混凝土专业毕业论文_外文翻译
混凝土毕业设计外文翻译--保护,预防,修复,改造和升级
外文文献翻译Protection,prevention,repair,renovation and upgrading（摘自《Management of Deteriorating Concrete Structures》Chapter 7作者George Somerville ）7.1 IntroductionThe need to repair concrete structure is not new. Much of the early work involved making good via patch repairs and crack filling, for aesthetic and serviceability reasons[7.1]. As the concrete infrastructure of the mid-20th century matured, there was also a demand to strengthen or upgrade to meet changes in use or increase in loadings. The need to treat cases of corrosion emerged in the 1950s with post-war prefabricated reinforced concrete housing,and many of the references to Chapter 2 detail examples of corrosion in highway structures as the use of de-icing salts increased rapidly in the early 1960s.Reference[7.2] gives some details of this ,and reference [7.3] is a detailed review of the situation in the UK and France with regard to post-tesioned concrete bridges.As durability concerns became more widespread, and consequences of failure more critical, repair became a growth industry, and options available on the market increased significantly in term of principles and approaches, and the individual solutions within each basic approach. This taining over 200 short papers on all aspects of the problem.The literature is full of individual case studies, describing what has been physically done and giving some reasons for selecting a particular option; it is often diffcult to draw general conclusions from these. Such articles, which are also helpful since they provide website addressers,appear most frequently in concrete-related journals such as Concrete from the Concrete Society in the UK. In North America, the various journals of the American Concrete Institute (ACI) do a similar job, and focus on repair is provided by the International Concrete Repair Institute (ICRI),which publishs a bimonthly Bulletin, and whose website gives details of available publications in the USA; generally, these are either guidance documents, or complications of articles on particular topics.There are aslo guidance documents available on individual repair, protection and upgrading methods, which explain the principles involved and are strong on the “how to …” aspects of the problem. Some examples of these can be obtained from the ICRIwebsite for North America, and reference[7.4-7.9] are similar publications available from the Concrete Society in the UK. The Concrete Society portfolio is augmented by other reports on test methods and diagnosis,and on how to enhance durability in new constructions; Technical Report 61 [7.10] is an example of the latter, where much of the detailed information is transferable to the repair and renovation situation. The Concrete RepairAssocication in the UK also has a website.The above brief rewiew is intended to show that there is quite a lot of information available on repair and renovation methods and also to indicate the nature of that information. It can become dated quite quickly however, as the technology is improved and new techniques are introduced. Moreover,, the nature and format of the information make it difficult to compare the technical and economic merits of alternative approaches- essential information to the owner when making a choice. This situation is now changing, with serious attempts being made to develop a systematic scientific basis for classifying repair and renovation methods, supported by sound specification and test methods. The emergence of EN 1504 is a prime example of that, and will be referred to strongly in later sections of this chapter.The final major missing link from the data bases is the lack of indepth feedback on real performation in the field over relevant periods of time. How does this compare with claims and expectations? Again this is changing, as typified by Figures 2.13-2.16 ,taken from the paper by Tilly [7.11]. Tilly's paper comes from the activities of a European network CONREPNET, which has examined well over 100 case studies in some detail and, apart from providing field data, has forced on developing criteria to permit alterative options to be evaluated to a common base. This information will also be used extensively later in this chapter.Repair and renovation is a huge subject, deserving several books in its own right.This book is about assessment, management and maintenance, and repair is an integral part of that. The emphasis in this chapter is on how it fits into the overall scheme of things, in moving forward from the assessment phase to taking effective action in selecting optimum solutions. This approach leads to the following sequence of subsection.7.2 Performance requirements for repaired structures7.3 Classification of protection, repair,renovation and upgrading options7.4 Performance requirements for repair and remedial measures7.5 Engineering specifications7.6 Moving towards the selection process7.7 Performance of repairs in sevice7.8 Timing of an intervention7.9 Selection a repair option-general7.10 The role of EN 1504 in selection7.11 Selecting a repair option in practice7.12 Concluding remarks Appendix 7.1 and 7.2 Reference7.2 Performance requirements for repaired structuresIn simple terms, the performance requirements for repaired structures are no different from those for new construction. Structurally, the focus will be on the factors listed in Table 4.12. Progressive assessment will have led to a performance time graph, such as that in Figure 3.13, for all relevant Table 4.12 factors. This paints a picture of how the present condition relates both to the performance levels provided in the original design and to the owner's perception of what constitutes minimum acceptable performance, bearing in mind that much more is now known about the structure (the Table 6.2 issue).Complicating the situation is the fact different owners may wish to manage the rehabilitation process differently. Figure 3.3 shows two viable options emanating from the asset management procedures associated with bridge in the UK . The different strategies involved intervention on different timescales, and,most probably, different solutions. Some owners may also wish to take a conservative approach,involving early preventative measures. There are no definitive general rules here, but a need to be aware of what the options are , linked to confidence in their effectiveness.In moving forward, however, it is essential to be clear about the required performance levels. While the basic structural factors in Table 4.12 will remain, there are broader strategies issues involved, some non-technical,which will influence the course which individual owners may choose to follow. Different owners will have different strategic goals, depending, for example, on:•type of ownership – whether private or public sector;•changing statutory requirements;•the type of structure and its function;•future plans for the structure, independent of its current physicall state, due, say, to – a possible change in use;-- improved performance requirements arising from higher user expectations;-- increases in imposed loadings;• a greater emphasis on whole life costing, linked to budgetary plans;•s desire for improved sustainability.In a follow-up project to CONTECVET, a group of parters containing a high proportion of owners from Spain, Sweden and the UK, set out to establish a strategy for the maitenance and rehabilition of concrete structures. As part of this project, acronym REHABCON, a list of general performance requirements was developed. Table 7.1, taken from a REHABCON deliverable [7.12] ,givesdetails. While the majority of the requirements relate to the structure as a whole, some also relate to the selected rehabilitation option and to the renovation process itself.Table 7.1 General performance requirements for rehabilitated structures.Rehabcon [7.12]General performance requirements__________________________________________________________________ Structural safety Ultimate limit state design (same expectations as for newstructures)•Strength•Stability•Robustness•Fatigue•Fire resistance•Earthquake resistanceServiceability Serviceability limit state design (same expectations as fornew structures)•Deformation•Displacement•Vibrations•Watertightness•Slip resistance/roughness•Drainage•Visibility during inclement weather•Comfort/convenience to userOperation and function•Availability, functionability•Minimisation of downtime. While this is important for a rehabilitated structure, it is also important to minimise inconvenience to users during the rehabilitation action,i.e,low low impact on users during operation, maintenance and repair.Aesthetics•Inspectability•Colour•Texture of surface•Durability of aesthetics•Safe-lookingSustainabilityand environmentalfactors•Materials for rehabilitation works tobe sustainable, and environmentally friendlyduring•Manufacture•Construction works•Use•Damage•Demolition•Impact on recycling and reuse•Deposition•Acoustics, noise control•Energy consumption•Harmful effects, such as spillage, leakage, dust or the emission of toxic fumes, either spontaneously or due to situiations such as fire, both duringthe rehabilitation works and afterwardsHeath andSafety•Public safety•Health for humans and nature during all phases in the life-cycle•Evacuation, emergency escape routesDurability•Durability of the original structure and the rehabilitated parts of the structure. Dependability•Reliability of the repair methods•Maitainability•Maintenance supportabilityFlexibility•Ensure that it is possible to meet future requirementEconomy•Reduce or limit whole life costs•Operational costs•Maintenance, repair and rehabilitation costs•Improvement/strengthening costs•Demolition and deposition costs•User cost•Limit loss of income due to insufficient functionality etc Cultureheritage•Structure having cultural or historic value require special treatment保护，预防，修复，改造和升级（摘自《混凝土结构腐蚀恶化的管理》第7章作者乔治·萨默维尔）7.1简介混凝土结构需要修复对我们来说并不陌生。
