increase anti-cracking performance of concrete.(4) mass concrete chooses raw materials should pay attention to the following:①The coarse aggregate gradation, appropriate USES continuous fine aggregate ZhongSha should be adopted.②Admixtures appropriate USES retarder, water-reducer, Admixtures appropriate USES fly ash, slag powder etc.③In mass concrete strength of concrete and the slump and the requirements of the premise, should improve mixing and aggregate content,in order to reduce the dosage of cement concrete alone.④ Should try to choose cement hydration heat low, setting time is long, the cement, low thermal Portland cement slag silicate cement, cement, slag dam Portland cement, coal ash Portland cement, volcanic gray Portland cement, etc.However, the slag cement hydration heat low water cement ratio of chromatography in other large, casting lots of water surface layer. This phenomenon is not only affect lactation water, also influence the construction speed and quality of construction. Because the water gathered in separation between the two casting concrete surface layer, change, and water-cement ratio in the water and took out some of the mortar, thus forming a layer of interlining content, destroyed the cohesive force of concrete and holistic. The size of the water concrete lactation with water water, water, lactation; And with the temperature, water separation of time with temperature completely and shortening, In addition, also with the composition and fineness of cement. Therefore, in selecting slag cement should be chosen when the varieties, and lactation shall be adding water-reducing agent in concrete, to reduce the consumption. During construction, should be in water or mixing some tomography uniform rolling cement casting in water, with 3-degrees vibration compaction, continue again after a concrete casting.2.the reasonable construction method(1) The concrete mixing and transportation. (a) white, accurate grasp of concrete proportion, especially the strict control of water consumption, the determination of sand. Records of every block water cement, sand and gravel, specific quantity, the application must be accurate to scale, by mixing. Good control of concrete slump and general shoulds not be too big, in 120 ± 20 mm. To minimize the mouth 3 concrete temperature. (b) concrete mixing in a storehouse after good transportprocess, to prevent to produce separation, lactation water, mortar loss should shorten transportation time, concrete loading not too full. (2)Concrete pouring and open mode. Pouring process may be close-grained, vibration to vibration time should be uniform in surface functional plasma advisable, uniform spacing, vibrating force scope affected overlap 1/2 advisable, after casting, compaction, surface must, in order to prevent the surface crack. Try to avoid in the solar radiation, high time due to the needs of the project if pouring in summer construction, avoid noon pouring temperature period, try to arrange at night. Time should be removed, according to air temperature and strength. In the actual temperature curing of the concrete conditions of strength, strength design of concrete center and 75%, the lowest temperature control surface in 25 degrees Celsius, expected the concrete surface temperature drop more than 9 degrees Celsius above does not allow removed.(3) Do surface insulation protection of mass concrete temperature crack, is mainly caused by excessive temperature. Concrete pouring, due to internal heat faster, more surface temperature will form the internal and external surface by internal restraint, contraction, but the tensile stress, not more than usually have small tensile strength and the concrete cracks. But if the air raid, or by excessive ventilation cooling, make the surface temperature will easily lead to excessive temperature crack in the concrete, and so on, especially after dismantling formwork, low season in the immediate surface protection. To prevent excessive temperature crack, cause surface. In addition, the average day temperature in 2 ~ 3d consecutive decline not less than 6 ~ 8 degrees Celsius, 28d age concrete surface must surface within the protection.(4) Of the mass concrete casting:Construction scheme, besides should satisfy each place of concrete in early before a new concrete are covered and rammed finished outside,still should consider structure size, steel pipe, buries the bolts and leave, concrete and hydration heat supply, the influence of factors such as the commonly used method has the following kinds:Comprehensive stratified:In the first layer after pouring all comprehensive casting, casting back second, should make the first layer of concrete yet, so early, continuous casting until completion by far. Using this scheme, applicable to the general structure of planar size shoulds not be too big, when construction from the short side began to push along the long side, is more appropriate. When necessary, can be