建筑施工混凝土裂缝的预防与处理外文翻译

现浇楼板裂缝防治外文翻译文献(文档含中英文对照即英文原文和中文翻译) roduction and prevention and cure of the crack of skyscraperAlong with the speeding of town house construction step, not a few areas with small residences set up one after another, many inhabitants move continuously into the new residence, their quality to housing request is more and more high, particularly pay attention to very much to some cracks circumstances which sprinkle building plank to appear now, worry these cracks' aring end will cause insecurity trouble, but in succession to building quality direct the section hurl tell.Such as once the some city develop a company to set up 6 layers of floorresidence 16 totally, constructing area about 100,000 square meters, the brick mixs structure, the beginning repairs, one steps 2 box off with the brick wall, each one's establishing a turn of beam together building plank is togetherwhole to sprinkle, the plank thick 100 mms, concrete mark number is C20, house long about with 80-90 ms, don't establish flexible sew, first floor is the 2.2 m garage layer, the C20 reinforcing bar cage of the foundation adoption infuses to note a stake.It's small area's turn to complete work in October,2003, finishing construction acceptance, didn't discover obvious crack, discover the building plank appears crack when the inhabitant repair, past jointly to quality direct the section hurl tell, through step to see on the spot, 16 houses all exist the depth different crack.The crack width is between the 0.2 mms mms-0.4ses, the great majority of the crack position is placed in plank four Capes, the dynasty sun is more obvious.Hence, the Superintendent office of quality concerned, sinking to decline quantity and inclination degree to carry on a reexamination to the house first, result all in allow the scope, again look into construction diagram paper to also match to request concerning the norm.Owing to above-mentioned circumstance, pass by hard analytical, the confirmation crack reason has the following what time:1. cause now main reason of sprinkling the plank crack is the constringency of concrete, the concrete is in the nature the hardening the process, because water evaporates continuously, but the physical volume gradual constringency, but the plank is on all sides to be subjected to a stipulation of, can't flex freely,so when the constringency of concrete cause to sprinkle knothole stipulation now should the dint exceed certain limit, certanly will cause to sprinkle plank to open crack now.And the crack part take place much at should the dint more concentrated Cape in the place-plank, but is mutually perpendicular with the Overcast angle line of wall2. construct too early on the cast-in-place board , add and carry on one's shoulder or back the crack caused. " norm of inspection of quality of structural construction of concrete " stipulates , before the concrete intensity reaches 1.2N/mm2, can't trample or install template and support on it . But developer , for race against time , catch up with progress , or concrete at , congeal and congeal stage after all for the first time still in water at the good cast-in-place board just, take up the post of purpose to trample, carry the material , concentrate on piling up fragment of brick , mortar , template ,etc.. Premature adding and is carried on one's shoulder or back, has caused the crack of cast-in-place board artificially.3. the crack which the temperature change causes. As everybody knows, the cement condenses and hardens fast at room temperature, the characteristic such as being great of heat of hydration, especially in summer, after the concrete is built, the release amount of the heat of hydration is great, the concrete is under the high temperature, can't get and water maintenance in time , and desiccate and shrink, make concrete take place dry to split , result in fracturing finally. Investigation find in the majority board corner crack in , tan by the sun towardsthe front directly the sun.4.the house is crossed too long to set up the essential expansion joint , is the reason which causes the crack too. The developer is in order to save the land, often take the length of the house into account , make the house whole too long, set up expansion joint either, because of lack essential expansion joint, freedom flexible degree in house reach or exceed should set up interval that expansion joint require , will present the crack too.5.the board is defeated by the muscle and sunk in the crack produced . In the course of constructing, because constructors operate barbarously, trample the reinforcing bar arbitrarily , cause and shoulder the muscle and sink, the antiabrasion layer is too big, reduce the sectional effective height of the board, make the bearing capacity of the board unable to reach the requirement of ones that design, thus cause the production of the crack of board.Effective height, make the bearing capacity of the board unable to reach the requirement of ones that design, thus cause the production of the crack of board. How to prevent and cure the production of the board crack of cast-in-place board, according to the construction experience for many years, offer some following prevention measures, suitable for consulting :1. Do well cast-in-place board maintain , work , guarantee concrete intensity , prevent and cure important link that crack produce one of conscientiously. The norm stipulates , must cover and keep maintenance warm in 12 hours after the concrete is built at room temperature, ordinary cement is noless than 7 days, if the one that ignored to concrete watered maintenance, on one hand it reduce concrete intensity, on the other hand it make concrete to be in the course of hardening too late to supplement the moisture, therefore lack water and produce the crack in a large amount. So do a good job of watering maintenance of concrete , can already reduce the crack that temperature produces , can also reduce the crack that the concrete shrink and produce .2. cast-in-place board don't pass morning people , pile material , He Shi load , because concrete have a sclerosis course build ,, just have intensity; In this course , should maintain the concrete , can't exert any external force to the concrete . In a situation that the concrete has not had certain intensity yet , concentrate on , pile up construction material or prop up mould stand , rest on it, that brought the cast-in-place board is not intensity like this, but more cracks. So, must make sure that just allow to trample or install template and support on it after the concrete intensity reaches 1.2N/mm2.3. shoulder thickness of antiabrasion layer of the muscle the strict control panel . Cast-in-place board shoulder muscle put , on board , have roof beam according to designing requirement through generally put on reinforcing bar of roof beam or stay with reinforcing bar lashing of roof beam cut off , For control good to shoulder muscle antiabrasion layer thickness , must adopt φ10 - φ14 reinforcing bar horse stool, vertical-horizontal interval 800mm come fixed position to shoulder muscle from side to side, and with electric welding horse with shoulder muscle weld firm stool, make horse to be stool while the concretebuilds non-wiping, guarantee , shoulder muscle sink, control , shoulder muscle thickness of antiabrasion layer effectively , make board shoulder muscle antiabrasion layer cross thick producing cracking.4. control good sand , stone in a foot-path and mud content strictly. The thick sand in the cast-in-place board should be selected for use, a stone of foot-path between 0.25-0.5mm, the mud content of grit can't exceed 1% . Sand,, stone grains of foot-path careful and too light, mud content too big, will reduce concrete intensity, will make the concrete produce the crack finally.5. dispose certain amounts of angle muscles in four corners of the board , radiate the muscle . Take place in board corner phenomenon this more to cast-in-place board crack, corner set up all around in boardThe length radiates the muscle for about 1800mm, so as to meet demands of angle stress of the board, the stress sphere of action of making the cast-in-place board produce the crack conforms with radiation muscle, thus change and control the production of the crack effectivelyforced concrete structure reinforced with an overviewRein Since the reform and opening up, with the national economy's rapid and sustained development of a reinforced concrete structure built, reinforced with the development of technology has been great. Therefore, to promote the use of advanced technology reinforced connecting to improve project quality and speed up the pace of construction, improve labor productivity, reduce costs, and is of great significance.Reinforced steel bars connecting technologies can be divided into two broad categories linking welding machinery and steel. There are six types of welding steel welding methods, and some apply to the prefabricated plant, and some apply to the construction site, some of both apply. There are three types of machinery commonly used reinforcement linking method primarily applicable to the construction site. Ways has its own characteristics and different application, and in the continuous development and improvement. In actual production, should be based on specific conditions of work, working environment and technical requirements, the choice of suitable methods to achieve the best overall efficiency.1.1 radial squeeze linkWill be a steel sleeve in two sets to the highly-reinforced Department with superhigh pressure hydraulic equipment (squeeze tongs) along steel sleeve radial squeeze steel casing, in squeezing out tongs squeeze pressure role of a steel sleeve plasticity deformation closely integrated with reinforced through reinforced steel sleeve and Wang Liang's Position will be two solid steel bars linkedCharacteristic: Connect intensity to be high, performance reliable, can bear high stress draw and pigeonhole the load and tired load repeatedly.Easy and simple to handle, construction fast, save energy and material, comprehensive economy profitable, this method has been already a large amount of application in the project.Applicable scope : Suitable for Ⅱ , Ⅲ , Ⅳ grade reinforcing bar (including welding bad reinforcing bar ) with ribbing of φ18- 50mm, connection between the same diameter or different diameters reinforcing bar .1.2must squeeze linkExtruders used in the covers, reinforced axis along the cold metal sleeve squeeze dedicated to insert sleeve Lane two hot rolling steel drums into a highly integrated mechanical linking methods.Characteristic: Easy to operate and joining fast and not having flame homework , can construct for 24 hours , save a large number of reinforcing bars and energy.Applicable scope : Suitable for , set up according to first and second class antidetonation requirement -proof armored concrete structure φⅡ, Ⅲgrade reinforcing bar with ribbing of hot rolling of 20- 32mm join and construct live.1.3 cone thread connectingUsing cone thread to bear pulled, pressed both effort and self-locking nature, undergo good principles will be reinforced by linking into cone-processing thread at the moment the value of integration into the joints connecting steel bars.Characteristic: Simple , all right preparatory cut of the craft , connecting fast, concentricity is good, have pattern person who restrain from advantage reinforcing bar carbon content.Applicable scope : Suitable for the concrete structure of the industry , civil building and general structures, reinforcing bar diameter is for for the the 16- 40mm one Ⅱ, Ⅲgrade verticality, it is the oblique to or reinforcing bars horizontal join construct live.These are now commonly used to connect steel synthesis methods, which links technology in the United States, Britain, Japan and other countries are widely used. There are different ways to connect their different characteristics and scope of the actual construction of production depending on the specific project choose a suitable method of connecting to achieve both energy conservation and saving time limit for a project ends.References1.construction manual write the group. Construction manual. Beijing: China Construction Industry Press, 1992.2.JGJ107-96 reinforcing bar machinery connects the common technical regulation 3 GB 1499-91 The armored concrete uses the reinforcing bar.3.GB with ribbing of hot rolling 13013-91 The armored concrete uses the round reinforcing bar of hot calendaring.现浇楼板裂缝的产生与防治随着城市住宅建设步伐的加快，不少住宅小区相继建成，许多住户陆续搬进新居，他们对住房的质量要求越来越高，尤其对一些现浇楼板出现的裂缝情况非常关注，担心这些裂缝最终会引发不安全事故，而纷纷向建筑质量监督部门投诉。