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。
The durability of concrete 英文版混凝土论文
The durability of concreteIn civil engineering, concrete is the most widely used and the amount of one of the largest building materials. Over the past century, the concrete strength to continuously improve its main development trends. China's large population, the urgent need for housing.Structural Design not only to meet the requirements of safe and reliable indicators, but also consider the durability requirements.The durability of concrete issues, refers to the structure in the environment and cause long-term evolution of the structure due to internal or external reasons, the concrete has to lose the ability to use. That for durability failure, the durability of many reasons, have antifreeze failure, failure of alkali - aggregate reaction, chemical corrosion failure. Part of the concrete structure in the environment below freezing, water in the pores will freeze, resulting in volume expansion of cold water migration, the formation of various pressures, when the pressure reaches a certain level, resulting in the destruction of the concrete.Alkali - aggregate reaction of concrete chemical reactions that occur by the active component of the alkali in the concrete aggregates, causing the expansion of the concrete, cracking, or even destroy. Response factors in the concrete, and its harmful effects are often not the root of the rule is a big hidden in the concrete works. Concrete structures in aggressive media environment, will cause the cement paste to a series of chemical, physical, and materialized change gradually been eroded, cement strength to reduce serious, as well as destruction. In concrete engineering in order to meet the requirements of concrete construction work, that is, water consumption, water-cement ratio is high, resulting in high porosity of the concrete, durability reduce. Also, the lack of hydrate stability in the cement paste will have an impact on the durability.Therefore, to improve the durability of concrete, must reduce the porosity of the concrete, especially the capillary porosity, the most important method is to reduce the concrete mixing water. But if we simply reduce the amount of water, the concrete decreases, will lead to tamping forming a total of difficulties, the same result in the concrete structure is not dense, and even cellular and macroscopic defects such as, not only reduce the strength of concrete, and the durability of concrete also reduced. To improve the durability of concrete basic There are several ways: First, the strength of the material and engineering properties of cement cement is hardening formed by the condensation of the cement mortar, cement paste, once damaged, the durability of concrete is damaged, the choice of cement should pay attention to the specific performance of the varieties of cement, select alkali content, low heat of hydration, shrinkage of a small, heat resistance, water resistance, corrosion resistance, good frost resistance of cement and in the circumstances to choose . The strength of cement is not the sole criterion to determine the concrete strength and performance, such as lower grade cement can also be the preparation of high-grade concrete. Therefore, the project select the strength of cement at the same time, the need to consider the engineering performance, and sometimes, its engineering performance is more important than the strength. Aggregates and admixtures choice of the aggregate consideration should be given its alkali activity to prevent the harm caused by alkali-aggregate reaction, corrosion resistance and water absorption of the aggregate, reasonable choice of gradation, to improve the workability of the concrete mixture to increase concrete density; a large number of studies have shown that the doped fly ash, slag, silica fume, etc. the mixed caineng effectively improve the performance of the concrete, to improve the pore structure of concrete, filling the internal voids, and to increase the density, high-ash concrete can inhibition of alkali-aggregate reaction, and thus doped hybrid materials of concrete, is to improve the durability of concrete and effective measures. Development in recent years, high-performance concrete. Second, the rational design of concrete mix mix design meet the concrete strength, work should be considered to minimize the amount of cement and water consumption, lower heat of hydration, reduce shrinkage cracks, and to increase the density, and reasonable water reducer and air entraining agent, to improve the internal structure of concrete, mixed with a sufficient amount of mixture to improve concrete durability. Structural members shall use the environmental design of the concrete cover thickness, to prevent the outside media to penetrate the internal corrosion of reinforced. Node structural design of the structure should also be considered a component to the overallendurance capacity after partial damage. The structural design shall also control the crack width of concrete cracks. Third, the incorporation of an appropriate amount of admixtures, water-reducing agent such as: liquidity needed to ensure that concrete mixture at the same time, minimizing water consumption, reduce water-cement ratio, so that the total porosity of the concrete, in particular, the capillary porosity substantially reduced. 4, the incorporation of the hydrate stability, lack of efficient activity of mineral admixtures: ordinary Portland cement concrete, cement paste is another major factor in the concrete can not be super durable.To eliminate the structure of the concrete itself disruptive factor: In addition to concrete structural damage caused by environmental factors, some of the concrete itself, physical and chemical factors may also cause serious damage of the concrete structure, resulting in concrete failure. To ensure the strength of concrete: strength and durability is a different concept, but is closely related to the nature of links between them is based on the internal structure of the concrete with water-cement ratio, this factor is directly related.Concrete construction should also consider the durability of concrete mixing and maximize the use of the second mixing method, wrap the sand method, wrapped in the process of gravel law, improve the workability of the concrete mixing materials, water retention and improve the concrete strength, reduce water consumption; pouring mass concrete vibrators shall control the temperature of concrete cracks, shrinkage cracks, construction cracks, concrete pouring and vibrating system, to improve concrete density and impermeability, attention to the process of the surface after the concrete vibratorsand enhance the conservation, in order to reduce the concrete cracks. Concrete construction process control component appearance of cracks, construction cracks is essential and should strengthen the construction quality management, the special season of construction of concrete structures, there should be to take special measures.So, we want to develop the new concrete, such as high performance concrete.Therefore, to improve the durability of concrete is the inevitable trend of development of the concrete.。
预应力混凝土Prestressed-Concrete大学毕业论文外文文献翻译及原文
毕业设计（论文）外文文献翻译文献、资料中文题目：预应力混凝土文献、资料英文题目：Prestressed Concrete文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：班级：姓名：学号：指导教师：翻译日期： 2017.02.14毕业设计（论文）外文资料翻译外文出处：The Concrete structure附件：1、外文原文；2、外文资料翻译译文。
1、外文资料原文Prestressed ConcreteConcrete is strong in compression, but weak in tension: Its tensile strength varies from 8 to 14 percent of its compressive strength. Due tosuch a Iow tensile capacity, fiexural cracks develop at early stages ofloading. In order to reduce or prevent such cracks from developing, aconcentric or eccentric force is imposed in the longitudinal direction of the structural element. This force prevents the cracks from developing by eliminating or considerably reducing the tensile stresses at thecritical midspan and support sections at service load, thereby raising the bending, shear, and torsional capacities of the sections. The sections are then able to behave elastically, and almost the full capacity of the concrete in compression can be efficiently utilized across the entire depth of the concrete sections when all loads act on the structure.Such an imposed longitudinal force is called a prestressing force,i.e., a compressive force that prestresses the sections along the span ofthe structural elementprior to the application of the transverse gravitydead and live loads or transient horizontal live loads. The type ofprestressing force involved, together with its magnitude, are determined mainly on the basis of the type of system to be constructed and the span length and slenderness desired.