divided into two sections from middle to both ends to or from the middle and construction.Section 2 layer:Concrete casting, starting from scratch, casting a certain distance to the second floor, so after pouring in other layers on casting. Due to the total number of layers, therefore, after the first layer top pouring concrete yet at the end of the beginning of the second period, and can turn from layered casting. This scheme is applicable to units within the time required, the supply of concrete less like the first option on that. This scheme is applicable to structure is too big and thickness of large area or length.Incline stratified:Requirements of slope not greater than cant 1/3, applicable to greatly exceed the length of the structure of the thickness of the three times. From the bottom layer of concrete casting, gradually move.3.maintenance measuresMaintenance of mass concrete construction is a vital work. Maintain proper maintenance is mainly to control temperature and humidity, temperature, promote concrete outside the normal development of the strength of concrete and prevent the cracks of concrete and development.According to the specific circumstances of should as far as possible much maintenance period of time, after dismantling formwork should immediately, covering protection to prevent recent climate, sudden cold temperature, prevent and control in early concrete cracks and medium. The massive concrete curing, not only to satisfy the need that still should increase by artificial temperature control, due to temperature caused by deformation of the concrete cracking. After the completion of the concrete curing time to keep the concrete surface spraying maintenance, such as reducing often humid heat outside pour cans, and prevent dry crack and promote the stable growth of concrete strength. In general 18h 12 ~ after pouring in immediately start maintenance, maintenance time not less than 28d or design age.4 CooledIf in the high-temperature seasonal construction, should be in early general refrigeration adopted to reduce the water temperature, but the peak of concrete, water cannot too long, for a long time can cause excessive temperature range of temperature stress caused by large. In order to cut inside and outside, still should temperature in summer jiamoqiuchu undertake metaphase is cooled by water, river, general middle water lasted about two months. Later, water is made concrete cylindrical blocks the necessary measures to juncture grouting, generally USES water and cooling water through the combination scheme.Third, the conclusionConcrete crack, especially large volume concrete crack is currently scholars and engineering is an important problem of attention, through the above analysis, the material of mass concrete crack is mainly composed of temperature stress and concrete's shrinkage, the author thinks carefully select material, and in the use of reasonable construction method, can effectively prevent the cracks.混凝土施工裂缝原因及防治混凝土施工裂缝原因不外乎外因和内因。
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中英文对照外文翻译(文档含英文原文和中文翻译)Building construction concrete crack ofprevention and processingAbstractThe crack problem of concrete is a widespread existence but again difficult in solve of engineering actual problem, this text carried on a study analysis to a little bit familiar crack problem in the concrete engineering, and aim at concrete the circumstance put forward some prevention, processing measure.Keyword:Concrete crack prevention processingForewordConcrete's ising 1 kind is anticipate by the freestone bone, cement, water and other mixture but formation of the in addition material of quality brittleness not and all material.Because the concrete construction transform with oneself, control etc. a series problem, harden model of in the concrete existence numerous tiny hole, spirit cave and tiny crack, is exactly because these beginning start blemish of existence just make the concrete present one some not and all the characteristic of quality.The tiny crack is a kind of harmless crack and accept concrete heavy, defend Shen and a little bit other use function not a creation to endanger.But after the concrete be subjected to lotus carry, difference in temperature etc. function, tiny crack would continuously of expand with connect, end formation we can see without the aid of instruments of macro view the crack be also the crack that the concrete often say in the engineering.Concrete building and Gou piece usually all take sewer to make of, because of crack of existence and development usually make inner part of reinforcing bar etc. material creation decay, lower reinforced concrete material of loading ability, durable and anti- Shen ability, influence building of external appearance, service life, severity will threat arrive people's life and property safety.A lot of all of crash of engineerings is because of the unsteady development of the crack withthe result that.Modern