外文翻译资料Construction cracks in concretecauses and preventionConstruction cracks in concrete, causes and preventionConstruction cracks of concrete reason for the external and internal. The initial mainly refers to the internal defects of concrete in early concrete, its internal hardening process will exist numerous micro-pores, air-pocket and micro cracks, External refers to the load reason: temperature crack, dry shrinkage effect etc. In these, can produce various forms of concrete cracks. To grasp the construction process of raw materials, in pouring process configuration of progress and thickness, grasp timely maintenance work well, which can avoid concrete cracks. A, The cause of the tear1.The initial defects of concreteConcrete is composed of cement, sand aggregate, mixed with water and other materials and formation of heterogeneity brittle materials. In the beginning, because hardened concrete construction and deformation, a series of problems, such as constraint in the concrete shape sclerosis will exist numerous micro-pores, air-pocket and micro cracks of concrete that usually called initial defects. Micro cracks is usually a cracks in the concrete, bearing, and some other function not harm. But under load, temperature of concrete, shrinkage and function, micro cracks will be expanded and connectivity, and finally form the visible cracks of concrete, macroscopic crack, said it was the use of concrete structure, properties and durability of adverse effects.2.The load factorDue to the tensile strength of concrete structure or structures, small as a part of the external effects of stress than concrete tensile strength, will crack. Therefore, the concrete in the load and the load, can produce a crack. To load the crack, can produce by reasonable design and construction to prevent. For the load of crack, due to reasons, it is hardto handle and prevent. The more common than load factors have temperature, dry shrinkage, settling contraction deformation, plastic shrinkage deformation, etc, in these function, can make concrete inside tensile stress.3.Big volume concrete crack formation reasonsMassive concrete cracking reasons can be divided into two types: one is the structural cracks, is caused by external load, 2 it is material of crack is not caused by the changes of deformation and temperature stress and is mainly composed of concrete's shrinkage. This article mainly discussed type materials. One specific reasons are as follows: The temperature stress caused by fracture (temperature crack) temperature cracks in the main reason is caused by temperature difference. Temperature can be divided into three types: early concrete pouring, produce large amounts of the hydration heat, due to the concrete is a poor conductor of heat accumulation in concrete, the hydration heat to send out, often make internal temperatures rise, concrete and reinforced concrete surface temperature for outdoor environment temperature, it is formed, the temperature and temperature inside of condensate in early concrete tensile stress when more than concrete compressive strength, will cause cracking in concrete, In addition, in the dismantling formwork, surface temperature and reduce the temperature caused by fast, and will cause cracking. When the concrete temperature, maximum heat radiates to the minimum temperature, temperature, or use them with the highest temperature difference is the internal temperature, These three temperature will produce temperature crack. In these three temperature, is mainly caused by hydration heat and the temperature.Shrinkage crack contraction there are many causes, including drying shrinkage, plastic shrinkage, shrinkage, carbonation contraction, etc. Here mainly introduces drying shrinkage and plastic shrinkage.After drying shrinkage of concrete sclerosis, in dry environment, the water concrete to the loss caused by inside extroversion, concrete the shrinkage deformation cracks.The plastic shrinkage of cement and concrete in the activity of higher temperature, or in low water-cement condition exacerbate cause craze. When the concrete surface water obviously decreased, lactation evaporation of water cannot get the timely supplements, then concrete is still in a state of plastic, by a concrete surface tension, uneven distribution will appear the cracks of concrete cracks, and further intensify the moisture inside body, and further expansion crack Second, the measures to prevent cracksFrom the above analysis, the crack is mainly caused by temperature difference and contraction, so in order to prevent the cracks of, will maximize reduce temperature and reduce the shrinkage of concrete, specific measures as follows.1. Optimizing raw materials(1)Cement. The cement should be chosen according to the engineering properties, construction condition, climate and other technical requirements, comprehensive consideration, to meet the strength and durability of concrete design requirements. When the choice should be labeled with cement concrete design match the label. For full strength of cement, cement, cement save from the label for concrete label 1.5 to 2 times as appropriate.(2) aggregate. (a) coarse aggregate. The coarse aggregate concrete rubble is close-grained, must have the enough strength, hard to expand the coarse aggregate size. To ensure the concrete pouring dao close-grained, coarse aggregate maximum diameter less than the minimum size of the structural sections 1/4, also not greater than the minimum distance between steel net for thickness 3/4, in 10 centimeters and concrete, allowing adoptsmaximum diameter 1 1/2 of the aggregate number, but it shall not exceed 25%. (b) fine aggregate. Sand particle gradation of technical properties of concrete influence, requests the porosity and total surface area small, small need total surface on the surface of the gravel package will reduce quantity of cement slurry, can reduce the dosage of cement hydration heat, reduce to prevent cracks. On the other hand is to control the hydraulic sand, the content of 5% in concrete, "the contraction deformation, the hydraulic and larger crack, fine aggregate to use clean in the sand.(3) admixtures. (a) water-reducing agent. Jianshuiji belongs to the surface active substances, is a kind of cement dispersant. Its main function of improving concrete workability, reduce the consumption of concrete mixture, reduce water-cement ratio increases, and improve the liquidity of concrete strength of concrete or keep in concrete cement strength must decrease, while the water-cement ratio, the dosage of cement to prevent cracking is reduced. (b) retarder. Retarder is delaying the role of concrete exothermic peak time, 2 it is to improve workability, and reduce the loss of collapsbillity. (c) air-entraining agent. In the application of concrete air-entraining agent for improving the concrete workability, can pump, improving the concrete durability is very favorable. In a certain extent increase anti-cracking performance of concrete.(4) mass concrete chooses raw materials should pay attention to the following:①The coarse aggregate gradation, appropriate USES continuous fine aggregate ZhongSha should be adopted.②Admixtures appropriate USES retarder, water-reducer, Admixtures appropriate USES fly ash, slag powder etc.③In mass concrete strength of concrete and the slump and the requirements of the premise, should improve mixing and aggregate content,in order to reduce the dosage of cement concrete alone.④ Should try to choose cement hydration heat low, setting time is long, the cement, low thermal Portland cement slag silicate cement, cement, slag dam Portland cement, coal ash Portland cement, volcanic gray Portland cement, etc.However, the slag cement hydration heat low water cement ratio of chromatography in other large, casting lots of water surface layer. This phenomenon is not only affect lactation water, also influence the construction speed and quality of construction. Because the water gathered in separation between the two casting concrete surface layer, change, and water-cement ratio in the water and took out some of the mortar, thus forming a layer of interlining content, destroyed the cohesive force of concrete and holistic. The size of the water concrete lactation with water water, water, lactation; And with the temperature, water separation of time with temperature completely and shortening, In addition, also with the composition and fineness of cement. Therefore, in selecting slag cement should be chosen when the varieties, and lactation shall be adding water-reducing agent in concrete, to reduce the consumption. During construction, should be in water or mixing some tomography uniform rolling cement casting in water, with 3-degrees vibration compaction, continue again after a concrete casting.2.the reasonable construction method(1) The concrete mixing and transportation. (a) white, accurate grasp of concrete proportion, especially the strict control of water consumption, the determination of sand. Records of every block water cement, sand and gravel, specific quantity, the application must be accurate to scale, by mixing. Good control of concrete slump and general shoulds not be too big, in 120 ± 20 mm. To minimize the mouth 3 concrete temperature. (b) concrete mixing in a storehouse after good transportprocess, to prevent to produce separation, lactation water, mortar loss should shorten transportation time, concrete loading not too full. (2)Concrete pouring and open mode. Pouring process may be close-grained, vibration to vibration time should be uniform in surface functional plasma advisable, uniform spacing, vibrating force scope affected overlap 1/2 advisable, after casting, compaction, surface must, in order to prevent the surface crack. Try to avoid in the solar radiation, high time due to the needs of the project if pouring in summer construction, avoid noon pouring temperature period, try to arrange at night. Time should be removed, according to air temperature and strength. In the actual temperature curing of the concrete conditions of strength, strength design of concrete center and 75%, the lowest temperature control surface in 25 degrees Celsius, expected the concrete surface temperature drop more than 9 degrees Celsius above does not allow removed.(3) Do surface insulation protection of mass concrete temperature crack, is mainly caused by excessive temperature. Concrete pouring, due to internal heat faster, more surface temperature will form the internal and external surface by internal restraint, contraction, but the tensile stress, not more than usually have small tensile strength and the concrete cracks. But if the air raid, or by excessive ventilation cooling, make the surface temperature will easily lead to excessive temperature crack in the concrete, and so on, especially after dismantling formwork, low season in the immediate surface protection. To prevent excessive temperature crack, cause surface. In addition, the average day temperature in 2 ~ 3d consecutive decline not less than 6 ~ 8 degrees Celsius, 28d age concrete surface must surface within the protection.(4) Of the mass concrete casting:Construction scheme, besides should satisfy each place of concrete in early before a new concrete are covered and rammed finished outside,still should consider structure size, steel pipe, buries the bolts and leave, concrete and hydration heat supply, the influence of factors such as the commonly used method has the following kinds:Comprehensive stratified:In the first layer after pouring all comprehensive casting, casting back second, should make the first layer of concrete yet, so early, continuous casting until completion by far. Using this scheme, applicable to the general structure of planar size shoulds not be too big, when construction from the short side began to push along the long side, is more appropriate. When necessary, can be divided into two sections from middle to both ends to or from the middle and construction.Section 2 layer:Concrete casting, starting from scratch, casting a certain distance to the second floor, so after pouring in other layers on casting. Due to the total number of layers, therefore, after the first layer top pouring concrete yet at the end of the beginning of the second period, and can turn from layered casting. This scheme is applicable to units within the time required, the supply of concrete less like the first option on that. This scheme is applicable to structure is too big and thickness of large area or length.Incline stratified:Requirements of slope not greater than cant 1/3, applicable to greatly exceed the length of the structure of the thickness of the three times. From the bottom layer of concrete casting, gradually move.3.maintenance measuresMaintenance of mass concrete construction is a vital work. Maintain proper maintenance is mainly to control temperature and humidity, temperature, promote concrete outside the normal development of the strength of concrete and prevent the cracks of concrete and development.According to the specific circumstances of should as far as possible much maintenance period of time, after dismantling formwork should immediately, covering protection to prevent recent climate, sudden cold temperature, prevent and control in early concrete cracks and medium. The massive concrete curing, not only to satisfy the need that still should increase by artificial temperature control, due to temperature caused by deformation of the concrete cracking. After the completion of the concrete curing time to keep the concrete surface spraying maintenance, such as reducing often humid heat outside pour cans, and prevent dry crack and promote the stable growth of concrete strength. In general 18h 12 ~ after pouring in immediately start maintenance, maintenance time not less than 28d or design age.4 CooledIf in the high-temperature seasonal construction, should be in early general refrigeration adopted to reduce the water temperature, but the peak of concrete, water cannot too long, for a long time can cause excessive temperature range of temperature stress caused by large. In order to cut inside and outside, still should temperature in summer jiamoqiuchu undertake metaphase is cooled by water, river, general middle water lasted about two months. Later, water is made concrete cylindrical blocks the necessary measures to juncture grouting, generally USES water and cooling water through the combination scheme.Third, the conclusionConcrete crack, especially large volume concrete crack is currently scholars and engineering is an important problem of attention, through the above analysis, the material of mass concrete crack is mainly composed of temperature stress and concrete's shrinkage, the author thinks carefully select material, and in the use of reasonable construction method, can effectively prevent the cracks.混凝土施工裂缝原因及防治混凝土施工裂缝原因不外乎外因和内因。