~ Since the prestressing force is applied longitudinally along or parallel to the axis of the member, the prestressing principle involved is commonly known as linear prestressing.Circular prestressing, used in liquid containment tanks, pipes,and pressure reactor vessels, essentially follows the same basic principles as does linear prestressing. The circumferential hoop, or "hugging" stress on the cylindrical or spherical structure, neutralizes the tensile stresses at the outer fibers of the curvilinear surface caused by the internal contained pressure.Figure 1.2.1 illustrates, in a basic fashion, the prestressing action in both types of structural systems and the resulting stress response. In(a), the individual concrete blocks act together as a beam due to the large compressive prestressing force P. Although it might appear that the blocks will slip and vertically simulate shear slip failure, in fact they will not because of the longitudinal force P. Similarly, the wooden staves in (c) might appear to be capable of separating as a result of the high internal radial pressure exerted on them. But again, because of the compressive prestress imposed by the metal bands as a form of circular prestressing, they will remain in place.From the preceding discussion, it is plain that permanent stresses in the prestressed structural member are created before the full dead and live loads are applied in order to eliminate or considerably reduce the net tensile stresses caused by these loads. With reinforced concrete,it is assumed that the tensile strength of the concrete is negligible and disregarded. This is because the tensile forces resulting from the bending moments are resisted bythe bond created in the reinforcement process. Cracking and deflection are therefore essentially irrecoverable in reinforced concrete once the member has reached its limit state at service load.The reinforcement in the reinforced concrete member does not exert any force of its own on the member, contrary to the action of prestressing steel. The steel required to produce the prestressing force in the prestressed member actively preloads the member, permitting a relatively high controlled recovery of cracking and deflection. Once the flexural tensile strength of the concrete is exceeded, the prestressed member starts to act like a reinforced concrete element.Prestressed members are shallower in depth than their reinforced concrete counterparts for the same span and loading conditions. In general, the depth of a prestressed concrete member is usually about 65 to 80 percent of the depth of the equivalent reinforced concrete member. Hence, the prestressed member requires less concrete, and,about 20 to 35 percent of the amount of reinforcement. Unfortunately, this saving in material weight is balanced by the higher cost of the higher quality materials needed in prestressing. Also, regardless of the system used, prestressing operations themselves result in an added cost: Formwork is more complex, since the geometry of prestressed sections is usually composed of. flanged sections with thin-webs.In spite of these additional costs, if a large enough number of precast units are manufactured, the difference between at least the initial costs of prestressed and reinforced concrete systems is usually not very large.~ And the indirect long-term savings are quite substantial, because less maintenance is needed; a longer working life is possible due to better quality control of the concrete, and lighter foundations are achieved due to the smaller cumulative weight of the superstructure.Once the beam span of reinforced concrete exceeds 70 to 90 feet (21.3 to 27.4m), the dead weight of the beam becomes excessive, resulting in heavier members and, consequently, greater long-term deflection and cracking. Thus, for larger spans, prestressed concrete becomes mandatory since arches are expensive to construct and do not perform as well due to the severe long-term shrinkage and creep they undergo.~ Very large spans such as segmental bridges or cable-stayed bridges can only be constructed through the use of prestressing.Prestressd concrete is not a new concept, dating back to 1872, when P. H. Jackson, an engineer from California, patented a prestressing system that used a tie rod to construct beams or arches from individual blocks [see Figure 1.2.1 (a)]. After a long lapse of time during which little progress was made because of the unavailability of high-strength steel to overcome prestress losses, R. E. Dill of Alexandria, Nebraska, recognized the effect of the shrinkage and creep (transverse material flow) of concrete on the loss of prestress. He subsequently developed the idea that successive post-tensioning of unbonded rods would compensate for the time-dependent loss of stress in the rods due to the decrease in the length of the member because of creep and shrinkage. In the early 1920s,W. H. Hewett of Minneapolis developed the principles of circular prestressing. He hoop-stressed horizontal reinforcement around walls of concrete tanks through the use of turnbuckles to prevent cracking due to internalliquid pressure, thereby achieving watertightness. Thereafter, prestressing of tanks and pipes developed at an accelerated pace in the United States, with thousands of tanks for water, liquid, and gas storage built and much mileage of prestressed pressure pipe laid in the two to three decades that followed.Linear prestressing continued to develop in Europe and in France, in particular through the ingenuity of Eugene Freyssinet, who proposed in 1926--1928 methods to overcome prestress losses through the use of high-strength and high-ductility steels. In 1940, he introduced thenow well-known and well-accepted Freyssinet system.P. W. Abeles of England introduced and developed the concept of partial prestressing between the 1930s and 1960s. F. Leonhardt of Germany, V. Mikhailov of Russia, and T. Y. Lin of the United States also contributed a great deal to the art and science of the design of prestressed concrete. Lin's load-balancing method deserves particular mention in this regard, as it considerably simplified the design process, particularly in continuous structures. These twentieth-century developments have led to the extensive use of prestressing throughoutthe world, and in the United States in particular.Today, prestressed concrete is used in buildings, underground structures, TV towers, floating storage and offshore structures, power stations, nuclear reactor vessels, and numerous types of bridge systems including segn~ental and cable-stayed bridges, they demonstrate the versatility of the prestressing concept and its all-encompassing application. The success in the development and construction of all these structures has been due in no small measures to the advances in the technology of materials, particularly prestressing steel, and the accumulated knowledge in estimating the short-and long-term losses in the prestressing forces.~2、外文资料翻译译文预应力混凝土混凝土的力学特性是抗压不抗拉：它的抗拉强度是抗压强度的8％一14％。
混凝土的英文作文
混凝土的英文作文英文：Concrete is a versatile and durable building material that is widely used in construction. It is composed of a mixture of cement, water, and aggregates, such as sand, gravel, or crushed stone. The mixture is then poured into molds or forms and allowed to harden and cure.One of the key benefits of concrete is its strength and durability. It can withstand heavy loads and harsh weather conditions, making it ideal for use in foundations, walls, and floors. Additionally, concrete is fire-resistant and can help to prevent the spread of flames in the event of a fire.Another advantage of concrete is its versatility. It can be molded into various shapes and sizes, allowing for a wide range of design possibilities. It can also be colored or textured to create a unique look and feel.However, there are some drawbacks to using concrete. It can be expensive and time-consuming to install, and it is not always the most environmentally friendly option. Additionally, concrete can crack and deteriorate over time, requiring maintenance and repair.Overall, concrete is a reliable and durable building material that has been used for centuries. With proper installation and maintenance, it can last for many yearsand provide a solid foundation for any structure.中文：混凝土是一种多功能且耐用的建筑材料，在建筑中被广泛使用。
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.。
毕业论文外文翻译-混凝土的耐久性
Durability of concreteBesides its ability to sustain loads, concrete is also required to be durable .The durability of concrete can be defined as its resistance to deterioration resulting from external and internal causes. The external causes include the effects of environmental and service conditions to which concrete is subjected, such as weathering, particularly chlorides and sulphates, in the constituent materials, interaction between the constituent materials, such as alkali-aggregate reaction, volume changes, absorption and permeability.In order to produce a durable concrete, care should be taken to select suitable constituent materials. It is also important that mix contains adequate quantities of materials in proportions suitable for producing a homogeneous and fully compacted concrete mass.WeatheringDeterioration of concrete by weathering is usually brought about by the disruptive action of alternate freezing and thawing of free water within the concrete and expansion and contraction of the concrete, under restraint, resulting from variations in temperature and alternate wetting and drying.Damage to concrete from freezing and thawing arises from the expansion of pore water during freezing; in a condition of restraint, if repeated a sufficient number of times, this results in the development of hydraulic pressure capable of disrupting concrete. Road Krebs and slabs, dams and reservoirs are very susceptible are very susceptible to frost action.The resistance of concrete to freezing and thawing can be improved by increasing its impermeability. This can be achieved by using a mix with the lowest possible water-cement ratio compatible with sufficient workability for placing and compacting into a homogeneous mass. Durability can be further improved by using air entrainment, an air content of 3 to 6 per cent of the volume of concrete normally being adequate for most applications. The use of air entrained concrete is particularly useful for roads where salts are used for deicing.Chemical Attackin general, concrete has a low resistance to chemical attack.There are several chemical agents which react with concrete but the most common forms of attack are those associated with leaching, carbonation, chlorides and sulphates. Chemical agents essentially react with certain compounds of the hardened cement paste and the resistance of