age science research with a great deal of of the concrete engineering practice certificate, in the concrete engineering crack problem is ineluctable, also acceptable in certainly of the scope just need to adopt valid of measure will it endanger degree control at certain of scope inside.The reinforced concrete norm is also explicit provision:Some structure at place of dissimilarity under the condition allow existence certain the crack of width.But at under construction should as far as possible adopt a valid measure control crack creation, make the structure don't appear crack possibly or as far as possible decrease crack of amount and width, particularly want to as far as possible avoid harmful crack of emergence, insure engineering quality thus.Concrete crack creation of the reason be a lot of and have already transformed to cause of crack:Such as temperature variety, constringency, inflation, the asymmetry sink to sink etc. reason cause of crack;Have outside carry the crack that the function cause;Protected environment not appropriate the crack etc. caused with chemical effect.Want differentiation to treat in the actual engineering, work°out a problem according to the actual circumstance.In the concrete engineering the familiar crack and the prevention1.Stem Suo crack and preventionStem the Suo crack much appear after the concrete protect beover of a period of time or concrete sprinkle to build to complete behind of around a week.In the cement syrup humidity of evaporate would creation stem Suo, and this kind of constringency is can't negative.Stem Suo crack of the creation be main is because of concrete inside outside humidity evaporate degree dissimilarity but cause to transform dissimilarity of result:The concrete is subjected to exterior condition of influence, surface humidity loss lead quick, transform bigger, inner part degree of humidity variety smaller transform smaller, bigger surface stem the Suo transform to be subjected to concrete inner part control, creation more big pull should dint but creation crack.The relative humidity is more low, cement syrup body stem Suo more big, stem the Suo crack be more easy creation.Stem the Suo crack is much surface parallel lines form or the net shallow thin crack, width many between 0.05-0.2 mm, the flat surface part much see in the big physical volume concrete and follow it more in thinner beam plank short to distribute.Stem Suo crack usually the anti- Shen of influence concrete, cause the durable of the rust eclipse influence concrete of reinforcing bar, under the function of the water pressure dint would creation the water power split crack influence concrete of loading dint etc..Concrete stem the Suo be main with water ash of the concrete ratio, the dosage of the composition, cement of cement, gather to anticipate of the dosage of the property and dosage, in addition etc. relevant.Main prevention measure:While being to choose to use the constringency quantity smaller cement, general low hot water mire and powder ash from stove cement in the adoption, lower the dosage of cement.Two is a concrete of stem the Suo be subjected to water ash ratio of influence more big, water ash ratio more big, stem Suo more big, so in the concrete match the ratio the design should as far as possible control good water ash ratio of choose to use, the Chan add in the meantime accommodation of reduce water.Three is strict control concrete mix blend with under construction of match ratio, use of concrete water quantity absolute can't big in match ratio design give settle of use water quantity.Four is the earlier period which strengthen concrete to protect, and appropriate extension protect of concrete time.Winter construction want to be appropriate extension concrete heat preservation to overlay time, and Tu2 Shua protect to protect.Five is a constitution the accommodation is in the concrete structure of the constringency sew.2.The Su constringency crack and preventionSu constringency is the concrete is before condense, surface because of lose water quicker but creation of constringency.The Su constringency crack is general at dry heat or strong wind the weather appear, crack's much presenting in the center breadth, both ends be in the centerthin and the length be different, with each other not coherentappearance.Shorter crack general long 20-30 cm, the longer crack can reach to a 2-3 m, breadth 1-5 mm.It creation of main reason is:The concrete is eventually almost having no strength or strength before the Ning very small, perhaps concrete just eventually Ning but strength very hour, be subjected to heat or compare strong wind dint of influence, the concrete surface lose water to lead quick, result in in the capillary creation bigger negative press but make a concrete physical volume sharply constringency, but at this time the strength of concrete again can't resist its constringency, therefore creation cracked.The influence concrete Su constringency open