混凝土裂缝处理Concrete cracks generally occur due to shrinkage of concrete when it is hardening or due to temperature changes, leading to fractures in concrete due to external forces. The treatment of concrete cracks is mainly divided into two aspects: preventive treatment and basic treatment.预防性处理1、防止裂缝发生。

在混凝土浇筑、加固过程中，应注意操作技巧，控制混凝土的收缩和热胀冷缩，尽量减少混凝土的空气保护和开裂的发生。

2、采用适当的混凝土配方和抗裂剂。

使用优质的砂、石材及适量的抗裂剂，以克服混凝土热胀冷缩的不良现象。

3、有效的作业技术。

采用合理的浇筑技术，控制合理的胶凝，把混凝土块状化，减少收缩空隙，降低水灰比，增大空隙率，减少对混凝土的抗拉力，防止混凝土裂缝产生和扩大。

4、采用穿孔化学凝结法进行混凝土预加固、专用土工布或其他物料进行浇筑物预处理，延缓混凝土收缩和热胀冷缩。

基本处理1、未发生植被、开裂及降解的裂缝，使用植被垫层、黏结剂、粘结剂和密封剂对裂缝进行封闭、粘结和密封。

2、已发生植被、开裂和降解的裂缝，应使用抗裂剂、抗开裂增强材料和抗拉力增强材料进行处理。

3、处理时，应注意裂缝的深度。

深度低于50毫米的裂缝，可采用不太厚的材料进行修补；裂缝深度超过50毫米的，需采用较厚的材料进行封闭和固定，一般使用的材料厚度较厚，由于混凝土的抗压性能较好，可以采用。

