混凝土工艺中英文对照外文翻译文献
建筑施工混凝土裂缝处理中英文对照外文翻译文献
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。
建筑工程英标规范(混凝土)中英文
SECTION: 2 第2章混凝土PART 1 GENERAL 第1节总则1 DESCRIPTION 说明All concrete work is governed by this Section.所有混凝土工程受本章的管理。
Work Included: Provide all cast—in-place concrete，complete and in place，as required by the Work，specified hereinon the drawings and specifications. 包括的工作：按照图纸上规定的工作和相关标准要求，完整而到位地提供所有现浇混凝。
RELATED WORK：有关工作1 General Requirements一般要求2 Material 材料3 Concrete Mix 混凝土配合比4 Construction Requests 施工要求1.1. GENERAL REQUIREMENTS：一般要求1.1.1. Concrete shall be batched only with approved materials, approved mix designs，and atapproved facilities。
只能使用批准的材料、批准的配合比设计和在批准的设施内对混凝土进行配料.1.1.2. The Contractor shall define the method of design of the mix，by reference to arecognised published design method. 承包商应通过参考认可的设计方法确定配合比设计.1.1.3. Plant trials shall be carried out for each grade and type of concrete in the contract, 你unless approved otherwise by the Engineer. 除非监理工程师另有批准，应对每种标号和种类的混凝土进行工厂试验。
新拌混凝土的性能中英文资料外文翻译文献
新拌混凝土的性能中英文资料外文翻译文献(文档含英文原文和中文翻译)Properties of Fresh ConcreteFresh concrete is a mixture of water, cement, aggregate and admixture (if any). After mixing, operations such as transporting, placing, compacting and finishing of fresh concrete can all considerably affect the properties of hardened concrete. It is important that the constituent materials remain uniformly distributed within the concrete mass during the various stages of its handling and that full compaction is achieved. When either of these conditions is not satisfied the properties of the resulting hardened concrete, for example, strength and durability, are adversely affected.The characteristics of fresh concrete which affect full compaction are its consistency, mobility and compactability. In concrete practice these are often collectively known as workability. The ability of concrete to maintain its uniformity is governed by its stability, which depends on its consistency and its cohesiveness. Since the methods employed for conveying, placing and consolidatingd a concrete mix, as well as the nature of the section to be cast, may vary from job to job it follows that the corresponding workability and stability requirements will also vary. The assessment of the suitability of a fresh concrete for a particular job will alwaysto some extent remain a matter of personal judgment.In spite of its importance, the behaviour of plastic concrete often tends to be overlooked. It is recommended that students should learn to appreciate the significance of the various characteristics of concrete in its plastic state and know how these may alter during operations involved in casting a concrete structure.13.1 WorkabilityWorkability of concrete has never been precisely defined. For practical purposes it generally implies the ease with which a concrete mix can be handled from the mixer to its finally compacted shape. The three main characteristics of the property are consistency, mobility and compactability. Consistency is a measure of wetness or fluidity. Mobility defines the ease with which a mix can flow into and completely fill the formwork or mould. Compactability is the ease with which a given mix can be fully compacted, all the trapped air being removed. In this context the required workability of a mix depends not only on the characteristics and relative proportions of the constituent materials but also on (1) the methods employed for conveyance and compaction, (2) the size, shape and surface roughness of formwork or moulds and (3) the quantity and spacing of reinforcement.Another commonly accepted definition of workability is related to the amount of useful internal work necessary to produce full compaction. It should be appreciated that the necessary work again depends on the nature of the section being cast. Measurement of internal work presents many difficulties and several methods have been developed for this purpose but none gives an absolute measure of workability.The tests commonly used for measuring workability do not measure the individual characteristics (consistency, mobility and compactability) of workability. However, they do provide useful and practical guidance on the workability of a mix. Workability affects the quality of concrete and has a direct bearing on cost so that, for example, an unworkable concrete mix requires more time and labour for full compaction. It is most important that a realistic assessment is made of the workability required for given site conditions before any decision is taken regarding suitable concrete mix proportions.13.2 Measurement of WorkabilityThree tests widely used for measuring workability are the slump, compacting factorand V-B consistometer tests (figure 13.1). These are standard tests in the United Kingdom and are described in detail in BS 1881: Part 2. Their use is also recommended in CP 110: Part 1. It is important to note that there is no single relationship between the slump, compacting factor and V-B results for different concretes. In the following sections the salient features of these tests together with their merits and limitations are discussed.Slump TestThis test was developed by Chapman in the United States in 1913. A 300 mm high concrete cone, prepared under standard conditions (BS 1881: Part 2) is allowed to subside and the slump or reduction in height of the cone is taken to be a measure of workability. The apparatus is inexpensive, portable and robustd and is the simplest of all the methods employed for measuring workability. It is not surprising that, in spite of its several limitations, the slump test has retained its popularity.Figure 13.1 Apparatus for workability measurement: (a) slump cone, (b) compacting factor and(c) V-B consistometerThe test primarily measures the consistency of plastic concrete and although it is difficult to see any significant relationship between slump and workability as defined previously, it is suitable for detecting changes in workability. For example, an increase in the water content or deficiency in the proportion of fine aggregate results in an increase in slump. Although the test is suitable for quality-controlpurposes it should be remembered that it is generally considered to be unsuitable formix design since concretes requiring varying amounts of work for compaction can have similar numerical values of slump. The sensitivity and reliability of the test for detecting variation in mixes of different workabilities is largely dependent on its sensitivity to consistency. The test is not suitable for very dry or wet mixes. For very dry mixes, with zero or near-zero slump, moderate variations in workability do not result in measurable changes in slump. For wet mixes, complete collapse of the concrete produces unreliable values of slump.Figure 13.2 Three main types of slumpThe three types of slump usually observed are true slump, shear slump and collapse slump, as illustrated in figure 13.2. A true slump is observed with cohesive and rich mixes for which the slump is generally sensitive to variations in workability.A collapse slump is usually associated with very wet mixes and is generally indicative of poor quality concrete and most frequently results from segregation of its constituent materials. Shear slump occurs more often in leaner mixes than in rich ones and indicates a lack of cohesion which is generally associated with harsh mixes (low mortar content). whenever a shear slump is obtained the test should be repeated and, if persistent, this fact should be recorded together with test results, because widely different values of slump can be obtained depending on whether the slump is of true or shear form.The standard slump apparatus is only suitable for concretes in which the maximum aggregate size does not exceed 37.5 mm. It should be noted that the value of slump changes with time after mixing owing to normal hydration processes and evaporation of some of the free water, and it is desirable therefore that tests are performed within a fixed period of time.Compacting Factor TestThis test, developed in the United Kingdom by Glanville et al. (1947), measures the degree of compaction for a standard amount of work and thus offers a direct and reasonably reliable assessment of the workability of concrete as previously defined. The apparatus is a relatively simple mechanical contrivance (figure 13.1) and is fully described in BS 1881: Part 2. The test requires measurement of the weights of the partially and fully compacted concrete and the ratio of the partially compacted weight to the fully compacted weight, which is always less than 1, is known as the compacting factor. For the normal range of concretes the compacting factor lies between 0.80 and 0.92. The test is particularly useful for drier mixes for which the slump test is not satisfactory. The sensitivity of the compacting factor is reduced outside the normal range of workability and is generally unsatisfactory for compacting factors greater than 0.92.It should also be appreciated that, strictly speaking, some of the basic assumptions of the test are not correct. The work done to overcome surface friction of the measuring cylinder probably varies with the characteristics of the mix. It has been shown by Cusens (1956) that for concretes with very low workability the actual work required to obtain full compaction depends on the richness of a mix while the compacting factor remains sensibly unaffected. Thus it follows that the generally held belief that concretes with the same compacting factor require the same amount of work for full compaction cannot always be justified. One further point to note is that the procedure for placing concrete in the measuring cylinder bears no resemblance to methods commonly employed on the site. As in the slump test, the measurement of compacting factor must be made within a certain specified period. The standard apparatus is suitable for concrete with a maximum aggregate size of up to 37.5 mm. V-B Consistometer TestThis test was developed in Sweden by B a hrner (1940) (see figure 13.1). Although generally regarded as a test primarily used in research its potential is now more widely acknowledged in industry and the test is gradually being accepted. In this test (BS 1881: Part 2) the time taken to transform, by means of vibration, a standard cone of concrete to a compacted flat cylindrical mass is recorded. This is known as the V-B time, in seconds, and is stated to the nearest 0.5 s. Unlike the two previous tests, the treatment of concrete in this test is comparable to the method of compacting concrete in practice. Moreover, the test is sensitive to change inconsistency, mobility and compactability, and therefore a reasonable correlation between the test results and site assessment of workability can be expected.The test is suitable for a wide range of mixes and, unlike the slump and compacting factor tests, it is sensitive to variations in workability of very dry and also air-entrained concretes. It is also more sensitive to variation in aggregate characteristics such as shape and surface texture. The reproducibility of results is good. As for other tests its accuracy tends to decrease with increasing maximum size of aggregate; above 19.0 mm the test results become somewhat unreliable. For concretes requiring very little vibration for compaction the V-B time is only about 3 s. Such results are likely to be less reliable than for larger V-B times because of the difficulty in estimating the time of the end point (concrete in contact withd the whole of the underside of the plastic disc). At the other end of the workability range, such as with very dry mixes, the recorded V-B times are likely to be in excess of their true workability since prolonged vibration is required to remove the entrapped air bubbles under the transparent disc. To overcome this difficulty an automatic device which records the vertical settlement of the disc with respect to time can be attached to the apparatus. This recording device can also assist in eliminating human error in judging the end point. The apparatus for the V-B test is more expensive than that for the slump and compacting factor tests, requiring an electric power supply and greater experience in handling; all these factors make it more suitable for the precast concrete industry and ready-mixed concrete plants than for general site use.13.3 Factors Affecting WorkabilityVarious factors known to influence the workability of a freshly mixed concrete are shown in figure 13.3. From the following discussion it will be apparent that a change in workability associated with the constituent materials is mainly affected by water content and specific surface of cement and aggregate.Cement and WaterFigure 13.3 Factors affecting workability of fresh conreteTypical relationships between the cement-water ratio (by volume) and the volume fraction of cement for different workabilities are shown in figure 15.5. The change in workability for a given change in cement-water ratio is greater when the water content is changed than when only the cement content is changed. In general theeffect of the cement content is greater for richer mixes. Hughes (1971) has shown that similar linear relationships exist irrespective of the properties of the constituent materials.For a given mix, the workability of the concrete decreases as the fineness of the cement increases as a result of the increased specific surface, this effect being more marked in rich mixtures. It should also be noted that the finer cements improve the cohesiveness of a mix. With the exception of gypsum, the composition of cement has no apparent effect on workability. Unstable gypsum is responsible for false set, which can impair workability unless prolonged mixing or remixing of the fresh concrete is carried out. Variations in quality of water suitable for making concrete have no significant effect on workability.AdmixturesThe principal admixtures affecting improvement in the workability of concrete are water-reducing and air-entraining agents. The extent of the increase in workability is dependent on the type and amount of admixture used and the general characteristics of the fresh concrete.Workability admixtures are used to increase workability while the mix proportions are kept constant or to reduce the water content while maintaining constant workability. The former results in a slight reduction in concrete strength.Air-entraining agents are by far the most commonly used workability admixtures because they also improve both the cohesiveness of the plastic concrete and the frost resistance of the resulting hardened concrete. Two points of practical importance concerning air-entrained concrete are that for a given amount of entrained air, the increase in workability tends to be smaller for concretes containing rounded aggregates or low cement-water ratios (by volume) and, in general, the rate of increase in workability tends to decrease with increasing air content. However, as a guide it may be assumed that every 1 per cent increase in air content