the main factor of crack to have water ash ratio, concrete of condense time, environment temperature, wind velocity, relative humidity...etc..Main prevention measure:One is choose to use stem the Suo value smaller higher Huo sour salt of the earlier period strength or common the Huo sour brine mire.Two is strict the control water ash ratio, the Chan add to efficiently reduce water to increment the collapse of concrete fall a degree and with easy, decrease cement and water of dosage.Three is to sprinkle before building concrete, water basic level and template even to soak through.Four is in time to overlay the perhaps damp grass mat of the plastics thin film, hemp slice etc., keep concrete eventually before the Ning surface is moist, perhaps spray to protect etc. to carry on protect in the concrete surface.Five is in the heatand strong wind the weather to want to establish to hide sun and block breeze facilities, protect in time.3.Sink to sink crack and preventionThe creation which sink to sink crack is because of the structure foundation soil quality not and evenly, loose soft or return to fill soil dishonest or soak in water but result in the asymmetry sink to decline with the result that;Perhaps because of template just degree shortage, the template propped up to once be apart from big or prop up bottom loose move etc. to cause, especially at winter, the template prop up at jelly soil up, jelly the soil turn jelly empress creation asymmetry to sink to decline and cause concrete structure creation crack.This kind crack many is deep enter or pierce through sex crack, it alignment have something to do with sinking to sink a circumstance, general follow with ground perpendicular or present 30 °s-45 ° Cape direction development, bigger sink to sink crack, usually have certain of wrong, crack width usually with sink to decline quantity direct proportion relation.Crack width under the influence of temperature variety smaller.The foundation after transform stability sink to sink crack also basic tend in stability.Main prevention measure:One is rightness loose soft soil, return to fill soil foundation a construction at the upper part structure front should carry on necessity of Hang solid with reinforce.Two is thestrength that assurance template is enough and just degree, and prop up firm, and make the foundation be subjected to dint even.Three is keep concrete from sprinkle infusing the foundation in the process is soak by water.Four is time that template tore down to can't be too early, and want to notice to dismantle a mold order of sequence.Five is at jelly soil top take to establish template to notice to adopt certain of prevention measure.4.Temperature crack and preventionTemperature crack much the occurrence is in big surface or difference in temperature variety of the physical volume concrete compare the earth area of the concrete structure.Concrete after sprinkling to build, in the hardening the process, cement water turn a creation a great deal of of water turn hot, .(be the cement dosage is in the 350-550 kg/m 3, each sign square the rice concrete will release a calories of 17500-27500 kJ and make concrete internal thus the temperature rise to reach to 70 ℃or so even higher)Because the physical volume of concrete be more big, a great deal of of water turn hot accumulate at the concrete inner part but not easy send forth, cause inner part the temperature hoick, but the concrete surface spread hot more quick, so formation inside outside of bigger difference in temperature, the bigger difference in temperature result in inner part and exterior hot the degree of the bulge cold Suo dissimilarity, makeconcrete surface creation certain of pull should dint.When pull should dint exceed the anti- of concrete pull strength extreme limit, concrete surface meeting creation crack, this kind of crack much occurrence after the concrete under construction period.In the concrete of under construction be difference in temperature variety more big, perhaps is a concrete to be subjected to assault of cold wave etc., will cause concrete surface the temperature sharply descend, but creation constringency, surface constringency of the concrete be subjected to inner part concrete of control, creation very big of pull should dint but creation crack, this kind of crack usually just in more shallow scope of the concrete surface creation.The alignment of the temperature crack usually none settle regulation, big area structure the crack often maneuver interleave;The size bigger structure of the beam plank length, the crack run parallel with short side more;Thorough with pierce through sex of temperature crack general and short side direction parallelism or close parallelism, crack along long side cent the segment appear, in the center more airtight.Crack width the size be different, be subjected to temperature variety influence more obvious, winter compare breadth, summer more narrow.The concrete temperature