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.。

The causes, prevention and treatment of cracks in concrete Abstract:In the building construction concrete cracks a quality common problem, the causes of cracks in concrete, prior prevention, as well as after the repair process is a more common phenomenon in the process of building production, should be taken seriously enough. The concrete is a brittle material of a gravel aggregate, cement, water and other additional material formed by mixing a non-homogeneous. Concrete construction and deformation constraints and a series of problems, there are a large number of micro-porosity, cavitation and micro-cracks in the concrete hardening molding. The author combines his engineering work experience, summed up the cracks in concrete causes and prevention measures.Keywords: causes of cracks in concrete preventive treatmentIn building construction, concrete cracks is a widespread problem, cracks solution is a more difficult problem. Cracks in concrete reasons are manifold, deformation: such as contraction, expansion, settlement and other causes cracks; external load caused by: improper maintenance of concrete; cracks caused by the external additive problems.Concrete cracks, if not prevention measures to solve, extending its further development will lead to the internal reinforcement corrosive, reducing the carrying capacity of the reinforced concrete structure, impermeability, durability useful life, and even affect people's lives and property safety . Crack is impossible to completely eliminate the engineering specification expressly provides some structure in which the different conditions, allowing the existence of a certain width and depth of the crack. But in the construction process should be as far as possible to take effective preventive and technical safeguards to effectively control the cracks, as little as possible or minimize crack width, depth, and in particular to avoid in key positions or harmful cracks.1.Causes and types of concrete cracksThe concrete is a brittle material of a gravel aggregate, cement, water and other additional material formed by mixing a non-homogeneous. Hardening molding concrete concrete construction and deformation constraints there are a large number of micro-porosity, cavitation and micro-cracks, precisely because of the existence of these initial defects before the concrete showing some heterogeneity characteristics . Micro-cracks is usually a harmless cracks on concrete load-bearing, seepage and use the function does not cause harm. But in the concrete under load, temperature effects, the micro-cracks will continue to expand and connectivity, and ultimately the formation of visible macro cracks, the cracks is often said that the concrete works.Many cracks in concrete cracks caused by deformation: such as temperature change, shrinkage, expansion, uneven subsidence caused cracks; external load induced cracks; cracks caused by improper conservation of the environment and chemical action, etc. .Common cracks in the concrete are the following: (1) shrinkage cracks; ②plastic shrinkage cracking; (3) settlement cracks; ④temperature cracks; ⑤chemical reaction caused by cracks.2.Concrete cracks and prevention2.1 Shrinkage cracks and prevention ofShrinkage cracks appear in a week or so after the end of the concrete curing period of time or after concrete pouring. The evaporation of the water in the slurry will produce shrinkage, and the shrinkage is irreversible. Drying shrinkage cracks are mainly caused due to the different degree of evaporation of the moisture inside and outside the concrete result of deformation of the type: concrete affected by the influence of external conditions, excessive surface moisture loss, large deformation, internal humidity changes smaller deformation smaller, the larger the surface shrinkage deformation by concrete internal constraints, have a greater tensile stress cracks. The lower the relative humidity, the greater the shrinkage of cement paste shrinkage cracks are easy to produce. Shrinkage cracks parallel to the surface of the linear or reticular light fine cracks, width of more than 0.05 to 0.2 mm between the flat parts more common in mass concrete, thin flat-slab along the short to distribution. Shrinkage cracks usually affect the impermeability of concrete, causing corrosion of steel affect the durability of concrete, water pressure will produce hydraulic fracturing affecting concrete bearing capacity. The concrete shrinkage main and to the water-cement ratio of the concrete, cement component, the amount of cement used, thenature and amount of aggregate, the amount of admixture.The main preventive measures:(1)Selection of a smaller amount of shrinkage cement, commonly used in low heat cement and fly ash cement, reduce the amount of cement.(2)Concrete shrinkage by water-cement ratio, the greater the water-cement ratio, the greater the shrinkage in the concrete mix design should try to control the selection of a good water-cement ratio, while mixing the water-reducing agent .(3)Strict control than with concrete mixing and construction, concrete water consumption must not be greater than the amount of water given by the mixture ratio design.(4)To strengthen the early curing of concrete and appropriate to extend the concrete curing time. Appropriate to extend the winter construction concrete insulation cover, and brushing curing agent curing.(5) Set the appropriate contraction joints in concrete structures2.2 Plastic shrinkage cracks and preventionThe plastic shrinkage refers to the before condensation, the concrete surface due to rapid dehydration resulting contraction. Plastic shrinkage cracking is generally hot and dry or windy weather, the cracks mostly wide in the middle, both ends of the thin and vary in length, non-coherentstate. Short cracks as long as 20 to 30cm the longer cracks of up to 2 to 3 m, width of 1 to 5 mm. Main causes: the concrete before the final setting almost no strength or intensity is very small or just the final setting concrete small strength, high temperature or a larger wind, the concrete surface excessive water loss, resulting in capillary have a greater negative pressure of the concrete volume of a sharp contraction, but this time the strength of the concrete can not resist its own contraction, resulting in cracking. The main factors affecting the plastic shrinkage cracking water-cement ratio, the setting time of the concrete, the ambient temperature, wind speed, relative humidity, and so on.The main preventive measures:(1) Selection of shrinkage values smaller high early strength Portland cement or ordinary Portland cement.(2) Strict control of water-cement ratio, to increase the slump and workability of the concrete, to reduce the amount of cement and water mixed with superplasticizer.(3) Pouring concrete before watering the grass roots and templates evenly soaked.(4) Timely covered by plastic film or wet straw, hemp sheet to maintain final setting of concrete the moist front surface or the surface of the concrete spraying curing agent for conservation.To set the sun and wind facilities .(5) At high temperatures and windy weather, timely conservation.2.3 subsidence cracks and preventionSubsidence cracks caused by structural foundation soil is uneven, soft, or backfill or flooding due to uneven settlement; template stiffness, the template support spacing is too large or the bottom of the support as a result of loose, especially in the template support winter on the frozen ground, permafrost thaw uneven settlement, resulting in the concrete structure cracks. Such cracks are deep into or through the cracks, toward subsidence, generally along the perpendicular to the ground or in the form of an angle of 30 °to 45 °direction, subsidence cracks tend to have a certain amount of dislocation, crack width is often and is proportional to the amount of the settlement. Crack width was less affected by temperature changes. Ground deformation stability, subsidence cracks basically stabilized.The main preventive measures:(1)on the soft soil, filling foundation should be carried out prior to the construction of the superstructure necessary compaction and reinforcement.(2)to ensure that the template has a sufficient strength and stiffness, and firmly support the foundation uniform force.(3) prevent the process of concreting the foundation is immersed inwater.(4) template removal time can not be too early, and pay attention to the order form removal.(5) in the erection of the template on the permafrost to take certain precautions.2.4 Temperature cracks and preventionTemperature cracks occurred in mass concrete surface or larger changes in temperature regions in concrete structures. Concrete pouring, in the hardening process of cement hydration reaction to produce large amounts of heat of hydration (when the amount of cement per cubic meter of concrete will release 17,500 27500kJ heat at 350 to 550 kg/m3, so that the internal temperature of the concrete SITA about 70 °C or higher). Cause the internal temperature to rise sharply due to the larger volume of concrete, the accumulation of a large amount of heat of hydration within the concrete and easy to distribute, and rapid cooling of the surface of the concrete, thus forming a larger temperature difference inside and outside, the larger the temperature difference caused by the internal and external different degrees of thermal expansion and contraction of the concrete surface tensile stress (Practice has proved that when the temperature difference between inside and outside of the concrete itself is 25 ° C to 26 °C, will produce roughly about10MPa concrete tensile stress). When the tensile stress exceeds the ultimate tensile strength of the concrete, the concrete surface cracks, cracks occurred in the concrete construction in the late. Concrete construction when the temperature changes, or concrete attacked by the cold wave will lead to concrete surface temperature sharp decline, and contraction, contraction of the concrete surface bound by internal concrete, will produce large tensile stress. cracks, such cracks are generated in the the shallow concrete surface within the range of usually only.The trend of temperature cracks usually certain rules, often criss-cross a large area of structural cracks; the length of the beam and plate size larger structures, cracks parallel to the short side; deep and penetrating temperature cracks are generally parallel or nearly parallel to the direction of the short side , cracks along the longest edge segments appear more dense middle. Crack width sizes, affected by temperature changes more obvious, summer, winter wide narrow. The high temperature expansion caused by the concrete temperature is usually middle coarse fine at both ends, while the the shrink cracks thickness less obvious changes. The emergence of such cracks can cause corrosion of steel, concrete carbonation, reduce freeze-thaw resistance of concrete, anti-fatigue and impermeability.The main preventive measures:(1) try to use low heat or moderate heat cement, slag cement, fly ash cement.(2) reduce the amount of cement to try to control the amount of cement 450kg/m3.(3) reduce the water-cement ratio, generally water-cement ratio of concrete is controlled below 0.6.(4) improve the aggregate gradation, fly ash or superplasticizer to reduce the amount of cement, lower heat of hydration.(5) improve the concrete mixing process, "secondary air" traditional "cold" on the basis of new technology, reduce the temperature of concrete pouring.(6)a certain amount of concrete admixture having less water, plasticizers, retarding admixture role to improve the fluidity of the concrete mixture, water retention, reduce the heat of hydration, delaying the time of occurrence of the thermal peak.(7)hot season puts up visor and other auxiliary measures to control the temperature rise of the concrete pouring, to reduce pouring concrete temperature.(8)mass concrete temperature stress associated with the structure size, the larger the size of the concrete structure, the greater the temperature stress, so reasonable arrangements for the construction process, hierarchical, block pouring, to facilitate cooling, reducingconstraints.2.5 chemical reaction caused cracks and preventionAlkali-aggregate reaction cracks and steel corrosion cracks caused by the most common due to the chemical reaction caused by cracks in the reinforced concrete structure. Concrete mixing will produce some of the alkaline ions, these ions produce a chemical reaction with certain reactive aggregate and absorbs water in the surrounding environment and the volume increases, resulting in concrete crisp, expansion cracking. Such cracks usually appear in the concrete structure during use, in the event difficult to remedy, should take effective measures to prevent it in the construction. Concrete pouring poor vibrators or reinforced protective layer is thin, harmful substances into the concrete reinforcing bars from corrosion, the corroded reinforcement volume expansion, leading to concrete Splitting the cracks of this type of longitudinal cracks along the location of reinforcement .The main preventive measures:(1) selection of the alkali reactivity of small sand and gravel aggregate.(2) selection of low-alkali cement and admixtures of low-alkali or alkali.(3) selection of a suitable admixture AAR with.3 crack treatmentCracks in concrete remedial measures mainly the following methods: surface repair method, grouting, caulking closure method, structural reinforcement, concrete replacement method, electrochemical protection and legal bionic self-healing.3.1 Surface repair methodSurface repair method is a simple, common repair method, the action is in the cracks in the surface of the painting grout, epoxy mortar or concrete surface coating paint, anti-corrosion materials such as asphalt, concrete protection at the same time in order to prevent various The Effect of cracking, usually can paste in cracks in the surface of the glass fiber cloth and other measures.3.2 grouting, caulking closure methodThe grouting method is the use of pressure equipment cementing material is pressed into the cracks in the concrete, the cementing material hardened concrete to form a whole, and thus play the purpose of plugging consolidation. Top cementing material grout, epoxy, methacrylate, polyurethane and other chemical materials. The filleting gouges along the cracks in the tank filled, the plastic or rigid sealing material, in order to achieve the purpose of closed cracks. Commonly used plastic materialsare PVC, clay, plastic ointment, butyl rubber, etc.; rigid sealing material is a polymer cement mortar.3.3 Structural reinforcement methodWhen the the cracks impact on the performance of concrete structures, to take structural reinforcement concrete structure. Commonly used in the following ways: structural reinforcement to increase the cross-sectional area of the concrete structure, corner in the component outsourcing steel, prestressed Reinforcing paste the steel reinforcement, additional the fulcrum reinforcement and shotcrete reinforcement.3.4 Concrete replacement methodThe concrete substitution method is an effective method for dealing with serious damage to the concrete, this method is deteriorated concrete is removed first, and then replaced into the new concrete or other materials. Top replacement materials: of Ordinary concrete or cement mortar, polymer or polymer modified concrete or mortar.3.5 electrochemical Protection ActCathodic protection, chloride extraction, alkaline recovery method, the use of the electrochemical action of the applied electric field in the medium, to change concrete or reinforced concrete in which the state of the environment, passivated steel, in order to achieve the purpose ofanti-corrosion.3.6 biomimetic self-healing legalBionic self-healing legitimate the traditional components of the concrete in some special components such as liquid-core fibers or capsules containing binder, formed within the concrete the intelligent bionic self-healing neural network system, when the concrete cracks secreted part of the liquid core fiber cracks can heal again. Conclusion:Cracks is a common phenomenon in the concrete structure, its appearance will not only reduce the impermeability of the building, affect the use of the building, and would lead to corrosion of steel, concrete carbonation, reduce the durability of the materials, the impact the carrying capacity of the building, so to carefully study the concrete cracks, be treated differently, using a reasonable method for processing to take effective preventive measures to prevent the emergence and development of cracks in the construction, to ensure the safety of buildings and structures and stable work.混凝土裂缝的成因、预防及处理摘要：在建筑工程施工中混凝土裂缝的产生是一项质量通病，因此对混凝土裂缝的成因分析、事先预防，以及产生后的修补处理是建筑生产过程中较为普遍的现象，应引起足够的重视。

本科生毕业设计 (论文) 外文翻译原文标题Building construction concrete crack of prevention and processing译文标题建筑施工混凝土裂缝的预防与处理作者所在系别建筑工程作者所在专业土木工程作者所在班级B13412作者姓名李泽顺作者学号201323024指导教师姓名白有良指导教师职称高工完成时间2017 年 3 月北华航天工业学院教务处制毕业设计（论文）外文翻译毕业设计（论文）外文翻译毕业设计（论文）外文翻译四是改善骨预测类一起去,陈加粉火山灰炉子或有效地减少水等来减少水泥用量,降低水热转。