concrete to chemical attack therefore can be affected by the type of cement used. The resistance to chemical attack improves with increased impermeability.WearThe main causes of wear of concrete are the cavitation effects of fast-moving water, abrasive material in water, wind blasting and attrition and impact of traffic. Certain conditions of hydraulic flow result in the formation of cavities between the flowing water and the concrete surface .These cavities are usually filled with water vapor charged with extraordinarily high energy and repeated contact with the concrete surface results in the formation of pits and holes, Known an cavitation erosion. Since even a good-quality concrete will not be able to resist this kind of deterioration, the best remedy is therefore the elimination of cavitation by producing smooth hydraulic flow. Wherenecessary, the critical areas may be lined with materials having greater resistance to cavitation erosion.In general, the resistance of concrete to erosion and abrasion increases with increase in strength. The use of a hard and tough aggregate tends to improve concrete resistance to wear.Alkali-Aggregate ReactionsCertain natural aggregates react chemically with the alkalis present in Portland cement. When this happens these aggregates expand or swell resulting in cracking and disintegration of concrete.Volume ChangesPrincipal factors responsible for volume changes are the chemical combination of water and cement and the subsequent drying of concrete, variations in temperature and alternate wetting and drying. When a change in volume is resisted by internal or external forces this can produce cracking, The greater the imposed restraint, the more severe the cracking. The presence of cracks in concrete reduces its resistance to the action of leaching, corrosion of reinforcement, attack by sulphates and other chemicals, alkali-aggregate reaction and freezing and thawing, all of which may lead to disruption of concrete. Severe cracking can lead to complete disintegration of the concrete surface particularly when this is accompanied by alternate expansion and contraction.V olume changes can be minimized by using suitable constituent materials and mix proportions having due regard to the size of structure. Adequate moist curing is also essential to minimize the effects of any volume changes.Permeability and AbsorptionPermeability refers to the ease with which water can pass through the concrete. This should not be confused with the absorption property of concrete and the two are not necessarily related. Absorption may be defined as the ability of concrete to draw water into its voids. Low permeability is an important requirement for hydraulic structures and in some cases water tightness of concrete may be considered to be more significant than strength although, other conditions being equal, concrete of low permeability will also be strong and durable. A concrete which readily absorbs water is susceptible to deterioration. Concrete is inherently a porous material. This arises from the use of water in excess of that required for the purpose of hydration in order to make the mix sufficiently workable and the difficulty of completely removing all the air from the concrete during compaction. If the voids are interconnected concrete becomes pervious although with normal care concrete is sufficiently impermeable for most purposes. Concrete of low permeability can be obtained by suitable selection of its constituent materials and their proportions followed by careful placing, compaction and curing. In general for a fully compacted concrete, the permeability decreases with decreasing water-cement ratio. Permeability is affected by both the fineness and the chemical composition of cement. Aggregates of low porosity are preferable when concrete with a low permeability is required. Segregation of the constituent materials during placing can adversely affect the impermeability of concrete.混凝土的耐久性混凝土除了承受荷载之外，还需要有一定的耐久性。
土木工程专业钢筋混凝土结构设计毕业论文外文文献翻译及原文
毕业设计（论文）外文文献翻译文献、资料中文题目：钢筋混凝土结构设计文献、资料英文题目：DESIGN OF REINFORCED CONCRETE STRUCTURES 文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：土木工程班级：姓名：学号：指导教师：翻译日期： 2017.02.14毕业设计（论文）外文参考资料及译文译文题目：DESIGN OF REINFORCED CONCRETE STRUCTURES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 thestress of steel bars will increase . When the steel approaches the yielding stress ƒy , thedeflection 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 cross sections .As concrete has high modulus of elasticity, reinforced concrete structures are usuallystiffer 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.(b)Reinfoced concrete beam(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 are cheaper.(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 reinforcedconcrete 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 prestressed concrete 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。
建筑施工混凝土裂缝 毕业论文外文文献翻译
Building construction concrete crackAbstractThe crack problem of concrete is a widespread existence but again difficult in solve of engineering actual problem, this text carried on a study analysis to a little bit familiar crack problem in the concrete engineering. Keyword:Concrete crackForewordConcrete's ising 1 kind is anticipate by the freestone bone, cement, water and other mixture but formation of the in addition material of quality brittleness not and all material.Because the concrete construction transform with oneself, control etc. a series problem, harden model of in the concrete existence numerous tiny hole, spirit cave and tiny crack, is exactly because these beginning start blemish of existence just make the concrete present one some not and all the characteristic of quality.The tiny crack is a kind of harmless crack and accept concrete heavy, defend Shen and a little bit other use function not a creation to endanger.But after the concrete be subjected to lotus carry, difference in temperature etc. function, tiny crack would continuously of expand with connect, end formation we can see without the aid of instruments of macro view the crack be also the crack that the concrete often say in the engineering.Concrete crack creation of the reason be a lot of and have alreadytransformed 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 bigphysical 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.2.The Su constringency crack and preventionSu constringency is the concrete is before condense, surface because of lose water quicker but creation of constringency.The Su constringency crack is general at dry heat or strong wind the weather appear, crack's much presenting in the center breadth, both ends be in the centerthin and the length be different, with each other not coherent appearance.Shorter crack general long 20-30 cm, the longer crack can reach to a 2-3 m, breadth 1-5 mm.It creation of main reason is:The concrete is eventually almost having no strength or strength before the Ning very small, perhaps concrete just eventually Ning but strength very hour, be subjected to heat or compare strong wind dint of influence, the concrete surface lose water to lead quick, result in in the capillary creation bigger negative press but make a concrete physical volume sharply constringency, but at this time the strength of concrete again can't resist its constringency, thereforecreation cracked.The influence concrete Su constringency open the main factor of crack to have water ash ratio, concrete of condense time, environment temperature, wind velocity, relative humidity...etc..3.Sink to sink crack and preventionThe creation which sink to sink crack is because of the structure foundation soil quality not and evenly, loose soft or return to fill soil dishonest or soak in water but result in the asymmetry sink to decline with the result that;Perhaps because of template just degree shortage, the template propped up to once be apart from big or prop up bottom loose move etc. to cause, especially at winter, the template prop up at jelly soil up, jelly the soil turn jelly empress creation asymmetry to sink 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.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 areaof 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.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。
土木工程专业外语混凝土含翻译
4 Where fresh concrete is placed on hardened concrete, a good bond must be developed.5 The temperature of fresh concrete must be controlled from the time of mixing through final placement, and protected after placement.。