crack that the heat inflation cause is usually in the center the thick both ends be thin, but cold Suo crack of thick thin variety not too obvious.The emergence of the this kind crackwill cause the rust eclipse of reinforcing bar, the carbonization of concrete, the anti- jelly which lower concrete melt, anti- tired and anti- Shen ability etc..Main prevention measure:One is as far as possible choose to use low hot or medium hot water mire, like mineral residue cement, powder ash from stove cement...etc..Two is a decrease cement dosage, cement dosage as far as possible the control is in the 450 kg/m 3 following.Three is to lower water ash ratio, water ash of the general concrete ratio control below 0.6.Four is improvement the bone anticipate class to go together with, the Chan add powder ash from stove or efficiently reduce water etc. to come to reduce cement dosage and lower water to turn hot.Five is an improvement concrete of mix blend to process a craft, lower sprinkle of concrete to build temperature.Six is the in addition that the Chan add a have of fixed amount to reduce water and increase Su, slow Ning etc. function in the concrete, improvement the concrete mix to match a thing of mobility, protect water, lower water to turn hot, postpone hot Feng of emergence time.Seven is the heat season sprinkle to build can the adoption take to establish to hide sun plank etc. assistance measure control concrete of Wen Sheng, lower to sprinkle temperature of build the concrete.Eight is the temperature of big physical volume concrete should the dint relate to structure size, concrete structure size more big, temperature should dint more big, sowant reasonable arrangement construction work preface, layering, cent the piece sprinkle to build, for the convenience of in spread hot, let up control.Nine is at great inner part constitution of the physical volume concrete cool off piping, cold water perhaps cold air cool off, let up concrete of inside outside difference in temperature.Ten is the supervision which strengthen concrete temperature, adopt to cool off in time, protection measure.11 is to reserve temperature constringency to sew.12 is to let up to control, sprinkle proper before building concrete in the Ji rock and old concrete top build a 5 mm or so sand mat a layer or usage asphalt etc. material Tu2 Shua.13 is to strengthen concrete to protect, the concrete after sprinkle build use moist grass Lian in time, hemp slice's etc. overlay, and attention sprinkle water to protect, appropriate extension protect time, assurance the concrete surface be slow-moving cool off.At the cold season, concrete surface should constitution heat preservation measure, in order to prevent cold wave assault.14 is the allocation be a little amount in the concrete of reinforcing bar perhaps add fiber material concrete of temperature crack control at certain of scope inside.5.Crack and prevention that the chemical reaction causeAlkali bone's anticipating the crack that reaction crack and reinforcing bar rust eclipse cause is the most familiar in the reinforced concrete structure of because of chemical reaction but cause of crack.The concrete blend a future reunion creation some alkalescence ion, these ion with some activity the bone anticipate creation chemical reaction and absorb surroundings environment in of water but the physical volume enlarge, make concrete crisp loose, inflation open crack.In this kind of crack general emergence concrete structure usage period, once appear very difficult remediable, so should at under construction adopt valid the measure carry on prevention.Main of prevention measure:While being to choose to anticipate with the alkali activity small freestone bone.Two is the in addition which choose to use low lye mire with low alkali or have no alkali.Three is the Chan which choose to use accommodation with anticipate to repress an alkali bone to anticipate reaction.Because the concrete sprinkle to build, flap Dao bad perhaps is a reinforcing bar protection layer thinner, the harmful material get into concrete to make reinforcing bar creation rust eclipse, the reinforcing bar physical volume of the rust eclipse inflation, cause concrete bulge crack, the crack of this kind type much is a crack lengthways, follow the position of reinforcing bar ually of prevent measure from have:One is assurance reinforcing bar protection the thickness of the layer.Two is a concrete class to go together with to want good.Three is a concrete to sprinkle to note and flap Dao airtight solid.Four is a reinforcing bar surface layer Tu2 Shua antisepsis coating.Crack processingThe emergence of the crack not only would influence structure of whole with just degree, return will cause the rust eclipse of reinforcing bar, acceleration concrete of carbonization, lower durable and anti- of concrete tired, anti- Shen ability.Therefore according to the property of crack and concrete circumstance we want differentiation