五是改善混凝土混合混合处理工艺,降低浇混凝土建造的温度。

陈六的另外添加一个固定数量的减少水和增加苏,缓慢Ning等具体功能,改善混凝土混合匹配的流动性,保护水,降低水转热,推迟热峰出现的时间。

七是热季节洒构建采用可以采取建立隐藏阳光板等援助措施控制混凝土的温,建立混凝土洒温度下降。

八大体积混凝土的温度应该是力与结构尺寸、混凝土结构尺寸更大,温度应该力更大,所以要合理安排施工工序,分层,分件洒构建,为方便在热传播,让控制。

九是在伟大的内在物理卷的宪法部分混凝土冷却管道、冷水也许冷空气冷却,让混凝土的内外温差。

十是加强混凝土温度的监督,采取及时降温,保护措施。

11是储备温度收缩缝。

12是让控制,之前撒上适当的建筑混凝土霁岩石和旧混凝土前建立一个5毫米左右的砂垫层或使用沥青等材料涂刷.13是保护,加强混凝土混凝土后浇构建使用潮湿的草丽安,麻片等覆盖,和关注撒水保护,适当延长保护时间,保证混凝土表面缓慢移动的酷off.At寒冷的季节,混凝土表面应宪法保温措施,以防止寒潮袭击。

14是分配少量的混凝土钢筋可能添加纤维材料混凝土温度裂缝控制在一定的范围内。

5.化学反应导致碱性骨骼发生裂纹和预防反应裂纹和钢筋锈蚀引起的裂纹是由于化学反应而引起的裂纹引起的钢筋混凝土结构中最为熟悉的。

附录Building construction concrete crack ofprevention and processingIn the concrete engineering the familiar crack and the prevention(1)Stem Suo crack and prevention-0.2 mm, the flat surface part much see in the big physical volume concrete and follow it more in thinner beam plank short to distribute.Stem Suo crack usually the anti- Shen of influence concrete, cause the durable of the rust eclipse influence concrete of reinforcing bar, under the function of the water pressure dint would creation the water power split crack influence concrete of loading dint etc..Concrete stem the Suo be main with water ash of the concrete ratio, the dosage of the composition, cement of cement, gather to anticipate of the dosage of the property and dosage, in addition etc. relevant.Main prevention measure:While being to choose to use the constringency quantity smaller cement, general low hot water mire and powder ash from stove cement in the adoption, lower the dosage of cement.Two is a concrete of stem the Suo be subjected to water ash ratio of influence more big, water ash ratio more big, stem Suo more big, so in the concrete match the ratio the design should as far as possible control good water ash ratio of choose to use, the Chan add in the meantime accommodation of reduce water.Three is strict control concrete mix blend with under construction of match ratio, use of concrete water quantity absolute can't big in match ratio design give settle of use water quantity.Four is the earlier period which strengthen concrete to protect, and appropriate extension protect of concrete time.Winter construction want to be appropriate extension concrete heat preservation to overlay time, and Tu2 Shua protect to protect.Five is a constitution the accommodation is in the concrete structure of the constringency sew.(2)The Su constringency crack and preventionSu constringency is the concrete is before condense, surface because of lose water quicker but creation of constringency.The Su constringency crack is general at dry heat or strong wind the weather appear, crack's much presenting in the centerbreadth, 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, therefore creation cracked.The influence concrete Su constringency open the main factor of crack to have water ash ratio, concrete of condense time, environment temperature, wind velocity, relative humidity...etc..Main prevention measure:One is choose to use stem the Suo value smaller higher Huo sour salt of the earlier period strength or common the Huo sour brine mire.Two is strict the control water ash ratio, the Chan add to efficiently reduce water to increment the collapse of concrete fall a degree and with easy, decrease cement and water of dosage.Three is to sprinkle before building concrete, water basic level and template even to soak through.Four is in time to overlay the perhaps damp grass mat of the plastics thin film, hemp slice etc., keep concrete eventually before the Ning surface is moist, perhaps spray to protect etc. to carry on protect in the concrete surface.Five is in the heat and strong wind the weather to want to establish to hide sun and block breeze facilities, protect in time.(3)Sink to sink crack and preventionThe creation which sink to sink crack is because of the structure foundation soil quality not and evenly, loose soft or return to fill soil dishonest or soak in water but result in the asymmetry sink to decline with the result that;Perhaps because of template just degree shortage, the template propped up to once be apart from big or prop up bottom loose move etc. to cause, especially at winter, the template prop up at jelly soil up, jelly the soil turn jelly empress creation asymmetry to sink to decline and cause concrete structure creation crack.This kind crack many is deep enter or pierce through sex crack, it alignment have something to do with sinking to sink a circumstance, general follow with ground perpendicular or present 30 °s-45 °Cape direction development, bigger sink to sink crack, usually have certain of wrong, crack width usually with sink to decline quantity direct proportion relation.Crack width under the influence of temperature variety smaller.The foundation after transformstability sink to sink crack also basic tend in stability.Main prevention measure:One is rightness loose soft soil, return to fill soil foundation a construction at the upper part structure front should carry on necessity of Hang solid with reinforce.Two is the strength that assurance template is enough and just degree, and prop up firm, and make the foundation be subjected to dint even.Three is keep concrete from sprinkle infusing the foundation in the process is soak by water.Four is time that template tore down to can't be too early, and want to notice to dismantle a mold order of sequence.Five is at jelly soil top take to establish template to notice to adopt certain of prevention measure.(4)Temperature crack and preventionTemperature crack much the occurrence is in big surface or difference in temperature variety of the physical volume concrete compare the earth area of the concrete structure.Concrete after sprinkling to build, in the hardening the process, cement water turn a creation a great deal of of water turn hot, .(be the cement dosage is in the 350-550 kg/m3, each sign square the rice concrete will release a calories of 17500-27500 kJ and make concrete internal thus the temperature rise to reach to 70 ℃or so even higher)Because the physical volume of concrete be more big, a great deal of of water turn hot accumulate at the concrete inner part but not easy send forth, cause inner part the temperature hoick, but the concrete surface spread hot more quick, so formation inside outside of bigger difference in temperature, the bigger difference in temperature result in inner part and exterior hot the degree of the bulge cold Suo dissimilarity, make concrete surface creation certain of pull should dint.When pull should dint exceed the anti- of concrete pull strength extreme limit, concrete surface meeting creation crack, this kind of crack much occurrence after the concrete under construction period.In the concrete of under construction be difference in temperature variety more big, perhaps is a concrete to be subjected to assault of cold wave etc., will cause concrete surface the temperature sharply descend, but creation constringency, surface constringency of the concrete be subjected to inner part concrete of control, creation very big of pull should dint but creation crack, this kind of crack usually just in more shallow scope of the concrete surface creation.The alignment of the temperature crack usually none settle regulation, big area structure the crack often maneuver interleave;The size bigger structure of the beam plank length, the crack run parallel with short side more;Thorough with pierce through sex of temperature crack general and short side direction parallelism or closeparallelism, crack along long side cent the segment appear, in the center more airtight.Crack width the size be different, be subjected to temperature variety influence more obvious, winter compare breadth, summer more narrow.The concrete temperature crack that the heat inflation cause is usually in the center the thick both ends be thin, but cold Suo crack of thick thin variety not too obvious.The emergence of the this kind crack will cause the rust eclipse of reinforcing bar, the carbonization of concrete, the anti- jelly which lower concrete melt, anti- tired and anti- Shen ability etc..Main prevention measure:One is as far as possible choose to use low hot or medium hot water mire, like mineral residue cement, powder ash from stove cement...etc..Two is a decrease cement dosage, cement dosage as far as possible the control is in the 450 kg/m3 following.Three is to lower water ash ratio, water ash of the general concrete ratio control below 0.6.Four is improvement the bone anticipate class to go together with, the Chan add powder ash from stove or efficiently reduce water etc. to come to reduce cement dosage and lower water to turn hot.Five is an improvement concrete of mix blend to process a craft, lower sprinkle of concrete to build temperature.Six is the in addition that the Chan add a have of fixed amount to reduce water and increase Su, slow Ning etc. function in the concrete, improvement the concrete mix to match a thing of mobility, protect water, lower water to turn hot, postpone hot Feng of emergence time.Seven is the heat season sprinkle to build can the adoption take to establish to hide sun plank etc. assistance measure control concrete of Wen Sheng, lower to sprinkle temperature of build the concrete.Eight is the temperature of big physical volume concrete should the dint relate to structure size, concrete structure size more big, temperature should dint more big, so want reasonable arrangement construction work preface, layering, cent the piece sprinkle to build, for the convenience of in spread hot, let up control.Nine is at great inner part constitution of the physical volume concrete cool off piping, cold water perhaps cold air cool off, let up concrete of inside outside difference in temperature.Ten is the supervision which strengthen concrete temperature, adopt to cool off in time, protection measure.11 is to reserve temperature constringency to sew.12 is to let up to control, sprinkle proper before building concrete in the Ji rock and old concrete top build a 5 mm or so sand mat a layer or usage asphalt etc. material Tu2 Shua.13 is to strengthen concrete to protect, the concrete after sprinkle build use moist grass Lian in time, hemp slice's etc. overlay, and attention sprinkle water to protect, appropriateextension protect time, assurance the concrete surface be slow-moving cool off.At the cold season, concrete surface should constitution heat preservation measure, in order to prevent cold wave assault.14 is the allocation be a little amount in the concrete of reinforcing bar perhaps add fiber material concrete of temperature crack control at certain of scope inside.(5)Crack and prevention that the chemical reaction causeAlkali bone's anticipating the crack that reaction crack and reinforcing bar rust eclipse cause is the most familiar in the reinforced concrete structure of because of chemical reaction but cause of crack.The concrete blend a future reunion creation some alkalescence ion, these ion with some activity the bone anticipate creation chemical reaction and absorb surroundings environment in of water but the physical volume enlarge, make concrete crisp loose, inflation open crack.In this kind of crack general emergence concrete structure usage period, once appear very difficult remediable, so should at under construction adopt valid the measure carry on prevention.Main of prevention measure:While being to choose to anticipate with the alkali activity small freestone bone.Two is the in addition which choose to use low lye mire with low alkali or have no alkali.Three is the Chan which choose to use accommodation with anticipate to repress an alkali bone to anticipate reaction.Because the concrete sprinkle to build, flap Dao bad perhaps is a reinforcing bar protection layer thinner, the harmful material get into concrete to make reinforcing bar creation rust eclipse, the reinforcing bar physical volume of the rust eclipse inflation, cause concrete bulge crack, the crack of this kind type much is a crack lengthways, follow the position of reinforcing bar ually of prevent measure from have:One is assurance reinforcing bar protection the thickness of the layer.Two is a concrete class to go together with to want good.Three is a concrete to sprinkle to note and flap Dao airtight solid.Four is a reinforcing bar surface layer Tu2 Shua antisepsis coating.Crack processingThe emergence of the crack not only would influence structure of whole with just degree, return will cause the rust eclipse of reinforcing bar, acceleration concrete of carbonization, lower durable and anti- of concrete tired, anti- Shen ability.Therefore according to the property of crack and concrete circumstance we want differentiation to treat, in time processing, with assurance building of safetyusage.The repair measure of the concrete crack is main to have the following some method:Surface repair method, infuse syrup, the Qian sew method, the structure reinforce a method, concrete displacement method, electricity chemistry protection method and imitate to living from heal method.Surface repair the method be a kind of simple, familiar of repair method, it main be applicable to stability and to structure loading the ability don't have the surface crack of influence and deep enter crack of processing.The processing measure that is usually is a surface in crack daubery cement syrup, the wreath oxygen gum mire or at concrete surface Tu2 Shua paint, asphalt etc. antisepsis material, at protection of in the meantime for keeping concrete from continue under the influence of various function to open crack, usually can adoption the surface in crack glue to stick glass fiber cloth etc. measure.(From:Canadian Journal of Civil Engineering)建筑施工混凝土裂缝的预防与处理混凝土工程中常见裂缝及预防:(1)干缩裂缝及预防干缩裂缝一般较多出现在混凝土的养护后的一段时间,或者是混凝土浇筑完后的一周时间左右。