will increase the compacting factor by 0.01 and reduce the V-B time by 10 per cent.AggregateFor given cement, water and aggregate contents, the workability of concrete is mainly influenced by the total surface area of the aggregate. The surface area is governed by the maximum size, grading and shape of the aggregate. Workability decreases as the specific surface increases, since this requires a greater proportion of cement paste to wet the aggregate particles, thus leaving a smaller amount of paste for lubrication. It follows that, all other conditions being equal, the workability will be increased when the maximum size of aggregate increases, the aggregate particles become rounded or the overall grading becomes coarser. However, the magnitude of this change inworkability depends on the mix proportions, the effect of the aggregate being negligible for very rich mixes (aggregate-cement ratios approaching 2). The practical significance of this is that for a given workability and cement-water ratio the amount of aggregate which can be used in a mix varies depending on the shape, maximum size and grading of the aggregate, as shown in figure 13.4 and tables 13.1 and 13.2. The influence of air-entrainment (4.5 per cent) on workability is shown also in figure 13.4.TABLE 13.1Effect of maximum size of aggregate of similar grading zone on aggregate-cement ratio of concrete having water-cement ratio of 0.55 by weight, based on McIntosh(1964)Maximum aggregatesize(mm)Aggregate-cement ratio (by weight)Low workability Medium workability High workability IrregulargravelCrushed rockIrregulargravelCrushed rockIrregulargravelCrushed rock9.5 19.0 37.5 5.36.27.64.85.56.44.75.46.54.24.75.54.44.95.93.74.45.2TABLE 13.2Effect of aggregate grading (maximum size 19.0 mm) on aggregate-cement ratio of concrete having medium workability and water-cement ratio of 0.55 by weight, basedon McIntosh (1964)Type of aggregateAggregate-cement ratioCoarse grading Fine gradingRounded gravel Irregular gravel Crushed rock 7.35.54.76.35.14.3Figure 13.4 Effect of aggregate shape on aggregate-cement ratio of concretes for different workabilities, based on Cornelius (1970)Several methods have been developed for evaluating the shape of aggregate, a subject discussed in chapter 12. Angularity factors together with grading modulus and equivalent mean diameter provide a means of considering the respective effects of shape, size and grading of aggregate (see chapter 15). Since the strength of a fully compacted concrete, for given materials and cement-water ratio, is not dependent on the ratio of coarse to fine aggregate, maximum economy can be obtained by using the coarse aggregate content producing the maximum workability for a given cement content (Hughes, 1960) (see figure 13.5). The use of optimum coarse aggregate content in concrete mix design is described in chapter 15. It should be noted that it is the volume fraction of an aggregate, rather than its weight, which is important.Figure 13.5 A typical relationship between workability and coarse aggregate content of concrete, based on Hughes (1960)The effect of surface texture on workability is shown in figure 13.6. It can be seen that aggregates with a smooth texture result in higher workabilities than aggregates with a rough texture. Absorption characteristics of aggregate also affect workability where dry or partially dry aggregates are used. In such a case workability drops, the extent of the reduction being dependent on the aggregate content and its absorption capacity.Ambient ConditionsEnvironmental factors that may cause a reduction in workability are temperature, humidity and wind velocityd. For a given concrete, changes in workability are governed by the rate of hydration of the cement and the rate of evaporation of water. Therefore both the time interval from the commencement of mixing to compaction and the conditions of exposure influence the reduction in workability. An increase in the temperature speeds up the rate at which water is used for hydration as well as its loss through evaporation. Likewise wind velocity and humidity influence the workability as they affect the rate of evaporation. It is worth remembering that in practice these factors depend on weather conditions and cannot be controlled.Figure 13.6 Effect of aggregate surface texture on aggregate-cement ratio of concretes for different workabilities, based on Cornelius (1970)TimeThe time that elapses between mixing of concrete and its final compaction depends on the general conditions of work such as the distance between the mixer and the point of placing, site procedures and general management. The associated reduction in workability is a direct result of loss of free water with time through evaporation, aggregate absorption and initial hydration of the cement. The rate of loss of workability is affected by certain characteristics of the constituent materials, for example, hydration and heat development characteristics of the cement, initial moisture content and porosity of the aggregate, as well as the ambient conditions.For a given concrete and set of ambient conditions, the rate of loss of workability with time depends on the conditions of handling. Where concrete remains undisturbed after mixing until it is placed, the loss of workability during the first hour can be substantial, the rate of loss of workability decreasing with time as illustrated by curve A in figure 13.7. On the other hand, if it is continuously agitated, as in the case of ready-mixed concrete, the loss of workability is reduced, particularly during the first hour or so (see curve B in figure 13.7). However,prolonged agitation during transportation may increase the fineness of the solidparticles through abrasion and produce a further reduction in workability. For concretes continuously agitated and undisturbed during transportation, the time intervals permitted (BS 1926) between the commencement of mixing and delivery on site are 2 hours and 1 hour respectively.For practical purposes, loss of workability assumes importance when concrete becomes so unworkable that it cannot be effectively compacted, with the result that its strength and other properties become adversely affected. Corrective measures frequently taken to ensure that concrete at the time of placing has the desired workability are either an initial increase in the water content or an increase in the water content with further mixing shortly before the concrete is discharged. When this results in a water content greater than that originally intended, some reduction in strength and durability of the hardened concrete is to be expected unless the cement content is increased accordingly. This important fact is frequently overlooked on site. It should be recalled that the loss of workability varies with the mix, the ambient conditions, the handling conditions and the delivery time. No restriction on delivery time is given in CP 110: Part 1 but the concrete must be capable of being placed and effectively compacted without the addition of further water. For detailed information on the use of ready-mixed concrete the reader is advised to consult the work of Dewar (1973).Figure 13.7 Loss of workability of concrete with time: (A) no agitation and (B)continuously agitated after mixing13.4 StabilityApart from being sufficiently workable, fresh concrete should have a composition such that its constituent materials remain uniformly distributed in the concrete during both the period between mixing and compaction and the period following compaction before the concrete stiffens. Because of differences in the particle size and specific gravities of the constituent materials there exists a natural tendency for them to separate. Concrete capable of maintaining the required uniformity is said to be stable and most cohesive mixes belong to this category. For an unstable mix the extent towhich the constituent materials will separate depends on the methods of transportation, placing and compaction. The two most common features of an unstable concrete are segregation and bleeding.SegregationWhen there is a significant tendency for the large and fine particles in a mix to become separated, segregation is said to have occurred. In general, the less cohesive the mix the greater the tendency for segregation to occur. Segregation is governed by the total specific surface of the solid particles including cement and the quantity of mortar in the mix. Harsh, extremely wet and dry mixes as well as those deficient in sand, particularly the finer particles, are prone to segregation. As far as possible, conditions conducive to segregation such as jolting of concrete during transportation, dropping from excessive heights during placing and over-vibration during compaction should be avoided.Blemishes, sand streaks, porous layers and honeycombing are a direct result of segregation. These features are not only unsightly but also adversely affect strength, durability and other properties of the hardened concrete. It is important to realize that the effects of segregation may not be indicated by the routine strength tests on control specimens since the conditions of placing and compaction of the specimens differ from those in the actual structure. There are no specific rules for suspecting possible segregation but after some experience of mixing and handling concrete it is not difficult to recognize mixes where this is likely to occur. For example, if a handful of concrete is squeezed in the hand and then released so that it lies in the palm, a cohesive concrete will be seen to retain its shape. A concrete which does not retain its shape under these conditions may well be prone to segregation and this is particularly so far wet mixes.BleedingDuring compaction and until the cement paste has hardened there is a natural tendency for the solid particles, depending on size and specific gravity, to exhibit a downward movement. Where the consistency of a mix is such that it is unable to hold all its water some of it is gradually displaced and rises to the surface, and some may also leak through the joints of the formwork. Separation of water from a mix in this manner is known as bleeding. While some of the water reaches the top surface some may become trapped under the larger particles and under the reinforcing bars. The resulting variations in the effective water content within a concrete massproduce corresponding changes in its properties. For example, the strength of the concrete immediately underneath the reinforcing bars and coarse aggregate particles may be much less than the average strength and the resistance to percolation of water in these areas is reduced. In general, the concrete strength tends to increase with depth below the top surface. The water which reaches the top surface presents the most serious practical problems. If it is not removed, the concrete at and near the top surface will be much weaker and less durable than the remainder of the concrete. This can be particularly troublesome in slabs which have a large surface area. On the other hand, removal of the surface water will unduly delay the finishing operation on the site.The risk of bleeding increases when concrete is compacted by vibration although this may be minimized by using a correctly designed mix and ensuring that the concrete is not over-vibrated. Rich mixes tend to bleed less than lean mixes. The type of cement employed is also important, the tendency for bleeding to occur decreasing as the fineness of the cement or its alkaline and tricalcium aluminate (C3A) content increases. Air-entrainment provides another very effective means of controlling bleeding in, for example, wet lean mixes where both segregation and bleeding are frequently troublesome.新拌混凝土的性能新拌混凝土为水、水泥、集料和外加剂（如果有的话）的混合物。
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。
土木工程钢筋混凝土结构中英文对照外文翻译文献
中英文翻译原文：DESIGN OF REINFORCED CONCRETESTRUCTURES1. BASIC CONCERPTS AND CHARACERACTERISTICS OF REINFORCED CONCRETEPlain concrete is formed from hardened mixture of cement, water , fine aggregate , coarse aggregate (crushed stone or gravel ) , air and often other admixtures . The plastic mix is placed and consolidated in the formwork, then cured to accelerate of the chemical hydration of hen cement mix and results in a hardened concrete. It is generally known that concrete has high compressive strength and low resistance to tension. Its tensile strength is approximatelyone-tenth of its compressive strength. Consequently, tensile reinforcement in the tension zone has to be provided to supplement the tensile strength of the reinforced concrete section.For example, a plain concrete beam under a uniformly distributed load q is shown in Fig .1.1(a), when the distributed load increases and reaches a value q=1.37KN/m , the tensile region at the mid-span will be cracked and the beam will fail suddenly . A reinforced concrete beam if the same size but has to steel reinforcing bars (2φ16) embedded at the bottom under a uniformly distributed load q is shown in Fig.1.1(b). The reinforcing bars take up the tension there after the concrete is cracked. When the load q is increased, the width of the cracks, the deflection and the stress of steel bars will increase . When the steel approaches the yielding stress ƒy , the deflection and the cracked width are so large offering some warning that the compression zone . The failure load q=9.31KN/m, is approximately 6.8 times that for the plain concrete beam.Concrete and reinforcement can work together because there is a sufficiently strong bond between the two materials, there are no relative movements of the bars and the surrounding concrete cracking. The thermal expansion coefficients of the two materials are 1.2×10-5K-1 for steel and 1.0×10-5~1.5×10-5K-1 for concrete .Generally speaking, reinforced structure possess following features :Durability .With the reinforcing steel protected by the concrete , reinforced concreteFig.1.1Plain concrete beam and reinforced concrete beamIs perhaps one of the most durable materials for construction .It does not rot rust , and is not vulnerable to efflorescence .(2)Fire resistance .Both concrete an steel are not inflammable materials .They would not be affected by fire below the temperature of 200℃ when there is a moderate amount of concrete cover giving sufficient thermal insulation to the embedded reinforcement bars.(3)High stiffness .Most reinforced concrete structures have comparatively large crosssections .As concrete has high modulus of elasticity, reinforced concrete structures are usually stiffer than structures of other materials, thus they are less prone to large deformations, This property also makes the reinforced concrete less adaptable to situations requiring certainflexibility, such as high-rise buildings under seismic load, and particular provisions have to be made if reinforced concrete is used.(4)Locally available resources. It is always possible to make use of the local resources of labour and materials such as fine and coarse aggregates. Only cement and reinforcement need to be brought in from outside provinces.