to treat, in time processing, with assurance building of safety usage.The repair measure of the concrete crack is main to have the following some method:Surface repair method, infuse syrup, the Qian sew method, the structure reinforce a method, concrete displacement method, electricity chemistry protection method and imitate to living from heal method.Surface repair the method be a kind of simple, familiar of repair method, it main be applicable to stability and to structure loading the ability don't have the surface crack of influence and deep enter crack of processing.The processing measure that is usually is a surface in crack daubery cement syrup, the wreath oxygen gum mire or at concrete surface Tu2 Shua paint, asphalt etc. antisepsis material, at protection of in the meantime for keeping concrete from continue under the influence of various function to open crack, usually can adoption the surface in crack glue to stick glass fiber cloth etc. measure.1, infuse syrup, the Qian sew methodInfuse a syrup method main the concrete crack been applicable to have influence or have already defend Shen request to the structure whole of repair, it is make use of pressure equipments gum knot the material press into the crack of concrete, gum knot the material harden behind and concrete formation one be whole, thus reinforce of purpose.The in common use gum knot material has the cement the syrup, epoxy, A Ji C Xi sour ester and gather ammonia ester to equalize to learn material.The Qian sew a method is that the crack be a kind of most in common use method in, it usually is follow the crack dig slot, the Qian fill Su in the slot or rigid water material with attain closing crack of purpose.The in common use Su material has PVC gum mire, plastics ointment, the D Ji rubber etc.;In common use rigid water material is the polymer cement sand syrup.2, the structure reinforce a methodWhen the crack influence arrive concrete structure of function, will consideration adopt to reinforce a method to carry on processing to the concrete structure.The structure reinforce medium in common use main have the following a few method:The piece of enlargement concrete structure in every aspect accumulate, outside the Cape department of the Gou piece pack type steel, adoption prepare should the dint method reinforce, glue to stick steel plate to reinforce, increaseto establish fulcrum to reinforce and jet the concrete compensation reinforce.3, concrete displacement methodConcrete displacement method is processing severity damage concrete of a kind of valid method, this method be first will damage of the concrete pick and get rid of, then again displacement go into new of concrete or other material.The in common use displacement material have:Common concrete or the cement sand syrup, polymer or change sex polymer concrete or sand syrup.4, the electricity chemistry protection methodThe electricity chemistry antisepsis is to make use of infliction electric field in lie the quality of electricity chemical effect, change concrete or reinforced concrete the environment appearance of the place, the bluntness turn reinforcing bar to attain the purpose of antisepsis.Cathode protection method, chlorine salt's withdrawing a method, alkalescence to recover a method is a chemistry protection method in three kinds of in common use but valid method.The advantage of this kind of method is a protection method under the influence of environment factor smaller, apply reinforcing bar, concrete of long-term antisepsis, since can used for crack structure already can also used for new set up structure.5, imitate to living from legal moreImitate to living from heal the method be a kind of new crack treatment, its mimicry living creature organization secrete a certain material towards suffering wound part auto, but make the wound part heal of function, join some and special composition(such as contain to glue knot of the liquid Xin fiber or capsule) in the concrete of the tradition the composition, at concrete inner part formation the intelligence type imitate to living from heal nerve network system, be the concrete appear crack secrete a parts of liquid Xin fiber can make the crack re- heal.ConclusionThe crack is widespread in the concrete structure existence of a kind of phenomenon, it of emergence not only will lower the anti- Shen of building ability, influence building of usage function, and will cause the rust eclipse of reinforcing bar, the carbonization of concrete, lower the durable of material, influence building of loading ability, so want to carry on to the concrete crack earnest research, differentiation treat, adoption reasonable of the method carry on processing, and at under construction adopt various valid of prevention measure to prevention crack of emergence and development, assurance building and Gou piece safety, stability work.建筑施工混凝土裂缝的预防与处理混凝土的裂缝问题是一个普遍存在而又难于解决的工程实际问题，本文对混凝土工程中常见的一些裂缝问题进行了探讨分析，并针对具体情况提出了一些预防、处理措施。