中英文资料对照外文翻译Causes and control measures of concrete cracks study the problemKeywords: Causes prevention of concrete cracksAbstract: At present, paid close attention to the problem of concrete cracks, this crack in the concrete on the basis of classification, analysis of the causes of different cracks, and proposed measures to crack prevention and treatment.1.IntroductionIs the maximum amount of concrete as a building material, widely used in industrial and civil construction, agriculture and forestry with urban construction, water conservancy works in the harbor. However, many concrete structures occurs during the construction and use of different degrees and different forms of fracture. This not only affects the appearance of the building, but also endanger the normal use of buildings and structures durability.Therefore, the cracks become people concerns. In recent years, with the ready-mixed concrete and vigorously promote the use and structure become increasingly large, complex, making the problem even more prominent.However, cracks in concrete structures is a fairly common phenomenon, large number of engineering practice and modern science on the concrete strength of micro studies show that the structures of the crack is inevitable, which is a property of the material. Therefore, the scientific treatment of cracks in the crack problem is to classify on the basis, adopt effective measures to harmful levels of crack control to the extent permitted. This concrete structure will cause cracks in common, control measures and the repair method to analyze some light.2.Classification of concrete cracks2.1 Divided by Crack According to the causes of concrete cracks, structural cracks and can be divided into two major categories of non-structural cracks.(1) Structural cracks Caused by a variety of external loads cracks, also called load cracks. It includes the external loads caused by the direct stress cracks and the structure under external loads caused by secondary stress cracks.(2) Non-structural cracks Deformation caused by the change from a variety of cracks. It includes temperature, shrinkage and swelling caused by factors such as differential settlement cracks. Such cracks in the structure when the deformation is restricted due to the stress caused. Research data from abroad and a large number of engineering practice, non-structural cracks in the works in the majority, about 80%, which led to shrinkage cracks.2.2Divided by the time the cracks(1)Cracks during construction Including plastic shrinkage cracks, settlement shrinkage cracking, drying shrinkage cracks, shrinkage cracks itself, the temperature cracks, the cracks were improper construction operations, the role of early frost, and some irregular cracks caused by cracks.(2)Use of crack during Including the expansion of steel corrosion cracks generated, salt and acid erosion type liquid medium caused by cracks, the cracks caused by freezing and thawing, alkali aggregate reaction, and cracks caused by cyclic loading cumulative damage caused by cracks.2.3Classification of fractured by cracks in the shape of the shape can be divided by:(1)Longitudinal cracks parallel to the bottom component, the distribution along tendons, mainly caused by the role of steel corrosion(2)Transverse cracks perpendicular to the bottom component mainly by the loading, temperature effects caused(3)Shear cracks due to displacement caused by vertical load or vibration(4)Diagonal cracks eight shaped or herringbone cracks, common in the wall of concrete beams, mainly due to the uneven foundation settlement, and thermal effects caused by(5)X-shaped cracks common in the framework of beams, columns and walls on the ends, due to the impact effect, or moment loads caused by earthquake(6)All kinds of irregular cracks such as repeated freezing and thawing, or fires caused by cracksIn addition, concrete mixing and transport time for long cracks due to mesh, squareappears floor slab or plate surface radial cracks appear in the cross cracks and so on.2.4 The development of the state divided by cracksAccording to fracture the movement in which the state and development trends, can be divided into the following categories:(1)Stable crack This crack does not affect the persistence of applications, including two types.One is in motion the process of self-healing of fractures could be common in a number of new water projects, this is because the crack of cement particles in the leakage of water further compounds the process, precipitate Ca (OH) 2 crystal and part of the Ca ( OH) 2 has dissolved in the water with CO2 carbonation reaction to form CaCO3 crystallization occurs, both the formation of cracks in the gel material will be glued closed, and thus stop the leakage, cracks to heal. The other is in a stable movement of the cracks, such as the periodic load generated by the cyclical expansion and closure of cracks.(2)Unstable crack This will result in instability of crack extension, affecting the sustainable use of structures, should be considered part of its expansion, to take corresponding measures.3.Causes of cracks in concrete and control measures3.1 Shrinkage cracks Shrinkage cracks are caused by the humidity, it accounts for non-structural cracks in concrete in the main part. We know that concrete is a cement as the main cementing material to natural sand, stone aggregate mixing water, after casting molding, hardens and the formation of artificial stone.In the construction, in order to ensure its workability, often adding cement hydration than water needed for 4 to 5 times more water. More of these water to free state exists, and the gradual evaporation of the hardening process, resulting in the formation of large pores inside the concrete, voids or holes, resulting in volume shrinkage of concrete. In addition, the hardening process of concrete hydration and carbonation of concrete volume will lead to shrinkage. According to the experimental determination of the ultimate shrinkage of concrete is about 0104% ~ 0106%.Shows that shrinkage is the inherent physical properties of concrete, in general, the larger water-cement ratio, the higher the concrete strength, aggregate less, the higher the temperature, surface water loss is larger, the larger the value of its contract, the more easily shrinkage cracks. According to the formation of shrinkage cracks and formation mechanism of the time, works in the common shrinkage cracksare mainly plastic shrinkage cracks, settlement shrinkage cracking and drying shrinkage cracks in three categories, in addition to their contract (chemical shrinkage) cracks and carbonation shrinkage cracks.3.1.1Plastic shrinkage cracks Plastic shrinkage cracks in concrete plastic stage, before the final set. The cause of this is concrete paste and quickly evaporating water flow to the surface, with the increase in water loss, capillary negative pressure generated by contraction of the concrete surface of the drastic volume shrinkage. Strength of concrete at a time has not yet formed, which resulted in cracking of the concrete surface.This multi-cracks in dry weather, hot and windy, the fracture shallow, intermediate width, both ends of the fine, of different lengths, and disconnected.3.1.2 Settlement shrinkage cracking Settlement shrinkage cracks in concrete pouring about half an hour after the occurrence and hardening stops. The cause of this is occurring after the slurry in the Pouring uneven sink, sinking of coarse aggregate, cement grout float, when the settlement was inhibited (such as steel or embedded parts of the block) is due to shearing and cracking of the concrete. In addition, floating in the plasma layer formed on the surface will be a result of bleeding and cracking.This multi-cracks in the concrete surface, and pass along the long direction of the reinforcement, or the stirrups the distribution width of both ends of the narrow middle, is a common early cracks, especially in the pump construction is more common.3.1.3 Drying shrinkage cracks Drying shrinkage cracks in the concrete curing only appeared after completion. Its formation was mainly due to the concrete to harden, the water evaporation caused by shrinkage of the concrete surface, when the shrinkage deformation of concrete by internal constraint, have a greater tensile stress to crack the concrete surface is pulled.Shrinkage cracks on the surface generally produces very shallow location, multi-component along the short direction of distribution, were parallel, linear, or mesh, can be severe throughout the member section.3.1.4 Self-shrinkage cracks Shrinkage cracks itself has nothing to do with the outside humidity, but because of the hydration reaction of cement clinker in the process, the reaction resultant of the average density of smaller volume shrinkage caused by system (called chemical shrinkage) due. Mainly due to hydration products of free water into a part of it39;s specific volume reduced by 1 / 4 (ie 0125cm3Pg).Therefore, the chemical shrinkage of the sizeof the reduction depends on the chemical combination of cement hydration products in the amount of water.3.1.5 Carbonation shrinkage cracking Carbonation carbonation shrinkage cracks are free ions generated by water evaporation, causing shrinkage in the slurry. Carbonation is atmospheric CO2 conditions in the water reacts with the hydration product of CaCO3, alumina, silica and water free state, this part of the volume shrinkage of concrete caused by water evaporation (known as carbonation shrinkage), and its essence is the carbonate of the cement corrosion.General alkalinity of cement hydration products and the higher the concentration of CO2 in air and moderate humidity (50%), the more prone to carbonation. Therefore, this crack propagation in alternating wet and dry environment, and dry or water saturated environment, there is not easy; and because the crack of carbide precipitation will form a gel product, stop the CO2 into, it usually only occurs on the surface.Prevention of shrinkage cracks on the above can take the following measures:(a) mixed with superplasticizer, pumping agent to minimize water consumption; construction, cutting should not be too fast, and the vibration compacting.(b) For the prevention of early shrinkage cracking, in addition to strengthening the early conservation, the final setting of concrete should be conducted before the second wiping pressure, the material can be mixed with coagulant, and the appropriate use of high early strength and good water holding capacity of ordinary Portland cement; for the prevention of shrinkage cracks, can be appropriately extended curing time, the material should use fly ash in cement and other cement or shrinkage rate of small species.