(5)Cost effective. Comparing with steel structures, reinforced concrete structures arecheaper. 1.37kn/m6m 200 400(a)plain concrete beam 9.31kn/m6m 200 400(b)Reinfoced concrete beam2φ16(6)Large dead mass, The density of reinforced concrete may reach2400~2500kg/pare with structures of other materials, reinforced concrete structures generally have a heavy dead mass. However, this may be not always disadvantageous, particularly for those structures which rely on heavy dead weight to maintain stability, such as gravity dam and other retaining structure. The development and use of light weight aggregate have to a certain extent make concrete structure lighter.(7)Long curing period.. It normally takes a curing period of 28 day under specified conditions for concrete to acquire its full nominal strength. This makes the progress of reinforced concrete structure construction subject to seasonal climate. The development of factory prefabricated members and investment in metal formwork also reduce the consumption of timber formwork materials.(8)Easily cracked. Concrete is weak in tension and is easily cracked in the tension zone. Reinforcing bars are provided not to prevent the concrete from cracking but to take up the tensile force. So most of the reinforced concrete structure in service is behaving in a cracked state. This is an inherent is subjected to a compressive force before working load is applied. Thus the compressed concrete can take up some tension from the load.2. HISTOEICAL DEVELPPMENT OF CONCRETE STRUCTUREAlthough concrete and its cementitious(volcanic) constituents, such as pozzolanic ash, have been used since the days of Greek, the Romans, and possibly earlier ancient civilization, the use of reinforced concrete for construction purpose is a relatively recent event, In 1801, F. Concrete published his statement of principles of construction, recognizing the weakness if concrete in tension, The beginning of reinforced concrete is generally attributed to Frenchman J. L. Lambot, who in 1850 constructed, for the first time, a small boat with concrete for exhibition in the 1855 World’s Fair in Paris. In England, W. B. Wilkinson registered a patent for reinforced concrete l=floor slab in 1854.J.Monier, a French gardener used metal frames as reinforcement to make garden plant containers in 1867. Before 1870, Monier had taken a series of patents to make reinforced concrete pipes, slabs, and arches. But Monier had no knowledge of the working principle of this new material, he placed the reinforcement at the mid-depth of his wares. Then little construction was done in reinforced concrete. It is until 1887, when the German engineers Wayss and Bauschinger proposed to place the reinforcement in the tension zone, the use of reinforced concrete as a material of construction began to spread rapidly. In1906, C. A. P. Turner developed the first flat slab without beams.Before the early twenties of 20th century, reinforced concrete went through the initial stage of its development, Considerable progress occurred in the field such that by 1910 the German Committee for Reinforced Concrete, the Austrian Concrete Committee, the American Concrete Institute, and the British Concrete Institute were established. Various structural elements, such as beams, slabs, columns, frames, arches, footings, etc. were developed using this material. However, the strength of concrete and that of reinforcing bars were still very low. The common strength of concrete at the beginning of 20th century was about 15MPa in compression, and the tensile strength of steel bars was about 200MPa. The elements were designed along the allowable stresses which was an extension of the principles in strength of materials.By the late twenties, reinforced concrete entered a new stage of development. Many buildings, bridges, liquid containers, thin shells and prefabricated members of reinforced concrete were concrete were constructed by 1920. The era of linear and circular prestressing began.. Reinforced concrete, because of its low cost and easy availability, has become the staple material of construction all over the world. Up to now, the quality of concrete has been greatly improved and the range of its utility has been expanded. The design approach has also been innovative to giving the new role for reinforced concrete is to play in the world of construction.The concrete commonly used today has a compressive strength of 20~40MPa. For concrete used in pre-stressed concrete the compressive strength may be as high as 60~80MPa. The reinforcing bars commonly used today has a tensile strength of 400MPa, and the ultimate tensile strength of prestressing wire may reach 1570~1860Pa. The development of high strength concrete makes it possible for reinforced concrete to be used in high-rise buildings, off-shore structures, pressure vessels, etc. In order to reduce the dead weight of concrete structures, various kinds of light concrete have been developed with a density of 1400~1800kg/m3. With a compressive strength of 50MPa, light weight concrete may be used in load bearing structures. One of the best examples is the gymnasium of the University of Illinois which has a span of 122m and is constructed of concrete with a density of 1700kg/m3. Another example is the two 20-story apartment houses at the Xi-Bian-Men in Beijing. The walls of these two buildings are light weight concrete with a density of 1800kg/m3.The tallest reinforced concrete building in the world today is the 76-story Water Tower Building in Chicago with a height of 262m. The tallest reinforced concrete building in China today is the 63-story International Trade Center in GuangZhou with a height a height of 200m. The tallest reinforced concrete construction in the world is the 549m high International Television Tower in Toronto, Canada. He prestressedconcrete T-section simply supported beam bridge over the Yellow River in Luoyang has 67 spans and the standard span length is 50m.In the design of reinforced concrete structures, limit state design concept has replaced the old allowable stresses principle. Reliability analysis based on the probability theory has very recently been introduced putting the limit state design on a sound theoretical foundation. Elastic-plastic analysis of continuous beams is established and is accepted in most of the design codes. Finite element analysis is extensively used in the design of reinforced concrete structures and non-linear behavior of concrete is taken into consideration. Recent earthquake disasters prompted the research in the seismic resistant reinforced of concrete structures. Significant results have been accumulated.3. SPECIAL FEATURES OF THE COURSEReinforced concrete is a widely used material for construction. Hence, graduates of every civil engineering program must have, as a minimum requirement, a basic understanding of the fundamentals of reinforced concrete.The course of Reinforced Concrete Design requires the prerequisite of Engineering Mechanics, Strength of Materials, and some if not all, of Theory of Structures, In all these courses, with the exception of Strength of Materials to some extent, a structure is treated of in the abstract. For instance, in the theory of rigid frame analysis, all members have an abstract EI/l value, regardless of what the act value may be. But the theory of reinforced concrete is different, it deals with specific materials, concrete and steel. The values of most parameters must be determined by experiments and can no more be regarded as some abstract. Additionally, due to the low tensile strength of concrete, the reinforced concrete members usually work with cracks, some of the parameters such as the elastic modulus I of concrete and the inertia I of section are variable with the loads.The theory of reinforced concrete is relatively young. Although great progress has been made, the theory is still empirical in nature in stead of rational. Many formulas can not be derived from a few propositions, and may cause some difficulties for students. Besides, due to the difference in practice in different countries, most countries base their design methods on their own experience and experimental results. Consequently, what one learns in one country may be different in another country. Besides, the theory is still in a stage of rapid development and is subjected to revision according to new findings from research. In China, the design code undergoes major revision in about every fifteen years and with minor revision in between. This book is based on the latest current code in China “Code for Design of Concrete Structures”(GB50010-2002). The studentsmust keep in mind that this course can not give them the knowledge which is universally valid regardless of time and place, but the basic principles on which the current design method in the country is established.The desk calculator has made calculations to a high degree of precision possible and easy. Students must not forget that concrete is a man-made material and a 10% consistency in quality is remarkably good. Reinforcing bad=rs are rolled in factory, yet variation is=n strength may be as high as 5%. Besides, the position of bars in the formwork may deviate from their design positions. In fact two figure accuracy is adequate for almost all the cases, rather than carrying the calculations to meaningless precision. The time and effort of the designer are better spent to find out where the tension may occur to resist it by placing reinforcement there.中文译文：钢筋混凝土结构设计一、钢筋混凝土基本概念和特点混凝土是指由水泥胶凝的水、细致聚合体、粗聚合物（碎石或沙砾）、空气、以及其他混合物的坚硬混合物。
沥青混凝土中英文对照外文翻译文献
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)中英文对照翻译Asphalt Mixtures-Applications, Theory andPrinciples1 . ApplicationsAsphalt materials find wide usage in the construction industry. The use of asphalt as a cementing agent in pavements is the most common of its applications, however,and the one that will be considered here.Asphalt products are used to produce flexible pavements for highways andairports. The term “flexible” is used to distinguish these pavements from those made with Portland cement, which are classified as rigid pavements, that is, having beam strength. This distinction is important because it provides they key to the design approach which must be used for successful flexible pavement structures.The flexible pavement classification may be further broken down into high andlow types, the type usually depending on whether a solid or liquid asphalt product is used. The low types of pavement are made with the cutback, or emulsion, liquid products and are very widely used throughout this country. Descriptive terminology附 录has been developed in various sections of the country to the extent that one pavement type may have several names. However, the general process followed in constructionis similar for most low-type pavements and can be described as one in which the aggregate and the asphalt product are usually applied to the roadbed separately and there mixed or allowed to mix, forming the pavement.The high type of asphalt pavements is made with asphalt cements of some selected penetration grade.中英文对照外文翻译文献中英文对照外文翻译文献Fig. ·1 A modern asphalt concrete highway. Shoulder striping is used as a safely feature.Fig. ·2 Asphalt concrete at the San Francisco International Airport.They are used when high wheel loads and high volumes of traffic occur and are, therefore, often designed for a particular installation.2 . Theory of asphalt concrete mix designHigh types of flexible pavement are constructed by combining an asphalt cement, often in the penetration grade of 85 to 100, with aggregates that are usually divided into three groups, based on size. The three groups are coarse aggregates, fineaggregates, and mineral filler. These will be discussed in detail in later chapter.Each of the constituent parts mentioned has a particular function in the asphaltmixture, and mix proportioning or design is the process of ensuring that no function is neglected. Before these individual functions are examined, however, the criteria for pavement success and failure should be considered so that design objectives can be established.A successful flexible pavement must have several particular properties. First, itmust be stable, that is to resistant to permanent displacement under load. Deformation of an asphalt pavement can occur in three ways, two unsatisfactory and one desirable.附 录Plastic deformation of a pavement failure and which is to be avoided if possible. Compressive deformation of the pavement results in a dimensional change in the pavement, and with this change come a loss of resiliency and usually a degree of roughness. This deformation is less serious than the one just described, but it, too, leads to pavement failure. The desirable type of deformation is an elastic one, which actually is beneficial to flexible pavements and is necessary to their long life.The pavement should be durable and should offer protection to the subgrade. Asphalt cement is not impervious to the effects of weathering, and so the design must minimize weather susceptibility. A durable pavement that does not crack or ravel will probably also protect the roadbed. It must be remembered that flexible pavements transmit loads to the subgrade without significant bridging action, and so a dry firm base is absolutely essential.Rapidly moving vehicles depend on the tire-pavement friction factor for control and safety. The texture of the pavement surfaces must be such that an adequate skid resistance is developed or unsafe conditions result. The design procedure should be used to select the asphalt material and aggregates combination which provides a skid resistant roadway.Design procedures which yield paving mixtures embodying all these properties are not available. Sound pavements are constructed where materials and methods are selected by using time-tested tests and specifications and engineering judgments along with a so-called design method.The final requirement for any pavement is one of economy. Economy, again, cannot be measured directly, since true economy only begins with construction cost and is not fully determinable until the full useful life of the pavement has been recorded. If, however, the requirements for a stable, durable, and safe pavement are met with a reasonable safety factor, then the best interests of economy have probably been served as well.With these requirements in mind, the functions of the constituent parts can be examined with consideration give to how each part contributes to now-established objectives or requirements. The functions of the aggregates is to carry the load imposed on the pavement, and this is accomplished by frictional resistance and interlocking between the individual pieces of aggregates. The carrying capacity of the asphalt pavement is, then, related to the surface texture (particularly that of the fine aggregate) and the density, or “compactness,”, of the aggregates. Surfa ce texture中英文对照外文翻译文献中英文对照外文翻译文献varies with different aggregates, and while a rough surface