to avoid segregation.Selection of the most appropriate technique for economy depends on jobsite conditions, especially project size, equipment, and the contractor’s experience.In building construction，power-operated buggies; drop bottom buckets with a inclined chutes; flexible and rigid pipe by pumping;which either dry materials and water are sprayed separately or mixed concrete is shot against the forms; and for underwater placing, tremie chutes (closed flexible tubes).side-dump cars on narrow-gageFor pavement, concrete may be placed by bucket from the swinging boom of a paving mixer, directly by dump truck or mixer truck, or7 Even within the specified limits on slump and water-cementitious materials ratio, excess water must be avoided.In this context, excess water is presented for the conditions of placing if evidence of water rise (vertical segregation) or water flow (horizontal segregation) occurs.Excess water also tends to aggravate surface defects by increasedleakage through form openings. The result may be honeycomb, variations in color, or soft spots at the surface.8 In vertical formwork, water rise causes weak planes between each layer deposited. In addition to the deleterious structural effect, such planes, when hardened, contain voids which water may pass through.9 In horizontal elements, such as floor slabs, excess water rises and strength, low high and generallypoor quality.10 The purpose of consolidation is to eliminate voids of air and to ensure intimate complete contact of the concrete with the surfaces of the forms and the reinforcement.Intense vibration, however, may also reduce the volume of desirable entrained air; but this reduction can be compensated by adjustment of the mix proportions11 Powered internal vibrators are usually used to achieve consolidation. For thin slabs, however, high-quality, low-slump concrete can be effectively consolidated, without excess water, by mechanical surface vibrators.For precast elements in rigid external vibration is highly effective. External vibration is also effective with in-place forms, but should not be used unless the formwork is for theimpact of the vibrator.12 Except in certain paving operations, vibration of the reinforcement should be it is effective, thevertical rebars passing into partly set concrete below may be harmful.Note, however, that re-vibration of concrete before the final set, under controlled conditions, can improve concrete strength markedly and reduce surface voids.This technique is too difficult to control for general use on field-cast vertical elements, but it is very effective in finishing slabs with powered vibrating equipment.13 The interior of columns is usually congested; it contains a large volume of reinforcing steel compared with the volume of concrete, and has a large height compared with its cross-sectional dimensions.Therefore, though columns should be continuously cast, the concrete should be placed in 2-to 4-ft-deep increments and consolidated with internal vibrators. These should be lifted after each increment has been vibrated.If delay occurs in concrete supply before a beenWhen the remainder of the column isportion slightly.14 In all columns and reinforced narrow walls, concrete placing should begin with 2 to 4 inches of grout. Otherwise, loose stone will collect at the bottom, resulting in the formation of honeycomb. This grout should be proportioned for about the same slump as the concrete or slightly more, but at the same or lower water-cementitious material ratio.the same proportions of butWhen concrete is placed for walls,the only practicable means to avoid segregation is to place no more than a 24-in layer in one pass. Each layer should be vibrated separately and kept nearly level.15 For walls deeper than 4 ft, concrete should be placed through vertical. The concrete should not fall free more than 4 ft or segregation will occur, with the coarse aggregate ricocheting off thelayers after the initial layer should be penetrated by.can be beneficial (re-vibration), but control under variable jobsite conditions is too uncertain for recommendation of this practice for general use.16 The results of poor placement in walls are frequently observed:slope layer lines; honeycombs, leaking, if water is present; and, if cores are taken at successive heights, up to a 50% reduction in strength from bottom to top. Some precautions necessary to avoid these ill effects are:17 Do not move concrete laterally with vibrators18 For deep, long walls, reduce the slump for upper layers 2 to 3 in below the slump for the starting layer.19 On any placing of layers, vibrate the concrete20 Concrete should be inspected for the owner before, during, and after casting. Before concrete is placed, the formwork must be free of ice and debris and properly coated with bond-breaker oil.The rebars must be in place, properly supported to bear any traffic they will receive during concrete placing.inserts, and other items to be embedded must be inConstruction personnel should be available, usually carpenters, bar placers and other trades, if piping or electrical conduit is to be embedded, to act as form watchers and to reset any rebars, conduit, or piping displaced.21 As concrete is cast, the slump of the concrete must be observed and regulated within prescribed limits, or the specified strengths based on the expected slump may be reduced.An inspector of placing who is also responsible for sampling and making cylinders, should test slump, temperatures, and unit weights, during concreting and should control any field adjustmentThe inspector should also that handling, placing, and finishing procedures that agreed on in advance are properly followed, to avoid segregated concrete.should ensure that any construction joints made necessary by stoppage of concrete supply, rain, or other delays are properly located and made in accordancewith procedures specified or approved by the engineer.22 Inspection is complete only when concrete is cast, finished, protected for curing, and attains full strength.1混凝土适当放置的原则是：2在混合器和放置点之间的所有操作（包括最终固结和精整）期间必须避免分离。
土木工程专业Reinforced-Concrete钢筋混凝土大学毕业论文外文文献翻译及原文
毕业设计（论文）外文文献翻译文献、资料中文题目：钢筋混凝土文献、资料英文题目：Reinforced Concrete文献、资料来源： __________________________ 文献、资料发表（出版）日期： _____________________ 院（部）:专业：_________________________________________ 班级：_________________________________________ 姓名：_________________________________________ 学号：_________________________________________ 指导教师：翻译日期：2017.02.14外文文献翻译Reinforced ConcreteCon crete and rein forced con crete are used as build ing materials in every coun try. In many, in clud ing the Un ited States and Can ada, rein forced con crete is a dominant structural material in engin eered con structi on.The uni versal n ature of rein forced con crete con structi on stems from the wide availability of rei nforci ng bars and the con stitue nts of con crete, gravel, sand, and cement, the relatively simple skills required in con crete con structi on, and the economy of rein forced con crete compared to other forms of con structi on. Con crete and rein forced con crete are used in bridges, build ings of all sorts un dergro und structures, water tan ks, televisi on towers, offshore oil explorati on and product ion structures, dams, and eve n in ships.Rein forced con crete structures may be cast-i n-place con crete, con structed in their fin al locatio n, or they may be precast con crete produced in a factory and erected at the con structi on site. Con crete structures maybe severe and functional in design, or the shape and layout and be whimsical and artistic. Few other buildi ng materials off the architect and engin eer such versatility and scope.Con crete is stro ng in compressi on but weak in tension. As a result, cracks develop whe never loads, or restrai ned shri nkage of temperature changes, give rise to tensile stresses in excess of the tensile strengthof the con crete. In a pla in con crete beam, the mome nts about the n eutral axis due to applied loads are resisted by an internal tension-compression couple involving tension in the concrete. Such a beamfails very suddenly and completely when the first crack forms. In a reinforced concrete beam, steel bars are embedded in the con crete in such a way that the tension forces n eeded for mome nt equilibrium after the con crete cracks can be developed in the bars.The con structi on of a rein forced con crete member invo Ives build ing a from of mold in the shape of the member being built. The form must be strong eno ugh 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 duri ng the con cret ing operati on. After the con crete has harde ned, the forms are removed. As the forms are removed, props of shores are in stalled to support the weight of the con crete un til it has reached sufficie nt stre ngth to support the loadsby itself.The designer must proportion a concrete memberfor adequate strengthto resist the loads and adequate stiffness to prevent excessive deflecti ons. In beam must be proporti oned sothat it can be con structed.For example, the reinforcement must be detailed so that it can beassembled in the field, and since the con crete is placed in the form after the rei nforceme nt is inplace, the con crete must be ableto flow around,between, andpast 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 thearchitect of engineer early in the design, based on the followingcon siderati ons:1. Economy. Freque ntly, the foremost con sideratio n is the overall const of the structure. This is, of course, a fun cti on of the costs ofthe materials and the labor necessary to erect them. Frequently, however, the overall cost is affected as much or more by the overall con structi on time since the con tractor and owner must borrow or otherwise allocate money to carry out the con struct ion and will not receive a retur n on this investment until the building is ready for occupancy. In a typical large apartme nt of commercial project, the cost of con struct ion financing willbe a significant fraction of the total cost. As a result, financial savings due to rapid con structi on may more tha n offset in creased material costs. For this reas on, any measures the desig ner can take to sta ndardize the desig n and forming will gen erally pay off in reduced overall costs.In many cases the Ion g-term economy of the structure may be more importa nt tha n the first cost. As a result, maintenance and durability are importa nt con siderati on.2. Suitability of material for architectural and structural function.A rein forced con crete system freque ntly allows the desig ner to comb ine the architectural and structural functions. Con crete has the adva ntage that it is placed in a plastic con diti on and is give n the desired shapeand texture by meansof the forms and the finishing techniques. This allows such elements ad flat plates or other types of slabs to serve as load-bearingelements while providing the finished floor and / or ceiling surfaces. Similarly, rein forced con crete walls can providearchitecturally attractive surfaces in addition to having the ability to resist gravity, wind, or seismic loads. Fin ally, the choice of size of shape