(c) minimize the amount of cement, coarse aggregate content increases, and limestone as the coarse aggregate should be chosen because of its superior shrinkage cracking resistance andesite and sandstone; should strictly control the sand content of aggregate, sand ratio should not be too big, should have good aggregate grading.(d) reduce their shrinkage cracking effective way is to use a low C3A content of cement, as C3A Portland cement clinker in the greatest chemical shrinkage reduction is a C2 S 3 times, C4AF of 5 times.(e) to prevent the carbonation shrinkage cracks key is to reduce the resultant alkalinity, good for fresh concrete wet water conservation, and the use of which the concrete structure to stay as dry as other corrosive gases in the high CO2 environment to good anti-corrosionmeasures.(f) pouring concrete trowel promptly after the straw with the wet or plastic film cover, the wind should be set up wind facility construction season.3.2 Crack Crack is the concrete difference in temperature, or seasonal temperature changes and the formation of excessiveIn the concrete pouring process, the cement hydration reaction will release a lot of heat (generally 502J per gram of cement can release heat), so that the internal temperature of concrete at a certain age there temperature peak, then declined.Since the slow cooling inside the concrete surface, fast heat, will form in the temperature difference between inside and outside, for the coordination of the temperature deformation, the concrete surface will have a tensile stress (ie thermal stress), when after more than make the cracking of concrete tensile strength. Such cracks are mostly cross-cutting and deep, severely reducing the overall stiffness of the structure; usually a few months after the end of the construction. In addition, concrete curing period, if the invasion by the cold will cause cracks in the concrete surface, but the lighter, smaller and harmful. Control of temperature cracks start mainly from the lower temperature, can take the following preventive measures:(a) the materials are advised to use fly ash or cement C3A and C3 S low-low-heat cement, to minimize the amount of cement can be mixed with superplasticizer; on the concrete, can be properly mixed with stones ; in the mixing water and aggregate were mixed and ice water cooling.(b) During the construction, the construction process should be reasonable arrangements to improve the construction process, such as pouring a large volume of concrete, pipes laid in concrete or block cyclic thermal stratification placement; improve the structure of constraints, such as a long structure to be set temperature, joints or back strip, when poured on bedrock, to shop 50 ~ 100 mm sand to remove the embedded solid role.(c) in the design, calculation of thermal stress is mainly good, according to temperature stress may have taken the appropriate structural measures, such as proper temperature reinforced configuration, shared concrete temperature stress.(d) In addition, still need to strengthen the concrete curing, good surface insulation measures (such as water conservation or covering wet straw, etc.), an appropriate extension of time for form removal to the slow cooling of the concrete surface; for the concrete, control ofentry mold temperature, and for temperature tracking, control the temperature difference between inside and outside of concrete in less than 25 ℃.3.3 Subsidence cracks Subsidence cracks is all part of the building after completion caused by differential settlement occurs, mostly cross-cutting, its location and settlement in the same direction. Eight-shaped wall buildings or herringbone cracks is a typical settlement pacted backfill without treatment, formation of soft layer containing the building was in use during the ground water (rain, water, etc.) long-term immersion and other factors will cause uneven settlement of the building to crack. The foundation also works in the new construction, if not make the necessary measures (such as the set of retaining walls, diaphragm walls) to prevent soil or groundwater intrusion instability will undermine the foundations of the adjacent old building capacity, resulting in building subsidence cracking. In concrete construction, due to insufficient template rigidity, support spacing is too large, too early form removal and other factors, there will be settlement cracks.Subsidence cracks are often severely affected structures, and endanger the durability of the structure, control measures to prevent its formation are:(a) in the basic design to ensure the bearing capacity of the bearing layer of uniform strength and foundation, in the story and the different parts of the junction of old and new buildings set the settlement joint.(b) In construction, the template should have sufficient strength and rigidity, and support reliable; Also, pay attention to the construction sequence, such as after the first high-rise low-rise, after the first of the main podium.(c) Geological Survey of pre-construction work to do, as far as possible a good choice of the bearing layer, after the completion of the foundation to avoid being soaked in rainwater.3.4 Other crack In addition to these cracks, the construction process in the structure will be various forms of construction cracks; in the structure will appear during use of different types of corrosion cracks.(1) Construction of crack Construction is due to cracks in the construction of improper operation or component itself, not the stiffness of such factors.If PC project, improper tension will form a component due to strength or strength not been made insufficient cracking; template project, if the concrete form removal or bonding with the template template upgrade easily to concrete crack; hoisting project, because of lateral reinforcement component lessstiffness of poor or incorrect lifting point on factors such as cracks. The key is to prevent such cracks in strict accordance with construction specifications, such as prestressed tension must be over 75% component intensity when, brushing between the template and concrete release agent, form removal, or sliding, the first uniform loose, and then slow detachment or upgrade.(2) corrosion cracks Corrosion cracking is due to structure a long period caused by corrosive liquid environment, which includes the corrosion of concrete and its reinforcement corrosion. Such cracks are often caused by the concrete is not dense, they are usually associated with shrinkage cracks, joint action of temperature cracks, leading to crack expanding and eventually weaken the structure of durability.Control measures are mainly doing the concrete surface and reinforcing steel corrosion protection, cracks should be repaired in time. In addition, if the existing concrete aggregate base active ingredient, cement high MgO content (> 5%) or UEA expansive agent such as too much content, alkali aggregate reaction will occur, or because of the hydration reaction of MgO to produce expansion of the gel, resulting in concrete expansion cracks, formed mostly mesh or irregular cracks.Such cracks tend to occur several years after completion of the structure, because the chemical reaction is extremely slow. The key to prevention is to eliminate or reduce the concrete in the presence of such substances.4. Treatment of crack Once the cracking of concrete structures should be identified on the basis of immediately take appropriate measures. At present, the commonly used methods of surface sealing repair, pressure grouting and filling blocking method.4.1 Surface sealing Less than 012mm for the width of the micro-cracks can be polymers of cement paste, permeability of flexible sealant or waterproofing agent brushing on the crack surface, to restore its water resistance and durability. The construction method is simple, but only superficial cracks.(1) process: the surface of the bristles and wash →embedding surface defect (available epoxy cement mortar or latex) →selection of coating compound.(2) construction elements;(a) As the coating is thin and should use strong adhesive material and not aging;(b) Cracks on the activities, should be greater flexibility in material elongation;(c) Tufu uniform, not a bubble.4.2 Pressure Grouting Width and depth greater than 013mm for the larger cracks can be chemical grouting material (such as polyurethane, epoxy or cement slurry) injected by pressure grouting equipment to deep cracks in order to restore structural integrity, water resistance and durability.(1) process:cutting grooves →laid slurry seal mouth →sealing →Check →→filling →preparation of slurry sealing →grouting quality control.(2) Construction of main points:(a) grouting materials should use strong adhesive resin can be irrigated with good material, usually used epoxy resin;(b) For large crack width is greater than 2mm, cement-like material can be used for active cracks should adopt the diluted epoxy resin or polyurethane;(c) chemical grouting pressure control in the 012 ~ 014MPa, pressure control of cement grouting in the 014 ~ 018MPa, increasing the pressure does not improve the filling rate, is not conducive to filling effect;(d) after grouting, when grout without leakage when the initial setting before grouting remove mouth (boxes, tubes).4.3 Complete blocking law Width greater than 015mm for the large cracks or cracks in steel corrosion can crack the concrete digged along the "U" type or "V" groove, and then filling them with repair materials to restore the water resistance, durability or part of the restoration of structural integrity .(1) process:cutting grooves →primary treatment (decontamination of concrete, steel rust) →brushing binder (epoxy grout) →→workmanship surface repair material handling.(2) Construction of main points:(a) Filling them with materials to choose depending on the particular epoxy resin, epoxy mortar, polymer cement mortar, PVC, clay or asphalt ointment;(b) For the corrosion cracks, the first completely rust on steel, and then cover rust paint. 5．SummaryConcrete Crack is a technical problem, long plagued engineering. In recent years, with high early strength cement is widely used as commercial concrete pumping vigorously promote the construction of the concrete strength grade increase, the emergence of mass concrete, to achieve results in the crack problem, while also more prominent, and even become Concretequality focus.The present concrete shrinkage cracks are mainly caused by deformation and deformation temperature, control of these cracks in addition to the general construction in the design and construction take appropriate measures, also need researchers have developed as quickly as possible to reduce shrinkage and hydration heat of cement efficient materials, which will crack the problem reduced to minimum.混凝土裂缝成因和防治措施问题的研究探讨摘要：目前混凝土裂缝问题倍受关注,本文在对混凝土裂缝进行分类的基础上,分析了不同裂缝的形成原因,并提出了裂缝防治的措施及处理方法。