texture is desired, this may not be available in some localities. Dense mixtures are obtained by using aggregates that are either naturally or artificially “well graded”. This means tha that are either naturally or artificially “well graded”. This means that the fine t the fineaggregate serves to fill the voids in the coarser aggregates. In addition to affecting density and therefore strength characteristics, the grading also influences workability. When an excess of coarse aggregate is used, the mix becomes harsh and hard to work. When an excess of mineral filler is used, the mixes become gummy and difficult to manage.The asphalt cement in the flexible pavement is used to bind the aggregateparticles together and to waterproof the pavements. Obtaining the proper asphalt content is extremely important and bears a significant influence on all the items marking a successful pavement. A chief objective of all the design methods which have been developed is to arrive at the best asphalt content for a particularcombination of aggregates.3 . Mix design principlesCertain fundamental principles underlie the design procedures that have beendeveloped. Before these procedures can be properly studied or applied, someconsideration of these principles is necessary.Asphalt pavements are composed of aggregates, asphalt cement, and voids.Considering the aggregate alone, all the space between particles is void space. The volume of aggregate voids depends on grading and can vary widely. When the asphalt cement is added, a portion of these aggregate voids is filled and a final air-voidvolume is retained. The retention of this air-void volume is very important to thecharacteristics of the mixture. The term air-void volume is used, since these voids are weightless and are usually expressed as a percentage of the total volume of thecompacted mixture.An asphalt pavement carries the applied load by particle friction and interlock. If the particles are pushed apart for any reason , then the pavement stability is destroyed. This factor indicates that certainly no more asphalt should be added than the aggregate voids can readily hold. However ,asphalt cement is susceptible to volume change and the pavement is subject to further compaction under use. If the pavement has no air voids when placed, or if it loses them under traffic, then the expanding asphalt will overflow in a condition known as bleeding. The loss of asphalt cement throughbleeding weakens the pavement and also reduces surface friction, making the roadway附 录hazardous.Fig. ·3 Cross section of an asphalt concrete pavement showing the aggregate framework bound together by asphalt cement.The need for a minimum air-void volume (usually 2 or 3 per cent ) has been established. In addition, a maximum air-void volume of 5 to 7 per cent should not be exceed. An excess of air voids promotes raveling of the pavement and also permits water to enter and speed up the deteriorating processes. Also, in the presence of excess air the asphalt cement hardens and ages with an accompanying loss of durability and resiliency.The air-void volume of the mix is determined by the degree of compaction as well as by the asphalt content. For a given asphalt content, a lightly compacted mix will have a large voids volume and a lower density and a greater strength will result. In the laboratory, the compaction is controlled by using a specified hammer and regulating the number of blows and the energy per blow. In the field, the compaction and the air voids are more difficult to control and tests must be made no specimens taken from the compacted pavement to cheek on the degree of compaction being obtained. Traffic further compact the pavement, and allowance must be made for this in the design. A systematic checking of the pavement over an extended period is needed to given factual information for a particular mix. A change in density of several per cent is not unusual, however.Asphalt content has been discussed in connection with various facets of the ix design problem. It is a very important factor in the mix design and has a bearing an all the characteristics ld a successful pavement: stability, skid resistance, durability, and economy. As has been mentioned, the various design procedures are intended to provide a means for selecting the asphalt content . These tests will be considered in中英文对照外文翻译文献中英文对照外文翻译文献detail in a future chapter ,but the relationship between asphalt content and the measurable properties of stability, unit weight, and air voids will be discussed here.Fig.4 Variations in stability, unit weight, and air-void content with asphalt cement content.If the gradation and type of aggregate, the degree of compaction, and the type of asphalt cement are controlled, then the strength varies in a predictable manner. The strength will increase up to some optimum asphalt content and then decrease with further additions. The pattern of strength variation will be different when the other mix factors are changed, and so only a typical pattern can be predicted prior to actual testing.Unit weight varies in the same manner as strength when all other variable arecontrolled. It will reach some peak value at an asphalt content near that determined from the strength curve and then fall off with further additions.As already mentioned, the air-void volume will vary with asphalt content. However, the manner of variation is different in that increased asphalt content willdecrease air-void volume to some minimum value which is approached asymptotically. With still greater additions of asphalt material the particles of aggregate are only pushed apart and no change occurs in air-void volume. In summary, certain principles involving aggregate gradation, air-void volume, asphalt content, and compaction mist be understood before proceeding to actual mix design. The proper design based on these principles will result in sound pavements. If these principles are overlooked, the pavement may fail by one or more of therecognized modes of failure: shoving, rutting, corrugating, becoming slick when the max is too …rich‟; raveling, cracking,having low durability when the mix is too …lean‟.It should be again emphasized that the strength of flexible is, more accurately, a附 录stability and does not indicate any ability to bridge weak points in the subgrade by beam strength. No asphalt mixture can be successful unless it rests on top of a properly designed and constructed base structure. This fact, that the surface is no better than the base, must be continually in the minds of those concerned with any aspect of flexible pavement work.中英文对照外文翻译文献中英文对照外文翻译文献译文：译文：沥青混合料的应用、理论和原则1、应用沥青材料如今在建筑行业广泛使用。
钢筋混凝土中英文对照外文翻译文献
中英文资料对照外文翻译目录1 中文翻译 (1)1.1钢筋混凝土 (1)1.2土方工程 (2)1.3结构的安全度 (3)2 外文翻译 (6)2.1 Reinforced Concrete (6)2.2 Earthwork (7)2.3 Safety of Structures (9)1 中文翻译1.1钢筋混凝土素混凝土是由水泥、水、细骨料、粗骨料（碎石或；卵石）、空气，通常还有其他外加剂等经过凝固硬化而成。
将可塑的混凝土拌合物注入到模板内，并将其捣实，然后进行养护，以加速水泥与水的水化反应，最后获得硬化的混凝土。
其最终制成品具有较高的抗压强度和较低的抗拉强度。
其抗拉强度约为抗压强度的十分之一。
因此，截面的受拉区必须配置抗拉钢筋和抗剪钢筋以增加钢筋混凝土构件中较弱的受拉区的强度。
由于钢筋混凝土截面在均质性上与标准的木材或钢的截面存在着差异，因此，需要对结构设计的基本原理进行修改。
将钢筋混凝土这种非均质截面的两种组成部分按一定比例适当布置，可以最好的利用这两种材料。
这一要求是可以达到的。
因混凝土由配料搅拌成湿拌合物，经过振捣并凝固硬化，可以做成任何一种需要的形状。
如果拌制混凝土的各种材料配合比恰当，则混凝土制成品的强度较高，经久耐用，配置钢筋后，可以作为任何结构体系的主要构件。
浇筑混凝土所需要的技术取决于即将浇筑的构件类型，诸如：柱、梁、墙、板、基础，大体积混凝土水坝或者继续延长已浇筑完毕并且已经凝固的混凝土等。
对于梁、柱、墙等构件，当模板清理干净后应该在其上涂油，钢筋表面的锈及其他有害物质也应该被清除干净。
浇筑基础前，应将坑底土夯实并用水浸湿6英寸，以免土壤从新浇的混凝土中吸收水分。
一般情况下，除使用混凝土泵浇筑外，混凝土都应在水平方向分层浇筑，并使用插入式或表面式高频电动振捣器捣实。
必须记住，过分的振捣将导致骨料离析和混凝土泌浆等现象，因而是有害的。
水泥的水化作用发生在有水分存在，而且气温在50°F以上的条件下。
水泥和混凝土的制作流程英文作文
水泥和混凝土的制作流程英文作文The Production Process of Cement and ConcreteCement and concrete are two essential building materials that are widely used in construction projects around the world. Cement is the key ingredient in concrete, acting as the binding agent that holds the mixture together. In this article, we will explore the production process of cement and concrete, from raw materials to the final product.1. Cement Production ProcessThe production of cement begins with the extraction of raw materials from quarries. The main ingredients used in cement production are limestone, clay, and gypsum. These raw materials are crushed and ground into a fine powder, which is then heated in a kiln at high temperatures. This process, known as clinkering, causes the raw materials to react chemically and form small nodules called clinker.The clinker is then mixed with a small amount of gypsum to regulate the setting time of the cement. The final product, known as Portland cement, is finely ground into a powder and packaged for distribution. Portland cement is the most common type of cement used in construction due to its versatility and strength.2. Concrete Production ProcessConcrete is made by mixing cement with aggregates, such as sand and gravel, and water. The proportions of these ingredients can vary depending on the desired strength and consistency of the concrete mix. The process of making concrete involves several steps:- Batching: The ingredients are measured and mixed in precise proportions in a concrete batching plant.- Mixing: The ingredients are mixed together in a concrete mixer to form a uniform mixture.- Transporting: The mixed concrete is transported to the construction site using trucks equipped with rotating drums to keep the concrete in a liquid state.- Pouring: The concrete is poured into molds or formwork at the construction site and allowed to set and harden.Once the concrete has cured, it gains strength and becomes a durable building material suitable for a wide range of applications, from foundations and walls to roads and bridges.3. Quality Control and TestingQuality control is an essential part of the cement and concrete production process to ensure that the materials meet industry standards and specifications. Samples of cement and concrete are tested for properties such as compressive strength, workability, and durability. These tests help engineers and construction professionals ensure that the materials will perform as expected in the intended application.In conclusion, the production of cement and concrete involves a series of steps from raw material extraction to the final product. Both materials play a crucial role in the construction industry, providing the foundation for modern infrastructure and buildings. By understanding the production process of cement and concrete, we can appreciate the complexity and importance of these essential building materials.。
混凝土结构配筋设计中英文对照外文翻译文献
(文档含英文原文和中文翻译)中英文对照外文翻译英文原文：Concrete structure reinforcement designAbstract：structure in the long-term natural environment and under the use environment's function, its function is weaken inevitably gradually, our structural engineering's duty not just must finish the building earlier period the project work, but must be able the science appraisal structure damage objective law and the degree, and adopts the effective method guarantee structure the security use, that the structure reinforcement will become an important work. What may foresee will be the 21st century, the human building also by the concrete structure, the steel structure, the bricking-up structure and so on primarily, the present stage I will think us in the structure reinforcement this aspect research should also take this as themain breakthrough direction.Key word： Concrete structure reinforcement bricking-up structure reinforcement steel structure reinforcement1 Concrete structure reinforcementConcrete structure's reinforcement divides into the direct reinforcement and reinforces two kinds indirectly, when the design may act according to the actual condition and the operation requirements choice being suitable method and the necessary technology.1.1the direct reinforcement's general method1）Enlarges the section reinforcement lawAdds the concretes cast-in-place level in the reinforced concrete member in bending compression zone, may increase the section effective height, the expansion cross sectional area, thus enhances the component right section anti-curved, the oblique section anti-cuts ability and the section rigidity, plays the reinforcement reinforcement the role.In the suitable muscle scope, the concretes change curved the component right section supporting capacity increase along with the area of reinforcement and the intensity enhance. In the original component right section ratio of reinforcement nottoo high situation, increases the main reinforcement area to be possible to propose the plateau component right section anti-curved supporting capacity effectively. Is pulledin the section the area to add the cast-in-place concrete jacket to increase the component section, through new Canada partial and original component joint work,but enhances the component supporting capacity effectively, improvement normal operational performance.Enlarges the section reinforcement law construction craft simply, compatible,and has the mature design and the construction experience; Is suitable in Liang, the board, the column, the wall and the general structure concretes reinforcement; But scene construction's wet operating time is long, to produces has certain influence withthe life, and after reinforcing the building clearance has certain reduction.2) Replacement concretes reinforcement lawThis law's merit with enlarges the method of sections to be close, and afterreinforcing, does not affect building's clearance, but similar existence construction wet operating time long shortcoming; Is suitable somewhat low or has concretes carrier's and so on serious defect Liang, column in the compression zone concretes intensity reinforcement.3) the caking outsourcing section reinforcement lawOutside the Baotou Steel Factory reinforcement is wraps in the section or the steel plate is reinforced component's outside, outside the Baotou Steel Factory reinforces reinforced concrete Liang to use the wet outsourcing law generally, namely uses the epoxy resinification to be in the milk and so on methods with to reinforce the section the construction commission to cake a whole, after the reinforcement component, because is pulled with the compressed steel cross sectional area large scale enhancement, therefore right section supporting capacity and section rigidity large scale enhancement.This law also said that the wet outside Baotou Steel Factory reinforcement law, the stress is reliable, the construction is simple, the scene work load is small, but is big with the steel quantity, and uses in above not suitably 600C in the non-protection's situation the high temperature place; Is suitable does not allow in the use obviously to increase the original component section size, but requests to sharpen its bearing capacity large scale the concrete structure reinforcement.4) Sticks the steel reinforcement lawOutside the reinforced concrete member in bending sticks the steel reinforcement is (right section is pulled in the component supporting capacity insufficient sector area, right section compression zone or oblique section) the superficial glue steel plate, like this may enhance is reinforced component's supporting capacity, and