is governed by the designer and not by the availability of standard manu factured members.3. Fire resista nee. The structure in a buildi ng must withsta nd theeffects of a fire and rema in sta nding while the build ing is evacuated and the fire is exti nguished. A con crete buildi ng in here ntly has a 1- to 3-hour fire rat ing without special fireproofi ng or other details. Structural steel or timber build ings must be fireproofed to atta in similar fire ratin gs.4. Low maintenan ce. Con crete members in here ntly require less maintenance than do structural steel or timber members. This is particularly true if den se, air-e ntrained con crete has bee n used forsurfaces exposed to the atmosphere, and if care has bee n take n in the desig n to provide adequate drain age off and away from the structure. Special precauti ons must be take n for con crete exposed to salts such as deici ng chemicals.5. Availability of materials. Sand, gravel, ceme nt, and con cretemixi ng facilities are very widely available, and rein forci ng steel canbe tran sported to most job sites more easily tha n can structural steel. As a result, re in forced con crete is freque ntly used in remote areas.On the other hand, there are a nu mber of factors that may cause one to selecta material other tha n rein forced con crete. These in clude:1. Low tensile strength. The tensile strength concrete is much lower than its compressive strength ( about 1/10 ), and hence concrete is subject to crack ing. In structural uses this is overcome by using rei nforceme nt to carry ten sile forces and limit crack widths to with in acceptable values. Un less care is take n in desig n and con struct ion, however, these cracks maybe unsightly or mayallow penetration of water. Wherthis occurs, water or chemicals such as road deicing salts may cause deterioration or stai ning of the con crete. Special desig n details are required in such cases. In the case of water-retai ning structures, special details and /of prestress ing are required to preve nt leakage.2. Forms and shori ng. The con structi on of a cast-i n-place structureinvo Ives three steps not encoun tered in the con struct ion of steel or timberstructures. These are ( a ) the con struct ion of the forms, ( b ) the removal of these forms, and (c) propp ing or shori ng the new con crete to support its weight until itsstrength is adequate. Each of these steps invoIves labor and / or materials, which are not necessary with other forms of con structi on.3. Relatively low strength per unit of weight for volume. Thecompressive strength of concrete is roughly 5 to 10%that of steel, while its unit den sity is roughly 30% that of steel. As a result, a con cretestructure requires a larger volume and a greater weight of material than does acomparable steel structure. As a result, Iong-span structures are ofte n built from steel.4. Time-depe ndent volume cha nges. Both con crete and steelundergo-approximately the same amount of thermal expansionandcon tracti on. Because there is less mass of steel to be heated or cooled, andbecause steel is a better con crete, a steel structure is gen erallyaffected by temperature cha nges to a greater exte nt tha n is a con crete structure.On the other hand, con crete un dergoes fryi ng shri nkage, which, if restrained, may cause deflections or cracking. Furthermore, deflecti ons will tend to in crease with time, possibly doubli ng, due to creep of the con crete un der susta ined loads.In almost every branch of civil extensiveuse is made of reinforced foundations.Engineers and architects reinforced con crete desig n throughout theirprofessi onal careers. Muchof this text is directly concerned with the behavior and proporti oningof components that makeup typical reinforced concrete structures-beams, colu mns, and slabs. Once the behavior of these in dividual eleme nts is un derstood, the desig ner will have the backgro und to an alyze and desig n a wide range of complex structures, such as foun datio ns, buildi ngs, and bridges, composed of these eleme nts.Si nee rei nforced concrete is a no homogeneous material that creeps, shri nks,and cracks, its stresses cannot be accurately predicted by the traditi onal equati ons derived in a course in stre ngth of materials forhomoge neous elastic materials. Much of rein forced con crete desig n in thereforeempirical, i.e., design equations and design methods are based on experime ntal and engineering and architecture con crete for structures and requires basic knowledge oftime-proved results in stead of being derived exclusively from theoretical formulati ons.A thorough un dersta nding of the behavior of rein forced con crete will allow the desig ner to con vert an otherwise brittle material into tough ductile structural elements and thereby take advantage of concrete ' s desirable characteristics, its high compressive stre ngth, its fire resista nee, and its durability.Concrete, a stone like material, is madeby mixing cement, water, fine aggregate ( often sand ), coarse aggregate, and frequently other additives (that modify properties ) into a workable mixture. In its un harde ned or plastic state, concrete can be placed in forms to produce a large variety of structural eleme nts. Although the harde ned con crete by itself, i.e., without any rein forceme nt, is stro ng in compressi on, it lacks ten sile stre ngth and therefore cracks easily. Because unrein forced con crete is brittle, it cannot undergo large deformations under load and fails sudde nly-without warni ng. The additi on fo steel rein forceme nt to the con crete reduces the n egative effects of its two prin cipal in here nt weaknesses, its susceptibility to cracking and its brittleness. Whenthe rein forceme nt is stro ngly bon ded to the con crete, a strong, stiff, and ductile con struct ion material is produced. This material, calledrei nforced con crete, is used exte nsively to con struct foun dati ons,structural frames, storage takes, shell roofs, highways, walls, dams, canals, and innumerable other structures and building products. Twoother characteristics of concrete that are present even when concrete is rein forced are shri nkage and creep, but the n egative effects of these properties can be mitigated by careful desig n.A code is a set tech ni cal specificati ons and sta ndards that con trol importa nt details of desig n and con struct ion. The purpose of codes it produce structures so that the public will be protected from poor of in adequate and con struct ion.Two types f coeds exist. One type, called a structural code, is orig in ated and con trolled by specialists whoare concerned with the proper use of a specific material or who are invo Ived with the safe desig n of a particular class of structures.The sec ond type of code, called a build ing code, is established to cover con struct ion in a give n region, ofte n a city or a state. The objective of a build ing code is also to protect the public by acco un ti ng for the in flue nee of the local en vir onmen tal con diti ons on con structi on. For example, local authorities may specifyadditional provisions toaccount for such regional conditions as earthquake, heavy snow, ortorn ados. Nati onal structural codes gen rally are in corporated into local build ing codes.The America n Con crete In stitute ( ACI ) Buildi ng Code coveri ng the desig n of rein forced con crete build in gs. It contains provisi ons coveri ngall aspects of re in forced con crete manu facture, desig n, and con structi on. It includes specifications on quality of materials, details on mixing andplacing concrete, design assumptions for the analysis of continuous structures, and equati ons for proporti oning members for desig n forces.All structures must be proporti oned so they will not fail or deform excessively un der any possible con diti on of service. Therefore it is important that an engineer use great care in anticipating all the probable loads to which a structure will be subjected duri ng its lifetime.Although the desig n of most members is con trolled typically by dead and live load acting simultaneously, consideration must also be given tothe forces produced by wind, impact, shrinkage, temperature change, creep and support settleme nts, earthquake, and so forth.The load associated with the weight of the structure itself and its perma nent comp onents is called the dead load. The dead load of con crete members, which is substantial, should never be neglected in design computations. The exact magnitude of the dead load is not known accurately un til members have bee n 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 memberssized, 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 differenee 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 importa nt whe n spa ns are long, say over 75 ft ( 22.9 m ),because dead load con stitutes a major porti on of the desig n load.Live loads associated with building use are specific items of equipme nt and occupa nts in a certa in area of a build ing, buildi ng codes specify values of un iform live for which members are to be desig ned.After the structure has bee n sized for vertical load, it is checkedfor wi nd in comb in ati on with dead and live load as specified in the code. Windloads do not usually con trol the size of members in buildi ng lessthan 16 to 18 stories, but for tall buildings wind loads becomesignificant and cause large forces to develop in the structures. Under these conditions economycan be achieved only by selecting a structural system that is able to tran sfer horiz on tal loads into the ground efficie ntly.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。
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。
2021年最新混凝土搅拌站毕业论文外文翻译（完整版）