constructs conveniently.This law construction is fast, the scene not wet work or only has the plastering and so on few wet works, to produces is small with the life influence, and after reinforcing, is not remarkable to the original structure outward appearance and the original clearance affects, but the reinforcement effect is decided to a great extent by the gummy craft and the operational level; Is suitable in the withstanding static function, and is in the normal humidity environment to bend or the tension memberreinforcement.5) Glue fibre reinforcement plastic reinforcement lawOutside pastes the textile fiber reinforcement is pastes with the cementing material the fibre reinforcement compound materials in is reinforced the component to pull the region, causes it with to reinforce the section joint work, achieves sharpens the component bearing capacity the goal. Besides has glues the steel plate similar merit, but also has anticorrosive muddy, bears moistly, does not increase the self-weight of structure nearly, durably, the maintenance cost low status merit, but needs special fire protection processing, is suitable in each kind of stress nature concrete structure component and the general construction.This law's good and bad points with enlarge the method of sections to be close; Is suitable reinforcement which is insufficient in the concrete structure component oblique section supporting capacity, or must exert the crosswise binding force to the compressional member the situation.6) Reeling lawThis law's good and bad points with enlarge the method of sections to be close; Is suitable reinforcement which is insufficient in the concrete structure component oblique section supporting capacity, or must exert the crosswise binding force to the compressional member the situation.7) Fang bolt anchor lawThis law is suitable in the concretes intensity rank is the C20~C60 concretes load-bearing member transformation, the reinforcement; It is not suitable for already the above structure which and the light quality structure makes decent seriously.1.2The indirect reinforcement's general method1)Pre-stressed reinforcement law(1)Thepre-stressed horizontal tension bar reinforces concretes member in bending,because the pre-stressed and increases the exterior load the combined action, in the tension bar has the axial tension, this strength eccentric transmits on the component through the pole end anchor (, when tension bar and Liang board bottom surface close fitting, tension bar can look for tune together with component, thisfashion has partial pressures to transmit directly for component bottom surface), has the eccentric compression function in the component, this function has overcome the bending moment which outside the part the load produces, reduced outside the load effect, thus sharpened component's anti-curved ability. At the same time, because the tension bar passes to component's pressure function, the component crack development can alleviate, the control, the oblique section anti-to cut the supporting capacity also along with it enhancement.As a result of the horizontal lifting stem's function, the original component's section stress characteristic by received bends turned the eccentric compression, therefore, after the reinforcement, component's supporting capacity was mainly decided in bends under the condition the original component's supporting capacity 。
钢筋混凝土结构中英文对照外文翻译文献
中英文对照外文翻译(文档含英文原文和中文翻译)Reinforced ConcreteConcrete and reinforced concrete are used as building materials in every country. In many, including the United States and Canada, reinforced concrete is a dominant structural material in engineered construction. The universal nature of reinforced concrete construction stems from the wide availability of reinforcing bars and the constituents of concrete, gravel, sand, and cement, the relatively simple skills required in concrete construction, and the economy of reinforced concrete compared to other forms of construction. Concrete and reinforced concrete are used in bridges, buildings of all sorts underground structures, water tanks, television towers, offshore oil exploration and production structures, dams, and even in ships.Reinforced concrete structures may be cast-in-place concrete, constructed in their final location, or they may be precast concreteproduced in a factory and erected at the construction site. Concrete structures may be severe and functional in design, or the shape and layout and be whimsical and artistic. Few other building materials off the architect and engineer such versatility and scope.Concrete is strong in compression but weak in tension. As a result, cracks develop whenever loads, or restrained shrinkage of temperature changes, give rise to tensile stresses in excess of the tensile strength of the concrete. In a plain concrete beam, the moments about the neutral axis due to applied loads are resisted by an internal tension-compression couple involving tension in the concrete. Such a beam fails very suddenly and completely when the first crack forms. In a reinforced concrete beam, steel bars are embedded in the concrete in such a way that the tension forces needed for moment equilibrium after the concrete cracks can be developed in the bars.The construction of a reinforced concrete member involves building a from of mold in the shape of the member being built. The form must be strong enough to support both the weight and hydrostatic pressure of the wet concrete, and any forces applied to it by workers, concrete buggies, wind, and so on. The reinforcement is placed in this form and held in place during the concreting operation. After the concrete has hardened, the forms are removed. As the forms are removed, props of shores are installed to support the weight of the concrete until it has reached sufficient strength to support the loads by itself.The designer must proportion a concrete member for adequate strength to resist the loads and adequate stiffness to prevent excessive deflections. In beam must be proportioned so that it can be constructed. For example, the reinforcement must be detailed so that it can be assembled in the field, and since the concrete is placed in the form after the reinforcement is in place, the concrete must be able to flow around, between, and past the reinforcement to fill all parts of the form completely.The choice of whether a structure should be built of concrete, steel, masonry, or timber depends on the availability of materials and on a number of value decisions. The choice of structural system is made by the architect of engineer early in the design, based on the following considerations:1. Economy. Frequently, the foremost consideration is the overall const of the structure. This is, of course, a function of the costs of the materials and the labor necessary to erect them. Frequently, however, the overall cost is affected as much or more by the overall construction time since the contractor and owner must borrow or otherwise allocate money to carry out the construction and will not receive a return on this investment until the building is ready for occupancy. In a typical large apartment of commercial project, the cost of construction financing will be a significant fraction of the total cost. As a result, financial savings due to rapid construction may more than offset increased material costs. For this reason, any measures the designer can take to standardize the design and forming will generally pay off in reduced overall costs.In many cases the long-term economy of the structure may be more important than the first cost. As a result, maintenance and durability are important consideration.2. Suitability of material for architectural and structural function.A reinforced concrete system frequently allows the designer to combine the architectural and structural functions. Concrete has the advantage that it is placed in a plastic condition and is given the desired shape and texture by means of the forms and the finishing techniques. This allows such elements ad flat plates or other types of slabs to serve as load-bearing elements while providing the finished floor and / or ceiling surfaces. Similarly, reinforced concrete walls can provide architecturally attractive surfaces in addition to having the ability to resist gravity, wind, or seismic loads. Finally, the choice of size of shape is governed by the designer and not by the availability of standard manufactured members.3. Fire resistance. The structure in a building must withstand the effects of a fire and remain standing while the building is evacuated and the fire is extinguished. A concrete building inherently has a 1- to 3-hour fire rating without special fireproofing or other details. Structural steel or timber buildings must be fireproofed to attain similar fire ratings.4. Low maintenance.Concrete members inherently require less maintenance than do structural steel or timber members. This is particularly true if dense, air-entrained concrete has been used forsurfaces exposed to the atmosphere, and if care has been taken in the design to provide adequate drainage off and away from the structure. Special precautions must be taken for concrete exposed to salts such as deicing chemicals.5. Availability of materials. Sand, gravel, cement, and concrete mixing facilities are very widely available, and reinforcing steel can be transported to most job sites more easily than can structural steel. As a result, reinforced concrete is frequently used in remote areas.On the other hand, there are a number of factors that may cause one to select a material other than reinforced concrete. These include:1. Low tensile strength.The tensile strength concrete is much lower than its compressive strength ( about 1/10 ), and hence concrete is subject to cracking. In structural uses this is overcome by using reinforcement to carry tensile forces and limit crack widths to within acceptable values. Unless care is taken in design and construction, however, these cracks may be unsightly or may allow penetration of water. When this occurs, water or chemicals such as road deicing salts may cause deterioration or staining of the concrete. Special design details are required in such cases. In the case of water-retaining structures, special details and / of prestressing are required to prevent leakage.2. Forms and shoring. The construction of a cast-in-place structure involves three steps not encountered in the construction of steel or timber structures. These are ( a ) the construction of the forms, ( b ) the removal of these forms, and (c) propping or shoring the new concrete to support its weight until its strength is adequate. Each of these steps involves labor and / or materials, which are not necessary with other forms of construction.3. Relatively low strength per unit of weight for volume.The compressive strength of concrete is roughly 5 to 10% that of steel, while its unit density is roughly 30% that of steel. As a result, a concrete structure requires a larger volume and a greater weight of material than does a comparable steel structure. As a result, long-span structures are often built from steel.4. Time-dependent volume changes. Both concrete and steel undergo-approximately the same amount of thermal expansion and contraction. Because there is less mass of steel to be heated or cooled,and because steel is a better concrete, a steel structure is generally affected by temperature changes to a greater extent than is a concrete structure. On the other hand, concrete undergoes frying shrinkage, which, if restrained, may cause deflections or cracking. Furthermore, deflections will tend to increase with time, possibly doubling, due to creep of the concrete under sustained loads.In almost every branch of civil engineering and architecture extensive use is made of reinforced concrete for structures and foundations. Engineers and architects requires basic knowledge of reinforced concrete design throughout their professional careers. Much of this text is directly concerned with the behavior and proportioning of components that make up typical reinforced concrete structures-beams, columns, and slabs. Once the behavior of these individual elements is understood, the designer will have the background to analyze and design a wide range of complex structures, such as foundations, buildings, and bridges, composed of these elements.Since reinforced concrete is a no homogeneous material that creeps, shrinks, and cracks, its stresses cannot be accurately predicted by the traditional equations derived in a course in strength of materials for homogeneous elastic materials. Much of reinforced concrete design in therefore empirical, i.e., design equations and design methods are based on experimental and time-proved results instead of being derived exclusively from theoretical formulations.A thorough understanding of the behavior of reinforced concrete will allow the designer to convert an otherwise brittle material into tough ductile structural elements and thereby take advantage of concrete’s desirable characteristics, its high compressive strength, its fire resistance, and its durability.Concrete, a stone like material, is made by mixing cement, water, fine aggregate ( often sand ), coarse aggregate, and frequently other additives ( that modify properties ) into a workable mixture. In its unhardened or plastic state, concrete can be placed in forms to produce a large variety of structural elements. Although the hardened concrete by itself, i.e., without any reinforcement, is strong in compression, it lacks tensile strength and therefore cracks easily. Because unreinforced concrete is brittle, it cannot undergo large deformations under load and failssuddenly-without warning. The addition fo steel reinforcement to the concrete reduces the negative effects of its two principal inherent weaknesses, its susceptibility to cracking and its brittleness. When the reinforcement is strongly bonded to the concrete, a strong, stiff, and ductile construction material is produced. This material, called reinforced concrete, is used extensively to construct foundations, structural frames, storage takes, shell roofs, highways, walls, dams, canals, and innumerable other structures and building products. Two other characteristics of concrete that are present even when concrete is reinforced are shrinkage and creep, but the negative effects of these properties can be mitigated by careful design.A code is a set technical specifications and standards that control important details of design and construction. The purpose of codes it produce structures so that the public will be protected from poor of inadequate and construction.Two types f coeds exist. One type, called a structural code, is originated and controlled by specialists who are concerned with the proper use of a specific material or who are involved with the safe design of a particular class of structures.The second type of code, called a building code, is established to cover construction in a given region, often a city or a state. The objective of a building code is also to protect the public by accounting for the influence of the local environmental conditions on construction. For example, local authorities may specify additional provisions to account for such regional conditions as earthquake, heavy snow, or tornados. National structural codes genrally are incorporated into local building codes.The American Concrete Institute ( ACI ) Building Code covering the design of reinforced concrete buildings. It contains provisions covering all aspects of reinforced concrete manufacture, design, and construction. It includes specifications on quality of materials, details on mixing and placing concrete, design assumptions for the analysis of continuous structures, and equations for proportioning members for design forces.All structures must be proportioned so they will not fail or deform excessively under any possible condition of service. Therefore it is important that an engineer use great care in anticipating all the probableloads to which a structure will be subjected during its lifetime.Although the design of most members is controlled typically by dead and live load acting simultaneously, consideration must also be given to the forces produced by wind, impact, shrinkage, temperature change, creep and support settlements, earthquake, and so forth.The load associated with the weight of the structure itself and its permanent components is called the dead load. The dead load of concrete members, which is substantial, should never be neglected in design computations. The exact magnitude of the dead load is not known accurately until members have been sized. Since some figure for the dead load must be used in computations to size the members, its magnitude must be estimated at first. After a structure has been analyzed, the members sized, and architectural details completed, the dead load can be computed more accurately. If the computed dead load is approximately equal to the initial estimate of its value ( or slightly less ), the design is complete, but if a significant difference exists between the computed and estimated values of dead weight, the computations should be revised using an improved value of dead load. An accurate estimate of dead load is particularly important when spans are long, say over 75 ft ( 22.9 m ), because dead load constitutes a major portion of the design load.Live loads associated with building use are specific items of equipment and occupants in a certain area of a building, building codes specify values of uniform live for which members are to be designed.After the structure has been sized for vertical load, it is checked for wind in combination with dead and live load as specified in the code. Wind loads do not usually control the size of members in building less than 16 to 18 stories, but for tall buildings wind loads become significant and cause large forces to develop in the structures. Under these conditions economy can be achieved only by selecting a structural system that is able to transfer horizontal loads into the ground efficiently.钢筋混凝土在每一个国家，混凝土及钢筋混凝土都被用来作为建筑材料。
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。
混凝土英文论文
Development of Green High Performance Concrete for SustainableDevelopment0706121 29 刘海庆Abstract: With the fast development of society and economy an important factor that affects social and economicdevelopment is environmental pollution. In face of reduction of the natural resources and the growing problem ofenvironmental pollution, the ordinary concrete has not been fit with the need of the social economy; the perfor-mances of concrete are required improvement. So the development of the concrete materials is generally considered with environmental protection, energy conservation, resource saving and the green high performance concrete is developed. The green high performance concrete that is developed in recent years is a new building material. The concept and features of green high performance concrete are introduced, then the categories and current application of it are analyzed and exist problems are proposed, finally it is concluded that the development of green high per-formance concrete is the only way for the sustainable development of the concrete materials.Keywords:green high performance concrete; environmental pollution; sustainable development CLC: TU528 Document code: A Article ID: 1672-2132(2010)Suppl.-0432-040 IntroductionConcrete is the most widely used and the greatest amount of building materials in the con-struction area. However, extensive use of concrete has destroyed unprecedented natural resources so that resources and energy appear crisis. Concrete in the 21st.century not only meets with the re-quirements of the structure, but also minimizes asmuch as possible the damage to the ecological envi-ronment to the need of sustainable development.So, developing the green high performance con-crete is the need of the sustainable develop-ment.1 Connotation and features of green high performance concretenWu Zongwei, academician of Chinese academy of engineering, first proposed the concept of con-crete and he pointed out the green high perfor-mance concrete was the direction of concrete devel-opment. Researchers consider the green high performance concrete should follow conditions as follows:(1) Cement used must be green cement. Sand and stone should be exploited orderly and withoutdamaging the environment.(2) Cement consumption should be saved tothe greatest extent in order to reduce by-products during the course of producing cement, for exam-ple, CO2, SO2, and NO2and so on.(3) Agricultural and industrial waste residueprocessed should be mixed more, such as, ground-ed slag, high-quality fly ash, silica fume and rice husk, to reduce cement, protect environment and improve concrete durability.(4) Industrial waste liquid should be used a lot, especially; water reducing agent made by black paper waste liquid and other composite addi-tive developed should be mixed to help dealing with other liquid.(5) Concrete should be mixed in the mixing station to reduce waste, dust and waster water of mixing concrete in site and waste and water recy-cling should be strengthened.(6) Through enhancing the strength, reduc-ing cross-sectional area or volume of structure, re-ducing concrete volume, cement, sand and stone can be saved. By improving durability of concrete,service life of structure can be lengthened and re-pair and reconstruction cost are further saved andthe indiscriminate use of natural resources will be reduced.(7) A lot of demolition waste should be recy-cled and recycled aggregate concrete should be de-veloped.The concept of green high performance con-crete is to strengthen people′s green awareness and to play an important role of energy saving and en-vironmental protection. It is concluded that the de-velopment of green high performance concrete is the only way for the sustainable development of concrete.2 Classification of the green high performance concrete2.1 Ecological environment-friendly concreteTo meet with the requirements of high strength and high durability, traditional concrete is always in pursuit of its compactness, which will cause concrete structures (lots of buildings and rigid pavement and so on) lack of permeability and permeability, exacerbate urban heat island effect,deteriorate human living environment. So rainwa-ter can not penetrate so that it lowers ground-wa-ter table in the city and affects growth of the sur-face plant, in a result, causes urban ecological sys-tem disorder. Because concrete color is gray, living space built in concrete gives a rough, hard, cold,dark feeling. So it is concluded that the develop-ment of ecological environment-friendly concrete is the only way to solve these problems. Another, e-cological environment-friendly concrete can be di-vided into plant concrete and water-permeability concrete according to different functions.2.2 Recycled aggregate concreteConcrete from the old buildings or structures can be divided into coarse and fine aggregate through breaking and this aggregate take place of some sand and gravel. So this is considered as re-cycled aggregate concrete. The use of recycled ag-gregate has been viewed as one of main measures in the development of green concrete.2.3 High-volume fly ash high performance con-creteFly ash mixed can improve concrete’s strength, impermeability and frost resistance,lower shrinkage; inhibit the effect of the alkali-ag-gregate reaction. High performance concrete which is mixed a great deal of fly ash and the morphologi-cal effects, micro-aggregate effects, volcanic ash effects of fly ash are used fully will lead to greater economic and environmental benefits.2.4 Environmentally mitigatable concrete(1) Environment-protecting concrete: the dif-ferences in composition between this concrete and traditional concrete are that a lot of solid waste,industrial waste residue, waste brick, concrete and solid rubbish and so on and additive produced through industrial waste liquid are mixed by taking certain technical measures to achieve all kinds of waste recycling and reduce environment pollution.(2) Energy-saving concrete: high temperature calcinations siliceous materials (clay or shale) and calcium raw material are needed in the course of ce-ment production, which will consume a large amount of energy. If concrete are prepared through non-burned cement, energy consumption can be reduced significantly.(3) Self-compacting concrete: self-compacting concrete is vibrated and compacted through self-weight. Because of this concrete has sufficient co-hesion so as to ensure disengagement in theprocess of pouring, a large amount of powder are required.3 Engineering application of green high performance concreteThe history of green high performance con-crete is not long, but it has obvious advantages and is paid attention to at home and abroad. Because concrete has been used widely as structural materi-al to date, appearance of green high performance concrete will become the main building structure materials in the 21st.century. Concrete strength in Chicago′s 311 South-walker Building in America with 295m height and 71 layers was C95. 40 mil-lion m3high performance concrete was used in both anchor piers of Akashi Kaikyo Bridge which was the longest suspension bridge at that time.The use of high green performance concretewas started late in China, especially the serious de-fects of the overpass in the Beijing and Tianjin re-gion arouse great concern in the engineering area.Research and application of green high perfor-mance concrete are increasing little by little.C80 high performance concrete are used in high-rise buildings and Jingan Center Building in Shang-hai.4 Existing problems of green high performance concrete4.1 Cost issuesThe cost of concrete is increased by 50% or more because used raw materials, the production and management level and production lines are raised. For example, collecting and preparing re-cycling aggregate must cost a certain machinery and equipment and manpower for recycled con-crete. From the point of economic indicators, the production of recycled aggregate is few profits, no profit, even deficit. If the production of recycled aggregate maintains a certain profit, its retail price will inevitably higher than the natural aggregate.Therefore, it is difficult to be accepted by users.4.2 Early crackingIn recent years cracking of concrete has be-come a hot topic at home and abroad and high per-formance concrete is no exception. That is, crackof concrete is very common. Many factors that in-fluence early cracking of concrete are as follows:self-shrinkage, drying shrinkage, earl y elastic modulus, tensile strength, ultimate tensile strain,creep, water evaporation rate, structural con-straint degree and so on.4.3 Mix problemThe same absolute volume is used with con-ventional concrete. After mixes of various compo-nents are determined, the performance require-ments are proved through experiments. The mix design of green high performance concrete is more difficult than that of common concrete. Comparing with mix design of conventional concrete, the mix design parameters of green high performance con-crete are smaller, such as, less than 0.4~0.42 water-cement ratio, less than 25mm the largest stone diameter (less than 20 mm or even 15 mm),2.6~3.0 sand fineness modulus, 42.5 concretes trength grade (ISO). So mix design will be sim-plified.5 ConclusionThe research of the green high performance technology in China is still in primary stage and the current research is not enough to conclude the laws that directly guide production. So the research and development of green high performance concrete should be increased greatly andquality standards and production specifications should be drawn up.In a word, we should attach great importance to green issues of concrete because these are related to our human survival and development. Through constant exploration and research, it is firmly be-lieved that the green high performance concrete is the only way for the sustainable development of the concrete materials.Reference:[1] CEB-FIP. Environment Design [R]. Lausanne: [s.n.],2004.[2]Malhotra V M. Introduction: Sustainable develop-ment and concrete technology [J].Concrete interna-tional,2002, 24(7):22.[3]吴中伟.绿色高性能混凝土——混凝土的发展方向[J].混凝土与水泥制品,1998,(1):3-6.[4]鄢朝勇.混凝土材料的可持续发展与粉煤灰绿色高性能混凝土[J].国外建材科技,2005,(4):5-7.[5] 王立久,汪振双,赵善宇.绿色生态混凝土技术的研究现状与发展[J].混凝土. 2009,(7):1-3.[6] Kumar M P. Reducing the environmental impact of concrete [J]. Concrete International,2001, 23(10):61-66.[7] Kumar M P. Greening of the concrete industry for sustainable development [J]. ConcreteInternational,2002, 24(7):23-28.[8] 王淑萍,王思远,张春,等.高性能混凝土的研究现状和发展应用[J].北方交通,2007,(4):47-50.[9]周士琼,李益进,尹健,等.复合超细粉煤灰与特种混凝土技术的开发与应用[J].铁道科学与工程学报,2004,(2):39-45.。
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。
混凝土制备工艺及流程英文版
混凝土制备工艺及流程英文版Concrete is a versatile and durable building materialthat is used in a wide variety of construction projects. The process of preparing concrete involves several key steps to ensure that the final product is strong, durable, and able to withstand the rigors of use.The first step in preparing concrete is to gather the necessary materials. This includes Portland cement, sand, gravel, and water. These materials are carefully measured and mixed together in the correct proportions to create a uniform mixture.Once the materials are mixed together, the next step is to pour the concrete into molds or forms. This allows the concrete to take on the desired shape and size for the specific project. The concrete must be carefully leveled andsmoothed to ensure that the final product is uniform and free of defects.After the concrete has been poured and formed, it must be allowed to cure. This process involves keeping the concrete at the correct temperature and humidity levels to ensure that it sets and hardens properly. Curing can take several days to complete, depending on the specific type of concrete being used.Once the concrete has cured, it can be removed from the molds or forms and is ready for use in construction projects. It is important to handle and transport the concrete with care to avoid any damage to the final product.In conclusion, the preparation of concrete is a careful and precise process that involves several key steps. By following these steps, construction professionals can create high-quality concrete that is strong, durable, and able to withstand the demands of use in a wide variety of projects.。