一.外文翻译CONCRETE MIXING PLANTThe apparatus of the present invention relates generally to concrete mixing plants and more specifically to such plants utilized to automatically and continuously mix separate concrete components into a wide range of predetermined quantities or batches.Conventional concrete plants and mixer trucks that can normally only be utilized for mixing single large batches of concrete. Such apparatus often are preset to mix a batch that is too large for a specific job. The remaining concrete must either be dumped or resold. If the remaining concrete is to be resold, it often must be watered down before it reaches the second job site.Conventional truck-mounted mixers are necessarily large in volume, to accommodate the labor cost of the individual driver. Furthermore, the concrete must be used within a fixed time span from its receipt in the truck. Delays in transit or unforeseen delay at the site of usage make it difficult to maintain a constant delivery schedule. Usually excess trucks and drivers must be used to assure a ready supply of concrete.Much greater control of concrete consistency and cost is possible by on-site mixing. However, conventional concrete mixers are designed for large scale batch mixing. The mixer described below fills the need for an on-site mixer readily adjustable to meet the instant demands of the user asto quantity and quality.A further problem is that with a premixed batch, it is difficult or impossible to make last minute adjustments in mixture proportions. This difficulty arises frequently in areas where quick climate changes are common and further, where specific building construction techniques call for different concrete stress characteristics.These problems are realized to a limited degree by the apparatus disclosed in U.S. Pat. Nos. 3,339,898 and 3,469,824 granted to Futtyetal. These patents disclosed mixing methods and mixing truck constructions where in concrete components are supplied to an elongated trough. An elongated shaft is provided within the trough having a plurality of spatially disposed mixing paddles and helical feeding screws. Rotation of the shaft simultaneously mixes the particulate ingredients and moves them toward an output end.U.S. Pat. No. 3,310,293 granted to Zimmerman discloses a concrete mixing and delivery system wherein concrete components are held within a plurality of bins supported on a truck frame. The components are held separately within the bins that provide means for dispensing predetermined amounts of the components onto an elongated conveyor belt. The conveyor delivers the separate components to an external mixing trough where water is applied to the dry components and they are mixed by an elongated auger within the mixing trough.Another patent granted to Futty, U.S. Pat. No. 3,336,011, discloses a system and means for selectively mixing concrete and incorporating additives therein which, like the Zimmerman apparatus, deposits concrete components onto a conveyor and delivers them separately to a mixing trough. Water is added to the components at the mixing trough as an auger is rotated to mix the components together. The principal feature of this invention is the provision of separate water supply systems in which either pure water or an antifreeze solution may be selectively applied to the mixture.A further patent granted to Futty, U.S. Pat. No. 3,623,708 discloses a system and means for selectively mixing concrete and incorporating dry additives therein. The apparatus includes means for delivering dry additives to the concrete batch and incorporates a hopper assembly for holding the dry additives. The hopper contains agitator means for mixing and breaking up the dry additive ingredients. A controlled feed means selectively controls the amount of dry additives passed from the hopper into an enclosed auger arrangement. The additives are conveyed by the auger arrangement into an auxiliary mixing trough where they are incorporated into a concrete batch. U.S. Pat. No. 2,976,025 granted to G. M. Pro discloses a combined mixer and conveyor for concrete components. Individual hoppers are used in the Pro apparatus for storing each concrete component. The apparatus includes means for deliveringsand and cement to a helical conveyor within a trough. The materials are received within the trough and tumbled and agitated as they are moved upwardly.Another U.S. Pat. No. 2,946,597, granted to M. W. Simonsen, discloses a fertilizer mixer and spreader with a partition container wherein fertilizer components are kept separately in longitudinally spaced bins. The bins include bottom openings through which the individual components are placed onto a conveyor and delivered to a fertilizer dispensing impeller. The fertilizer dropped onto the impeller is spread across the ground behind the supporting vehicle.U.S. Pat. No. 796,591 granted to W. B. Martin describes a concrete mixer in which individual concrete components are contained within separate hoppers. The apparatus includes means for removing measured amounts of gravel, stone, cement and sand in predetermined quantities and dropping them gravitationally downwardly into a mixing auger.It may be noted that each of the above-cited patents r elating to an apparatus f or mixing separate c oncrete components utilizes an auger or paddled wheel arrangement as means for mixing the components together. The apparatus of the present invention differs from this art in that the mixing of the components is accomplished by impact and shearing action. Mixing by impact is accomplished as the components are propelled against a stationary abutment surface, while mixing by shearing layers orstrata of the components is affected as the components are delivered from storage bins or fall from the abutment surface onto to second conveyor belt or other receiving conveyor.SUMMARY OF THE INVENTIONA concrete mixing plant is described comprising conveyor means for carrying concrete component mater als along a first direction of travel toa discharge point where they are propelled against an upright abutment surface. Supply means is also provided for placing controlled quantitiesof concrete component materials onto an upwardly facing surface of the conveyor means.It is a first object of my invention to provide a concrete mixing plant that is capable of producing a continuous supply of consistent wet concrete.Another object is to provide such a plant that may be controlled while in operation, to change mixture proportions and the consistency of the concrete produced.It is an additional object of my invention to provide such a concrete mixing plant that is relatively simple in3construction and therefore easy to operate. It can be transported to the job site or used as a central mixing plant.A yet further object is to provide such a mixing plant that includesseparate storage bins for each individual concrete component with a metering and discharge mechanism attached to each bin to facilitate control of the quantity of each individual component supplied to the mixture.These and further objects and advantages will become apparent upon reading the following disclosure which, taken with the accompanying drawings, discloses two preferred forms of the present invention.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a pictorial view of a first embodiment of the mixing plant;FIG. 2 is an enlarged elevational section view taken substantially along line 2—2 in FIG. 1;FIG. 3 is an enlarged elevational section view taken substantially along line 3—3 in FIG. 1;FIG. 4 is an enlarged elevational section view taken substantially along line 4—4 in FIG. 1;FIG. 5 is a fragmentary operational view taken substantially along line 5—5 in FIG. 1;FIG. 6 is a section view illustrating a weighing mechanism utilizedin conjunction with the present invention;FIG. 7 is a plan view of a slurry mixing mechanism incorporated inthe present invention;FIG. 8 is a cross sectional view taken substantially along line 8—8in FIG. 7;FIG. 9 is a plan view of a mixing plant mounted to a truck frame;FIG. 10 is an elevational view of the plant and truck as shown in FIG. 9;FIG. 11 is a sectioned view taken along line 11—11 in FIG. 9; andFIG. 12 is a fragmentary sectioned view taken along lines 12—12 in FIG. 9.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTSA first embodiment of the concrete mixing plant invention is illustrated in FIGS. 1 through 8 of the attached drawings and is generally designated therein by the reference numeral 10. A mixing plant 10 as shown, is supported by a framework 11. A plurality of component bins 12 and a dry cement bin 12a are located on the framework for receiving and storing individual concrete components such as sand, various size aggregate and, of course, dry cement.The component bins are elements of a supply means whereby the individual concrete components are placed in controlled layered quantities on an upwardly facing surface 13 of first and second conveyor means 14 and 26 respectively. In operation, the supply means is utilized to deliver dry concrete components to the first conveyor means 14 which in turn initially moves the components along a first direction of travel to adischarge end 15. The dry components fall from discharge end 15 ontothe second conveyor means 26. A wet cement slurry is added to the components as they move along on the second conveyor means 26 to a second discharge end 33. The components leave the discharge end 33 as a concrete mixture.混凝土搅拌站本发明的装置本发明一般涉及混凝土搅拌站，更具体地说，涉及这样的植物，利用自动连续到范围广泛的预定量或分批混合单独的混凝土构件。
毕业论文外文翻译-建筑施工混凝土开裂预防加工
毕业论文外文翻译-建筑施工混凝土开裂预防加工Prevention and Treatment of Concrete Cracks in Building ConstructionAbstract：Concrete is widely used in building construction because of its advantages such as durability, strength and low maintenance cost. However, concrete cracks can not only affect the aesthetic appearance of buildings, but also have negative impact on structural integrity and durability. This paper focuses on the prevention and treatment of concrete cracks in building construction. Firstly, the causes of concrete cracking are analyzed, including shrinkage, thermal stress, structural design, material quality and construction quality. Then, preventive measures in design and construction are proposed, such as proper reinforcement arrangement, control of concrete mix proportions, proper curing and protection after pouring, etc. Treatment measures for existing concrete cracks include surface treatment, filling and injection, and reinforcement. Finally, some new techniques are briefly introduced, such as fiber-reinforced concrete, self-healing concrete and material testing technology. This paper provides a comprehensive understanding of the prevention and treatment of concrete cracks in building construction, and proposes practical solutions to improve the quality of concrete structures.Key words: concrete cracks; building construction; prevention; treatmentIntroduction：Concrete is a popular building material due to its properties such as durability, strength and low maintenance cost. However, concrete cracking is a common problem in building construction, which can not only affect the aesthetic appearance of buildings, but also have negative impact on structural integrity and durability. Therefore, preventing and treating concrete cracks are crucial to ensure the long-term performance of buildings. This paper analyzes the causes of concrete cracking in building construction, and proposes preventive and treatment measures based on practical experience and research.1. Causes of Concrete Cracking：1.1 ShrinkageShrinkage is the most common cause of concrete cracking, which is due to the decrease in volume of concrete as it dries and hardens. Shrinkage can be classified into autogenous shrinkage, plastic shrinkage and drying shrinkage.Autogenous shrinkage is caused by the chemical reaction between water and cement, and it can lead to micro-cracks. Plastic shrinkage is caused by the evaporation of water from the surface of fresh concrete, which can cause cracks in the surface layer. Drying shrinkage is caused by the loss of moisture from the hardened concrete, which can lead to cracks in the bulk of the structure.1.2 Thermal StressThermal stress is another cause of concrete cracking, which is due to the temperature difference between the interior and exterior of concrete. When the temperature change is rapid or large, thermal stress can exceed the tensile strength of concrete and cause cracking.1.3 Structural DesignPoor structural design can also cause concrete cracking. For example, inadequate reinforcement or improper placement of reinforcement can lead to excessive stress concentration and cracking. In addition, insufficient structural support or improper joint design can also cause concrete cracking.1.4 Material QualityThe quality of concrete materials such as cement, aggregates and water can also affect concrete cracking. Poor quality materials can result in uneven shrinkage, low strength, and high water permeability, which can cause cracking.1.5 Construction QualityConstruction quality is an important factor in the prevention of concrete cracking. Improper placement, compaction and curing of concrete can lead to poor quality, which can cause cracking. In addition, inadequate protection measures such as insufficient cover or damage to the surface layer can also cause cracking.2. Prevention of Concrete Cracking：2.1 Reinforcement ArrangementProper reinforcement arrangement is essential to prevent concrete cracking. The size, spacing and distribution of reinforcement should be designed according to the structural requirements and the characteristics of concrete. In addition, the use of fiber reinforcement can improve the crack resistance of concrete.2.2 Control of Concrete Mix ProportionsThe control of concrete mix proportions is critical to the prevention of concrete cracking. The ratio of water to cement, the type and quality of aggregates, and the use of admixtures should be carefully considered to ensure proper workability and strength of concrete.2.3 Proper Curing and ProtectionProper curing and protection measures can effectively prevent concrete cracking. Adequate moist curing can reduce evaporation and shrinkage, and increase strength and durability. In addition, proper protection measures such as sufficient cover and protective coatings can protect the surface layer of concrete from damage.3. Treatment of Concrete Cracks：3.1 Surface TreatmentSurface treatment is a common method to repair concrete cracks. The damaged concrete is removed, and the surface is cleaned and roughened. Then, a bonding agent is applied and a new layer of concrete is poured to fill the crack.3.2 Filling and InjectionFilling and injection is another effective method to repair concrete cracks. The crack is filled with cementitious material, such as epoxy or polymer, to restore theintegrity of the structure. Injection is also used to repair cracks in reinforced concrete structures, where the material is injected under pressure to fill the voids and cracks.3.3 ReinforcementReinforcement is used when the crack is severe and structural integrity is compromised. Steel bars or plates are installed into the crack and bonded to the surrounding concrete to restore the strength and load-carrying capacity of the structure.4. New Techniques：4.1 Fiber-Reinforced ConcreteFiber-reinforced concrete is a new type of concrete that contains short fibers, such as glass, steel or synthetic fibers, which can improve the crack resistance and toughness of concrete.4.2 Self-Healing ConcreteSelf-healing concrete is a novel material that can repair micro-cracks by itself through the chemical reaction between water and the embedded capsules.4.3 Material Testing TechnologyMaterial testing technology such as acoustic emission and electrical resistance can effectively detect and monitor the formation and propagation of cracks in concrete structures, and provide early warning for potential failures.Conclusion：Concrete cracking is a common problem in building construction, which can affect the aesthetic appearance, structural integrity and durability of buildings. This paper analyzes the causes of concrete cracking, and proposes practical preventive and treatment measures to improve the quality of concrete structures. In addition, some new techniques such as fiber-reinforced concrete, self-healing concrete andmaterial testing technology are briefly introduced. With proper design, construction and maintenance, the occurrence and impact of concrete cracking can be effectively reduced, and the long-term performance of concrete structures can be ensured.。
土木工程专业混凝土结构配筋设计毕业论文外文文献翻译及原文
毕业设计（论文）外文文献翻译文献、资料中文题目：混凝土结构配筋设计文献、资料英文题目：Concrete structure reinforcement design 文献、资料来源：文献、资料发表（出版）日期：院（部）：专业：土木工程班级：姓名：学号：指导教师：翻译日期： 2017.02.14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 the main 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 not too high situation, increases the main reinforcement area to be possible to propose the plateau component right section anti-curved supporting capacity effectively. Is pulled in 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 with the 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 after reinforcing, 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 member reinforcement.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 similarmerit, 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, this fashion 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 。
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。
混凝土的英文作文
混凝土的英文作文英文：Concrete is a versatile and durable building material that has been used for centuries. It is made by mixing cement, water, and aggregates like sand, gravel, or crushed stone. The mixture is then poured into a form and allowed to harden, creating a solid structure that can withstand heavy loads and harsh weather conditions.One of the benefits of concrete is its strength. It has a high compressive strength, which means it can withstand a lot of weight without breaking or cracking. This makes it an ideal material for building foundations, bridges, and other structures that need to support heavy loads.Another advantage of concrete is its durability. It can last for decades or even centuries without needing significant repairs or maintenance. This is especially true if it is reinforced with steel bars, which can help preventcracking and other forms of damage.Concrete is also a versatile material that can be molded into different shapes and sizes. This makes it suitable for a wide range of applications, from building walls and floors to creating decorative features like statues and fountains.Overall, concrete is a reliable and cost-effective building material that has stood the test of time. Whether you're constructing a new home or building a massive infrastructure project, it's worth considering as a viable option.中文：混凝土是一种多功能且耐用的建筑材料，已经使用了几个世纪。
外文资料翻译——混凝土结构的耐久性
中文2915字毕业设计外文资料翻译（一）外文出处：Jules Houde 《Sustainable development slowed downby bad construction practices and natural and technological disasters》1、外文原文（复印件）毕业设计外文资料翻译（二）外文出处：Jules Houde 《Sustainable development slowed down by bad construction practices and natural and technological disasters》2、外文资料翻译译文混凝土结构的耐久性即使是工程师认为的最耐久和最合理的混凝土材料，在一定的条件下，混凝土也会由于开裂、钢筋锈蚀、化学侵蚀等一系列不利因素的影响而易受伤害。
近年来报道了各种关于混凝土结构耐久性不合格的例子。
尤其令人震惊的是混凝土的结构过早恶化的迹象越来越多。
每年为了维护混凝土的耐久性，其成本不断增加。
根据最近在国内和国际中的调查揭示，这些成本在八十年代间翻了一番，并将会在九十年代变成三倍。
越来越多的混凝土结构耐久性不合格的案例使从事混凝土行业的商家措手不及。
混凝土结构不仅代表了社会的巨大投资，也代表了如果耐久性问题不及时解决可能遇到的成本，更代表着，混凝土作为主要建筑材料，其耐久性问题可能导致的全球不公平竞争以及行业信誉等等问题。
因此，国际混凝土行业受到了强烈要求制定和实施合理的措施以解决当前耐久性问题的双重的挑战，即：找到有效措施来解决现有结构剩余寿命过早恶化的威胁。
纳入新的结构知识、经验和新的研究结果，以便监测结构耐久性，从而确保未来混凝土结构所需的服务性能。
所有参与规划、设计和施工过程的人，应该具有获得对可能恶化的过程和决定性影响参数的最低理解的可能性。
这种基本知识能力是要在正确的时间做出正确的决定，以确保混凝土结构耐久性要求的前提。