土木工程混凝土强度中英文对照外文翻译文献
<文献翻译一：原文>Strength of Concrete in Slabs, Investigates along Direction of Concreting ABSTRACTIn theory of concrete it is assumed that concrete composites are isotropic on a macro scale. For example, it is assumed that a floor slab’s or a beam’s streng th is identical in all directions and its nonhomogeneity is random. Hence neither calculations of the load-bearing capacity of structural components nor the techniques of investigating concrete in structure in situ take into account to a sufficient degree the fact that the assumption about concrete isotropy is overly optimistic. The present research shows that variation in concrete strength along the direction of concreting has not only a qualitative effect (as is commonly believed), but also a significant quantitative effect. This indicates that concrete is a composite which has not been fully understood yet. The paper presents evaluations of ordinary concrete (OC) homogeneity along component thickness along the direction of concreting. The ultrasonic method and modified exponential heads with a point contact with concrete were used in the investigations [1-3].Keywords: Concrete; Compressive Strength of Concrete; Non-Destructive1. IntroductionIn a building structure there are components which are expected to have special properties but not necessarily in the whole cross section. Components under bending, such as beams and floor slabs are generally compressed in their upper zone and the concrete’s compressive strength is vital mainly in this zone. The components are usually moulded in the same position in which they later remain in service, i.e. with their upper zone under compression. Concrete in the upper zone is expected to be slightly weaker than in the lower zone, but it is unclear how much weaker [4,5]. Also flooring slabs in production halls are most exposed to abrasion and impact loads in their upper zone which is not their strongest part. It is known from practice that industrial floors belong to the most often damaged building components.When reinforced concrete beams or floor slabs are to be tested they can be accessed only from their undersides and so only the bottom parts are tested and on this basis conclusions are drawn about the strength of the concrete in the whole cross section, including in the compressed upper zone. Thus a question arises: how large are the errors committed in this kind of investigations?In order to answer the above and other questions, tests of the strength of concrete in various structural components, especially in horizontally concreted slabs, were carried out. The variation of strength along the thickness of the components was analyzed.2. Research SignificanceThe research results presented in the paper show that the compressive strength of concrete in horizontally formed structural elements varies along their thickness. In the top zone the strength is by 25% - 30% lower than the strength in the middle zone, and it can be by as much as 100% lower than the strength in the bottom zone. The observations are based on the results of nondestructive tests carried out on drill cores taken from the structure, and verified by a destructive method. It is interesting to note that despite the great advances in concrete technology, the variation in compressive strength along the thickness of structural elements is characteristic of both old (over 60 years old) concretes and contemporary ordinary concretes.3. Test MethodologyBefore Concrete strength was tested by the ultrasonic method using exponential heads with a point contact with concrete. The detailed specifications of the heads can be found in [2,3]. The heads’ frequency was 40 and 100 kHz and the diameter of their concentrators amounted to 1 mm.In order to determine the real strength distributions in the existing structures, cylindrical cores 80 mm or 114 mm diameter (Figure 2) were drilled from them in the direction of concreting. Then specimens with their height equal to their diameter were cut out of the cores.Ultrasonic measurements were performed on the cores according to the scheme shown in Figure3. Ultrasonic pulses (pings) were passed through in two perpendicular directions I and II in planes spaced every 10 mm. In this way one could determine how ping velocity varied along the core’s height, i.e. along the thickness of the tested component.In both test directions ping pass times were determined and velocities CL were calculated. The velocities from the two directions in a tested measurement plane were averaged.Subsequently, specimens with their height equal to their diameter of 80 mm were cut out of the cores. Aver-age ultrasonic pulse velocity CL for the specimen’s central zone was correlated with fatigue strength fc determined by destructive tests carried out in a strength tester.For the different concretes different correlation curves with a linear, exponential or power equation were obtained. Exemplary correlation curve equations are given below:Lc c L c C f L f C f 38.1exp 0951.01.003.56705.232621.4=⋅=-⨯=where:fc —the compressive strength of concrete MPa,CL —ping velocity km/s.The determined correlation curve was used to calculate the strength of concrete in each tested core cross section and the results are presented in the form of graphs illustrating concrete strength distribution along the thickness of the tested component. 4. Investigation of Concrete in Industrial FloorsAfter Floor in sugar factory’s raw materials storage hall Concrete in an industrial floor must have particularly good characteristics in the top layer. Since it was to be loaded with warehouse trucks and stored sugar beets and frequently washed the investigated concrete floor (built in 1944) was designed as consisting of a 150 mm thick underlay and a 50 mm thick surface layer and made of concrete with a strength of 20 MPa (concrete A).As part of the investigations eight cores, each 80 mm in diameter, were drilled from the floor. The investigations showed significant departures from the design. The concrete subfloor’s thickness varied from 40 to 150 mm. The surface layer was not made of concrete, but of cement mortar with sand used as the aggregate. Also the thickness of this layer was uneven, varying from 40 to 122mm. After the ultrasonic tests specimens with their height equal to their diameter of 80 mm were cut out of the cores. Two scaling curves: one for the surface layer and the other for the bottom concrete layer were determined.A characteristic concrete compressive strength distribution along the floor’s thickness is shown in Figure 4.Strength in the upper zone is much lower than in thelower zone: ranging from 4.7 to 9.8 MPa for the mortar and from 13.9 to 29.0 MPa for the concrete layer. The very low strength of the upper layer of mortar is the result of strong porosity caused by air bubbles escaping upwards during the vibration of concrete. Figure 5 shows t he specimen’s porous top surface.Floor in warehouse hall with forklift truck transport The floor was built in 1998. Cellular concrete was used as for the underlay and the 150 mm thick surface layer was made of ordinary concrete with fibre (steel wires) reinforcement (concrete B). Cores 80 mm high and 80 mm in diameter were drilled from the surface layer. Ultrasonic measurements and destructive tests were performed as described above. Also the test results were handled in a similar way. An exemplary strength distribution along the floor’s thickness is shown in Figure 6.5. ConclusionsTests of ordinary concretes show unexpectedly greatly reduced strength in the upper zone of horizontally moulded structural components. This is to a large degree due to the vibration of concrete as a result of which coarse aggregate displaces downwards making the lower layers more compact while air moves upwards aerating the upper layers and thereby increasing their porosity. The increase in the concrete’s porosity results in a large drop in its compressive strength. Thanks to the use of the ultrasonic method and probes with exponential concentrators it could be demonstrated how the compressive strength of ordinary concrete is distributed along the thickness of structural components in building structures. It became apparent that the reduction in compressive strength in the compressed zone of structural components under bending and in industrial concrete floors can be very large (amounting to as much as 50% of the strength of t he slab’s lower zone). Therefore this phenomenon should be taken into account at the stage of calculating slabs, reinforced concrete beams and industrial floors [6].The results of the presented investigations apply to ordinary concretes (OC) which are increasingly supplanted by self-compacting concretes (SCC) and high-performance concretes (HPC). Since no intensive vibration is required to mould structures from such concretes one can expect that they are much more homogenous along their thickness [7]. This will be known once the ongoing experimental research is completed.Bohdan StawiskiStrength of Concrete in Slabs, Investigates along Direction of Concreting[D]Institute of Building Engineering, Wroclaw University of Technology Wybrzeze Wyspianskiego, Wroclaw, Poland Received October 15, 2011; revised November 21, 2011; accepted November 30, 2011<文献翻译一：译文>混凝土强度与混凝土浇筑方向关系的研究摘要从理论上看，假设混凝土复合材料是各项同性的从宏观尺度上讲。
土木工程类外文文献翻译---钢筋混凝土可编辑
土木工程类外文文献翻译---钢筋混凝土外文文献翻译院系_________________________班级_________________________姓名_________________________指导教师_________________________2012年2月20 日2 外文翻译21 Reinforced ConcretePlain concrete is formed from a hardened mixture of cement water fine aggregate coarse aggregate crushed stone or gravel air and often other admixtures The plastic mix is placed and consolidated in the formwork then cured to facilitate the acceleration of the chemical hydration reaction lf the cementwater mix resulting in hardened concrete The finished product has high compressive strength and low resistance to tension such that its tensile strength is approximately one tenth lf its compressive strength Consequently tensile and shear reinforcement in the tensile regions of sections has to be provided to compensate for the weak tension regions in the reinforced concrete elementIt is this deviation in the composition of a reinforces concrete section from the homogeneity of standard wood or steel sections that requires a modified approach to the basic principles of structural design The two components of the heterogeneous reinforced concrete section are to be so arranged and proportioned that optimal use is made of the materials involved This is possible because concrete can easily be givenany desired shape by placing and compacting the wet mixture of the constituent ingredients are properly proportioned the finished product becomes strong durable and in combination with the reinforcing bars adaptable for use as main members of any structural system The techniques necessary for placing concrete depend on the type of member to be cast that is whether it is a column a bean a wall a slab a foundation a mass columns or an extension of previously placed and hardened concrete For beams columns and walls the forms should be well oiled after cleaning them and the reinforcement should be cleared of rust and other harmful materials In foundations the earth should be compacted and thoroughly moistened to about 6 in in depth to avoid absorption of the moisture present in the wet concrete Concrete should always be placed in horizontal layers which are compacted by means of high frequency power-driven vibrators of either the immersion or external type as the case requires unless it is placed by pumping It must be kept in mind however that over vibration can be harmful since it could cause segregation of the aggregate and bleeding of the concreteHydration of the cement takes place in the presence of moisture at temperatures above 50°F It is necessary to maintain such a condition in order that the chemical hydration reaction can take place If drying is too rapid surface cracking takes place This would result in reduction of concrete strength due to cracking as well as the failure to attain full chemical hydrationIt is clear that a large number of parameters have to be dealt with in proportioning a reinforced concrete element such as geometrical widthdepth area of reinforcement steel strain concrete strain steel stress and so on Consequently trial and adjustment is necessary in the choice of concrete sections with assumptions based on conditions at site availability of the constituent materials particular demands of the owners architectural and headroom requirements the applicable codes and environmental reinforced concrete is often a site-constructed composite in contrast to the standard mill-fabricated beam and column sections in steel structuresA trial section has to be chosen for each critical location in a structural system The trial section has to be analyzed to determine if its nominal resisting strength is adequate to carry the applied factored load Since more than one trial is often necessary to arrive at the required section the first design input step generates into a series of trial-and-adjustment analysesThe trial-and –adjustment procedures for the choice of a concrete section lead to the convergence of analysis and design Hence every design is an analysis once a trial section is chosen The availability of handbooks charts and personal computers and programs supports this approach as a more efficient compact and speedy instructional method compared with the traditional approach of treating the analysis of reinforced concrete separately from pure design22 EarthworkBecause earthmoving methods and costs change more quickly than those in any other branch of civil engineering this is a field where there are real opportunities for the enthusiast In 1935 most of the methods now inuse for carrying and excavating earth with rubber-tyred equipment did not exist Most earth was moved by narrow rail track now relatively rare and the main methods of excavation with face shovel backacter or dragline or grab though they are still widely used are only a few of the many current methods To keep his knowledge of earthmoving equipment up to date an engineer must therefore spend tine studying modern machines Generally the only reliable up-to-date information on excavators loaders and transport is obtainable from the makersEarthworks or earthmoving means cutting into ground where its surface is too high cuts and dumping the earth in other places where the surface is too low fills Toreduce earthwork costs the volume of the fills should be equal to the volume of the cuts and wherever possible the cuts should be placednear to fills of equal volume so as to reduce transport and double handlingof the fill This work of earthwork design falls on the engineer who lays out the road since it is the layout of the earthwork more than anything else which decides its cheapness From the available maps ahd levels the engineering must try to reach as many decisions as possible in the drawing office by drawing cross sections of the earthwork On the site when further information becomes available he can make changes in jis sections and layoutbut the drawing lffice work will not have been lost It will have helped him to reach the best solution in the shortest timeThe cheapest way of moving earth is to take it directly out of the cut and drop it as fill with the same machine This is not always possible but when it canbe done it is ideal being both quick and cheap Draglinesbulldozers and face shovels an do this The largest radius is obtained with the draglineand the largest tonnage of earth is moved by the bulldozer though only over short distancesThe disadvantages of the dragline are that it must dig below itself it cannot dig with force into compacted material it cannot dig on steep slopws and its dumping and digging are not accurate Face shovels are between bulldozers and draglines having a larger radius of action than bulldozers but less than draglines They are anle to dig into a vertical cliff face in a way which would be dangerous tor a bulldozer operator and impossible for a dragline Each piece of equipment should be level of their tracks and for deep digs in compact material a backacter is most useful but its dumping radius is considerably less than that of the same escavator fitted with a face shovelRubber-tyred bowl scrapers are indispensable for fairly level digging where the distance of transport is too much tor a dragline or face shovel They can dig the material deeply but only below themselves to a fairly flat surface carry it hundreds of meters if need be then drop it and level it roughly during the dumping For hard digging it is often found economical to keep a pusher tractor wheeled or tracked on the digging site to push each scraper as it returns to dig As soon as the scraper is fullthe pusher tractor returns to the beginning of the dig to heop to help the nest scraperBowl scrapers are often extremely powerful machinesmany makers build scrapers of 8 cubic meters struck capacity which carry 10 m 3 heaped The largest self-propelled scrapers are of 19 m 3 struck capacity 25 m 3 heaped and they are driven by a tractor engine of 430 horse-powersDumpers are probably the commonest rubber-tyred transport since they can also conveniently be used for carrying concrete or other building materials Dumpers have the earth container over the front axle on large rubber-tyred wheels and the container tips forwards on most types though in articulated dumpers the direction of tip can be widely varied The smallest dumpers have a capacity of about 05 m 3 and the largest standard types are of about 45 m 3 Special types include the self-loading dumper of up to 4 m 3 and the articulated type of about 05 m 3 The distinction between dumpers and dump trucks must be remembered dumpers tip forwards and the driver sits behind the load Dump trucks are heavy strengthened tipping lorries the driver travels in front lf the load and the load is dumped behind him so they are sometimes called rear-dump trucks23 Safety of StructuresThe principal scope of specifications is to provide general principles and computational methods in order to verify safety of structures The safety factor which according to modern trends is independent of the nature and combination of the materials used can usually be defined as the ratio between the conditions This ratio is also proportional to the inverse of the probability risk of failure of the structureFailure has to be considered not only as overall collapse of the structure but also as unserviceability or according to a more precise Common definition As the reaching of a limit state which causes the construction not to accomplish the task it was designed for There are two categories of limit state1 Ultimate limit sate which corresponds to the highest value of the load-bearing capacity Examples include local buckling or global instability of the structure failure of some sections and subsequent transformation of the structure into a mechanism failure by fatigue elastic or plastic deformation or creep that cause a substantial change of the geometry of the structure and sensitivity of the structure to alternating loads to fire and to explosions2 Service limit states which are functions of the use and durability of the structure Examples include excessive deformations and displacements without instability early or excessive cracks large vibrations and corrosionComputational methods used to verify structures with respect to the different safety conditions can be separated into1 Deterministic methods in which the main parameters are considered as nonrandom parameters2 Probabilistic methods in which the main parameters are considered as random parametersAlternatively with respect to the different use of factors of safety computational methods can be separated into1 Allowable stress method in which the stresses computed under imum loads are compared with the strength of the material reduced by given safety factors2 Limit states method in which the structure may be proportioned on the basis of its imum strength This strength as determined by rational analysis shall not be less than that required to support a factored loadequal to the sum of the factored live load and dead load ultimate state The stresses corresponding to working service conditions with unfactored live and dead loads are compared with prescribed values service limit state From the four possible combinations of the first two and second two methods we can obtain some useful computational methods Generally two combinations prevail1 deterministic methods which make use of allowable stresses2 Probabilistic methods which make use of limit statesThe main advantage of probabilistic approaches is that at least in theory it is possible to scientifically take into account all random factors of safety which are then combined to define the safety factor probabilistic approaches depend upon1 Random distribution of strength of materials with respect to the conditions of fabrication and erection scatter of the values of mechanical properties through out the structure2 Uncertainty of the geometry of the cross-section sand of the structure faults and imperfections due to fabrication and erection of the structure3 Uncertainty of the predicted live loads and dead loads acting on the structure4 Uncertainty related to the approximation of the computational method used deviation of the actual stresses from computed stresses Furthermore probabilistic theories mean that the allowable risk can be based on several factors such as1 Importance of the construction and gravity of the damage byits failure2 Number of human lives which can be threatened by this failure3 Possibility andor likelihood of repairing the structure4 Predicted life of the structureAll these factors are related to economic and social considerations such as1 Initial cost of the construction2 Aortization funds for the duration of the construction3 Cost of physical and material damage due to the failure of the construction4 Adverse impact on society5 Moral and psychological viewsThe definition of all these parameters for a given safety factor allows construction at the optimum cost However the difficulty of carrying out a complete probabilistic analysis has to be taken into account For such an analysis the laws of the distribution of the live load and its induced stresses of the scatter of mechanical properties of materials and of the geometry of the cross-sections and the structure have to be known Furthermore it is difficult to interpret the interaction between the law of distribution of strength and that of stresses because both depend upon the nature of the material on the cross-sections and upon the load acting on the structure These practical difficulties can be overcome in two ways The first is to apply different safety factors to the material and to the loads without necessarily adopting the probabilistic criterion The second is an approximate probabilistic method which introduces some simplifyingassumptions semi-probabilistic methods1 中文翻译11钢筋混凝土素混凝土是由水泥水细骨料粗骨料碎石或卵石空气通常还有其他外加剂等经过凝固硬化而成将可塑的混凝土拌合物注入到模板内并将其捣实然后进行养护以加速水泥与水的水化反应最后获得硬化的混凝土其最终制成品具有较高的抗压强度和较低的抗拉强度其抗拉强度约为抗压强度的十分之一因此截面的受拉区必须配置抗拉钢筋和抗剪钢筋以增加钢筋混凝土构件中较弱的受拉区的强度由于钢筋混凝土截面在均质性上与标准的木材或钢的截面存在着差异因此需要对结构设计的基本原理进行修改将钢筋混凝土这种非均质截面的两种组成部分按一定比例适当布置可以最好的利用这两种材料这一要求是可以达到的因混凝土由配料搅拌成湿拌合物经过振捣并凝固硬化可以做成任何一种需要的形状如果拌制混凝土的各种材料配合比恰当则混凝土制成品的强度较高经久耐用配置钢筋后可以作为任何结构体系的主要构件浇筑混凝土所需要的技术取决于即将浇筑的构件类型诸如柱梁墙板基础大体积混凝土水坝或者继续延长已浇筑完毕并且已经凝固的混凝土等对于梁柱墙等构件当模板清理干净后应该在其上涂油钢筋表面的锈及其他有害物质也应该被清除干净浇筑基础前应将坑底土夯实并用水浸湿6英寸以免土壤从新浇的混凝土中吸收水分一般情况下除使用混凝土泵浇筑外混凝土都应在水平方向分层浇筑并使用插入式或表面式高频电动振捣器捣实必须记住过分的振捣将导致骨料离析和混凝土泌浆等现象因而是有害的水泥的水化作用发生在有水分存在而且气温在50°F以上的条件下为了保证水泥的水化作用得以进行必须具备上述条件如果干燥过快则会出现表面裂缝这将有损与混凝土的强度同时也会影响到水泥水化作用的充分进行设计钢筋混凝土构件时显然需要处理大量的参数诸如宽度高度等几何尺寸配筋的面积钢筋的应变和混凝土的应变钢筋的应力等等因此在选择混凝土截面时需要进行试算并作调整根据施工现场条件混凝土原材料的供应情况业主提出的特殊要求对建筑和净空高度的要求所用的设计规范以及建筑物周围环境条件等最后确定截面钢筋混凝土通常是现场浇注的合成材料它与在工厂中制造的标准的钢结构梁柱等不同因此对于上面所提到的一系列因素必须予以考虑对结构体系的各个部位均需选定试算截面并进行验算以确定该截面的名义强度是否足以承受所作用的计算荷载由于经常需要进行多次试算才能求出所需的截面因此设计时第一次采用的数值将导致一系列的试算与调整工作选择混凝土截面时采用试算与调整过程可以使复核与设计结合在一起因此当试算截面选定后每次设计都是对截面进行复核手册图表和微型计算机以及专用程序的使用使这种设计方法更为简捷有效而传统的方法则是把钢筋混凝土的复核与单纯的设计分别进行处理12土方工程由于和土木工程中任何其他工种的施工方法与费用相比较土方挖运的施工方法与费用的变化都要快得多因此对于有事业心的人来说土方工程是一个可以大有作为的领域在1935年目前采用的利用轮胎式机械设备进行土方挖运的方法大多数还没有出现那是大部分土方是采用窄轨铁路运输在这目前来说是很少采用的当时主要的开挖方式是使用正铲反铲拉铲或抓斗等挖土机尽管这些机械目前仍然在广泛应用但是它们只不过是目前所采用的许多方法中的一小部分因此一个工程师为了使自己在土方挖运设备方面的知识跟得上时代的发展他应当花费一些时间去研究现代的机械一般说来有关挖土机装载机和运输机械的唯一可靠而又最新的资料可以从制造厂商处获得土方工程或土方挖运工程指的是把地表面过高处的土壤挖去挖方并把它倾卸到地表面过低的其他地方填方为了降低土方工程费用填方量应该等于挖方量而且挖方地点应该尽可能靠近土方量相等的填方地点以减少运输量和填方的二次搬运土方设计这项工作落到了从事道路设计的工程师的身上因为土方工程的设计比其他任何工作更能决定工程造价是否低廉根据现有的地图和标高道路工程师应在设计绘图室中的工作也并不是徒劳的它将帮助他在最短的时间内获得最好的方案费用最低的运土方法是用同一台机械直接挖方取土并且卸土作为填方这并不是经常可以做到的但是如果能够做到则是很理想的因为这样做既快捷又省钱拉铲挖土机推土机和正铲挖土机都能做到这点拉铲挖土机的工作半径最大推土机所推运的图的数量最多只是运输距离很短拉铲挖土机的缺点是只能挖比它本身低的土不能施加压力挖入压实的土壤内不能在陡坡上挖土而且挖卸都不准确正铲挖土机介于推土机和拉铲挖土机的之间其作用半径大于推土机但小于拉铲挖土机正铲挖土机能挖取竖直陡峭的工作面这种方式对推土机司机来说是危险的而对拉铲挖土机则是不可能的每种机械设备应该进行最适合它的性能的作业正铲挖土机不能挖比其停机平面低很多的土而深挖坚实的土壤时反铲挖土机最适用但其卸料半径比起装有正铲的同一挖土机的卸料半径则要小很多在比较平坦的场地开挖如果用拉铲或正铲挖土机运输距离太远时则装有轮胎式的斗式铲运机就是比不可少的它能在比较平的地面上挖较深的土但只能挖机械本身下面的土需要时可以将土运至几百米远然后卸土并在卸土的过程中把土大致铲平在挖掘硬土时人们发现在开挖场地经常用一辆助推拖拉机轮式或履带式对返回挖土的铲运机进行助推这种施工方法是经济的一旦铲运机装满助推拖拉机就回到开挖的地点去帮助下一台铲运机斗式铲运机通常是功率非常大的机械许多厂家制造的铲运机铲斗容量为8 m3满载时可达10 m3最大的自行式铲运机铲斗容量为19立方米满载时为25 m3由430马力的牵引发动机驱动翻斗机可能是使用最为普遍的轮胎式运输设备因为它们还可以被用来送混凝土或者其他建筑材料翻斗车的车斗位于大橡胶轮胎车轮前轴的上方尽管铰接式翻斗车的卸料方向有很多种但大多数车斗是向前翻转的最小的翻斗车的容量大约为05立方米而最大的标准型翻斗车的容量大约为45m3特殊型式的翻斗车包括容量为4 m3的自装式翻斗车和容量约为05 m3的铰接式翻斗车必须记住翻斗车与自卸卡车之间的区别翻斗车车斗向前倾翻而司机坐在后方卸载因此有时被称为后卸卡车13结构的安全度规范的主要目的是提供一般性的设计原理和计算方法以便验算结构的安全度就目前的趋势而言安全系数与所使用的材料性质及其组织情况无关通常把它定义为发生破坏的条件与结构可预料的最不利的工作条件之比值这个比值还与结构的破坏概率危险率成反比破坏不仅仅指结构的整体破坏而且还指结构不能正常的使用或者用更为确切的话来说把破坏看成是结构已经达到不能继续承担其设计荷载的极限状态通常有两种类型的极限状态即1强度极限状态它相当于结构能够达到的最大承载能力其例子包括结构的局部屈曲和整体不稳定性某此界面失效随后结构转变为机构疲劳破坏引起结构几何形状显著变化的弹性变形或塑性变形或徐变结构对交变荷载火灾和爆炸的敏感性2使用极限状态它对应着结构的使用功能和耐久性器例子包括结构失稳之前的过大变形和位移早期开裂或过大的裂缝较大的振动和腐蚀根据不同的安全度条件可以把结构验算所采用的计算方法分成1确定性的方法在这种方法中把主要参数看作非随机参数2概率方法在这种方法中主要参数被认为是随机参数此外根据安全系数的不同用途可以把结构的计算方法分为1容许应力法在这种方法中把结构承受最大荷载时计算得到的应力与经过按规定的安全系数进行折减后的材料强度作比较2极限状态法在这种方法中结构的工作状态是以其最大强度为依据来衡量的由理论分析确定的这一最大强度应不小于结构承受计算荷载所算得的强度极限状态计算荷载等于分别乘以荷载系数的活载与恒载之和把对应于不乘以荷载系数的活载和恒载的工作使用条件的应力与规定值使用极限状态相比较根据前两种方法和后两种方法的四种可能组合我们可以得到一些实用的计算方法通常采用下面两种计算方法确定性的方法这种方法采用容许应力概率方法这种方法采用极限状态至少在理论上概率法的主要优点是可以科学的考虑所有随机安全系数然后将这些随机安全系数组合成确定的安全系数概率法取决于1制作和安装过程中材料强度的随机分布整个结构的力学性能数值的分散性2截面和结构几何尺寸的不确定性由结构制作和安装造成的误差和缺陷而引起的对作用在结构上的活载和恒载的预测的不确定性所采用的近似计算方法有关的不精确性实际应力与计算应力的偏差此外概率理论意味着可以基于下面几个因素来确定允许的危险率例如建筑物的重要性和建筑物破坏造成的危害性2由于建筑物破坏使生活受到威胁的人数3修复建筑的可能性4建筑物的预期寿命所有这些因素均与经济和社会条件有关例如1建筑物的初始建设费2建筑物使用期限内的折旧费3由于建筑物破坏而造成的物质和材料损失费4在社会上造成的不良影响5精神和心理上的考虑就给定的安全系数而论所有这些参数的确定都是以建筑物的最佳成本为依据的但是应该考虑到进行全概率分析的困难对于这种分析来说应该了解活载及其所引起的盈利的分布规律材料的力学性能的分散性和截面的结构几何尺寸的分散性此外由于强度的分布规律和应力的分布规律之间的相互关系是困难的这些实际困难可以采用两种方法来克服第一种方法对材料和荷载采用不同的安全系数而不需要采用概率准则第二种方法是引入一些而简化假设的近似概率方法半概率方法1建筑工程学院土木工程系土木084班。
混凝土搅拌方法和混凝土搅拌机工艺状态外文文献翻译、中英文翻译
附录Ⅰ：外文翻译混凝土搅拌方法和混凝土搅拌机:工艺状态对于所有材料来说，混凝土的性能是由其微观结构决定的。
它的微观结构由其组成、固化条件以及用于处理混凝土的搅拌方法和搅拌条件决定。
搅拌过程包括搅拌机的类型、物料进入搅拌机的顺序以及搅拌的能量(持续时间和功率)。
不同的搅拌机将会被介绍到一起，并对搅拌方法进行回顾。
此外，还将研究不同搅拌机的优缺点，并对其应用进行研究。
还将介绍搅拌方法对混凝土质量的影响，以及确定搅拌方法的有效性的一些程序。
为了确定最适合某一特定应用的搅拌方法，需要考虑的因素包括建筑工地的位置(与配料厂的距离)、需要的混凝土量、施工进度(每小时需要的混凝土体积)和成本。
然而，主要考虑的是混凝土的质量。
这种质量是由混凝土的性能和搅拌后的材料的同质性决定的。
搅拌机有两大类:间歇式搅拌机和连续搅拌机。
第一类搅拌机间歇性生产混凝土，而第二种类型的混凝土则以恒定的速度连续生产混凝土。
第一种类型需要在每次搅拌循环后完全清空，并清洗干净，重新加载下一批混凝土的材料。
在第二种类型中，当新鲜的混凝土从一端出料时，另一端则同时进料。
所有的鼓式搅拌机都有一个类似于横截面的容机。
叶片连接到活动鼓的内部。
他们的主要目的是在滚筒转动时把材料抬起来。
在每一次旋转中，提升的物质会回到鼓底部的搅拌机中，然后循环再次开始。
可以控制的参数是鼓的转速，在某些搅拌机中，转动轴的倾斜角。
鼓式搅拌机主要有三种: •无倾斜鼓;•扭转鼓;•倾斜鼓。
无倾转鼓式搅拌机意味着滚筒的定向力是固定的。
材料在一端添加，另一端排放。
换向滚筒类似于不倾斜的搅拌机，但相同的开口用于添加成分和排放混凝土。
滚筒在一个方向上旋转，用于搅拌和向相反的方向排放混凝土。
在鼓的内壁上有两种类型的叶片。
当滚筒旋转时，一组将混凝土向上拉向搅拌机中心;第二组叶片将混凝土推向开口，当鼓轮转动时，另一组。
叶片有一个螺旋排列，以获得预期的效果，用于排放和搅拌。
倾斜的圆筒搅拌机的倾斜角度可以是多种多样的。
商砼工艺流程
商砼工艺流程(中英文版)Task Title: Concrete Mixing ProcessThe concrete mixing process is a crucial step in construction that requires precision and accuracy.The first step in this process is to weigh the cement, aggregates, and water.This ensures that the correct proportions are used to create a strong and durable concrete mix.商砼工艺流程是建筑施工中的关键步骤，需要精确和准确。
这一过程的第一步是称量水泥、骨料和水。
这确保了使用正确的比例来创建一种强大和耐用的砼拌合料。
ext, the materials are transported from the weighbridge to the mixing plant.This is where the materials are thoroughly mixed to ensure that the concrete is uniform in color and consistency.The mixing process typically lasts for a few minutes, depending on the type of concrete being produced.然后，材料从称重站运送到拌合站。
在这里，材料被彻底混合，以确保砼的颜色和一致性。
拌合过程通常持续几分钟，具体时间取决于正在生产的砼类型。
Once the concrete is mixed, it is transported to the construction site in mixer trucks.These trucks have rotating drums that keep the concrete constantly mixed during transportation.This helps to prevent the concrete from setting or segregating before it is used in the construction process.一旦砼拌合完成，它会被运送到施工现场的搅拌车中。
混凝土毕业设计论文中英文对照资料外文翻译文献
外文文献及译文目录•1历史•2组成o水泥2.1o 2.2水o 2.3骨料o 2.4化学外加剂o 2.5掺合料和水泥混合o 2.6纤维•3搅拌混凝土•4个特点o 4.1和易o 4.2固化o 4.3强度o 4.4弹性o 4.5扩张和收缩o 4.6开裂▪ 4.6.1收缩裂缝▪ 4.6.2拉裂o 4.7蠕变•5损伤模式o 5.1火灾o 5.2总量扩张o 5.3海水效果o 5.4细菌腐蚀o 5.5化学武器袭击▪ 5.5.1碳化▪ 5.5.2氯化物▪ 5.5.3硫酸盐o 5.6浸出o 5.7人身损害•6种混凝土o 6.1普通混凝土o 6.2高强混凝土o 6.3高性能混凝土o 6.4自密实混凝土o 6.5喷浆o 6.6透水性混凝土o 6.7混凝土蜂窝o 6.8软木复合水泥o 6.9碾压混凝土o 6.10玻璃混凝土o 6.11沥青混凝土•7混凝土测试•8混凝土回收•9使用混凝土结构o9.1大体积混凝土结构o9.2钢筋混凝土结构o9.3预应力混凝土结构•10参见•11参考•12外部链接历史在塞尔维亚,仍然是一个小屋追溯到5600bce已经发现,同一个楼层发红色石灰,沙子和砾石。
金字塔陕西中建千多年前,含有石灰和火山灰.或粘土。
碎石水和泥浆僵硬和发展实力超过时间。
为了确保经济实用的解决方案,既罚款又粗骨料使用,以弥补大部分的混凝土混合物。
砂,天然砾石及碎石,主要用于这一目的。
不过,现在越来越普遍,再生骨料(由建筑,拆卸和挖掘废物)被用作局部代替天然骨料,而一些生产总量包括风冷高炉炉渣和粉煤灰也是不允许的。
装饰石材等石英岩,潆石块或玻璃破碎,有时添加到混凝土表面进行装饰性"的总暴露"完成,流行景观设计师。
化学外加剂化学外加剂现形式的材料粉末或液体,补充了混凝土给它的某些特性没有可与普通混凝土混合物。
在正常情况下使用,外加剂剂量均低于5%的大量水泥,并补充了混凝土当时的配料/混合.最常见的外加剂有:加速器加速水化(硬化)的混凝土。
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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。