roduction and prevention and cure of the crack of skyscraper Along with the speeding of town house construction step, not a few areas with small residences set up one after another, many inhabitants move continuously into the new residence, their quality to housing request is more and more high, particularly pay attention to very much to some cracks circumstances which sprinkle building plank to appear now, worry these cracks' aring end will cause insecurity trouble, but in succession to building quality direct the section hurl tell.Such as once the some city develop a company to set up 6 layers of floor residence 16 totally, constructing area about 100,000 square meters, the brick mixs structure, the beginning repairs, one steps 2 box off with the brick wall, each one's establishing a turn of beam together building plank is togetherwhole to sprinkle, the plank thick 100 mms, concrete mark number is C20, house long about with 80-90 ms, don't establish flexible sew, first floor is the 2.2 m garage layer, the C20 reinforcing bar cage of the foundation adoption infuses to note a stake.It's small area's turn to complete work in October,2003, finishing construction acceptance, didn't discover obvious crack, discover the building plank appears crack when the inhabitant repair, past jointly to quality direct the section hurl tell, through step to see on the spot, 16 houses all exist the depth different crack.The crack width is between the 0.2 mms mms-0.4ses, the great majority of the crack position is placed in plank four Capes, the dynasty sun is more obvious.Hence, the Superintendent office of quality concerned, sinking to decline quantity and inclination degree to carry on a reexamination to the house first, result all in allow the scope, again look into construction diagram paper to also match to request concerning the norm.Owing to above-mentioned circumstance, pass by hard analytical, the confirmation crack reason has the following what time:1. cause now main reason of sprinkling the plank crack is the constringency of concrete, the concrete is in the nature the hardening the process, because water evaporates continuously, but the physical volume gradual constringency, but the plank is on all sides to be subjected to a stipulation of, can't flex freely, so when the constringency of concrete cause to sprinkle knothole stipulation now should the dint exceed certain limit, certanly will cause to sprinkle plank to open crack now.And the crack part take place much at should the dint more concentrated Cape in the place-plank, but is mutually perpendicular with the Overcast angle line of wall2. construct too early on the cast-in-place board , add and carry on one's shoulder or back the crack caused. " norm of inspection of quality of structural construction of concrete " stipulates , before the concrete intensity reaches 1.2N/mm2, can't trample or install template and support on it . But developer , for race against time , catch up with progress , or concrete at , congeal and congeal stage after all for the first time still in water at the good cast-in-place board just, take up the post of purpose to trample, carry the material , concentrate on piling up fragment of brick , mortar , template ,etc.. Premature adding and is carried on one's shoulder or back, has caused the crack of cast-in-place board artificially.3. the crack which the temperature change causes. As everybody knows, the cement condenses and hardens fast at room temperature, the characteristic such as being great of heat of hydration, especially in summer, after the concrete is built, the release amount of the heat of hydration is great, the concrete is under the high temperature, can't get and water maintenance in time , and desiccate and shrink, make concrete take place dry to split , result in fracturing finally. Investigation find in the majority board corner crack in , tan by the sun towards the front directly the sun.4.the house is crossed too long to set up the essential expansion joint , is the reason which causes the crack too. The developer is in order to save the land, often take the length of the house into account , make the house whole too long, set up expansion joint either, because of lack essential expansion joint, freedom flexible degree in house reach or exceed should set up interval that expansion joint require , will present the crack too.5.the board is defeated by the muscle and sunk in the crack produced . In the course of constructing, because constructors operate barbarously, trample the reinforcing bar arbitrarily , cause and shoulder the muscle and sink, the antiabrasion layer is too big, reduce the sectional effective height of the board, make the bearing capacity of the board unable to reach the requirement of ones that design, thus cause the production of the crack of board.Effective height, make the bearing capacity of the board unable to reach the requirement of ones that design, thus cause the production of the crack of board. How to prevent and cure the production of the board crack of cast-in-place board, according to the construction experience for many years, offer some following prevention measures, suitable for consulting :1. Do well cast-in-place board maintain , work , guarantee concrete intensity , preventand cure important link that crack produce one of conscientiously. The norm stipulates , must cover and keep maintenance warm in 12 hours after the concrete is built at room temperature, ordinary cement is no less than 7 days, if the one that ignored to concrete watered maintenance, on one hand it reduce concrete intensity, on the other hand it make concrete to be in the course of hardening too late to supplement the moisture, therefore lack water and produce the crack in a large amount. So do a good job of watering maintenance of concrete , can already reduce the crack that temperature produces , can also reduce the crack that the concrete shrink and produce .2. cast-in-place board don't pass morning people , pile material , He Shi load , because concrete have a sclerosis course build ,, just have intensity; In this course , should maintain the concrete , can't exert any external force to the concrete . In a situation that the concrete has not had certain intensity yet , concentrate on , pile up construction material or prop up mould stand , rest on it, that brought the cast-in-place board is not intensity like this, but more cracks. So, must make sure that just allow to trample or install template and support on it after the concrete intensity reaches 1.2N/mm2.3. shoulder thickness of antiabrasion layer of the muscle the strict control panel . Cast-in-place board shoulder muscle put , on board , have roof beam according to designing requirement through generally put on reinforcing bar of roof beam or stay with reinforcing bar lashing of roof beam cut off , For control good to shoulder muscle antiabrasion layer thickness , must adopt φ10 - φ14 reinforcing bar horse stool, vertical-horizontal interval 800mm come fixed position to shoulder muscle from side to side, and with electric welding horse with shoulder muscle weld firm stool, make horse to be stool while the concrete builds non-wiping, guarantee , shoulder muscle sink, control , shoulder muscle thickness of antiabrasion layer effectively , make board shoulder muscle antiabrasion layer cross thick producing cracking.4. control good sand , stone in a foot-path and mud content strictly. The thick sand in the cast-in-place board should be selected for use, a stone of foot-path between 0.25-0.5mm, the mud content of grit can't exceed 1% . Sand,, stone grains of foot-path careful and too light, mud content too big, will reduce concrete intensity, will make the concrete produce the crack finally.5. dispose certain amounts of angle muscles in four corners of the board , radiate themuscle . Take place in board corner phenomenon this more to cast-in-place board crack, corner set up all around in boardThe length radiates the muscle for about 1800mm, so as to meet demands of angle stress of the board, the stress sphere of action of making the cast-in-place board produce the crack conforms with radiation muscle, thus change and control the production of the crack effectivelyforced concrete structure reinforced with an overviewRein Since the reform and opening up, with the national economy's rapid and sustained development of a reinforced concrete structure built, reinforced with the development of technology has been great. Therefore, to promote the use of advanced technology reinforced connecting to improve project quality and speed up the pace of construction, improve labor productivity, reduce costs, and is of great significance.Reinforced steel bars connecting technologies can be divided into two broad categories linking welding machinery and steel. There are six types of welding steel welding methods, and some apply to the prefabricated plant, and some apply to the construction site, some of both apply. There are three types of machinery commonly used reinforcement linking method primarily applicable to the construction site. Ways has its own characteristics and different application, and in the continuous development and improvement. In actual production, should be based on specific conditions of work, working environment and technical requirements, the choice of suitable methods to achieve the best overall efficiency.1.1 radial squeeze linkWill be a steel sleeve in two sets to the highly-reinforced Department with superhigh pressure hydraulic equipment (squeeze tongs) along steel sleeve radial squeeze steel casing, in squeezing out tongs squeeze pressure role of a steel sleeve plasticity deformation closely integrated with reinforced through reinforced steel sleeve and Wang Liang's Position will be two solid steel bars linkedCharacteristic: Connect intensity to be high, performance reliable, can bear high stress draw and pigeonhole the load and tired load repeatedly.Easy and simple to handle, construction fast, save energy and material, comprehensive economy profitable, this method has been already a large amount of application in the project.Applicable scope : Suitable for Ⅱ , Ⅲ , Ⅳ grade reinforcing bar (including welding bad reinforcing bar ) with ribbing of φ18- 50mm, connection between the same diameter or different diameters reinforcing bar .1.2must squeeze linkExtruders used in the covers, reinforced axis along the cold metal sleeve squeeze dedicated to insert sleeve Lane two hot rolling steel drums into a highly integrated mechanical linking methods.Characteristic: Easy to operate and joining fast and not having flame homework , can construct for 24 hours , save a large number of reinforcing bars and energy.Applicable scope : Suitable for , set up according to first and second class antidetonation requirement -proof armored concrete structure φⅡ , Ⅲ grade reinforcing bar with ribbing of hot rolling of 20- 32mm join and construct live.1.3 cone thread connectingUsing cone thread to bear pulled, pressed both effort and self-locking nature, undergo good principles will be reinforced by linking into cone-processing thread at the moment the value of integration into the joints connecting steel bars.Characteristic: Simple , all right preparatory cut of the craft , connecting fast, concentricity is good, have pattern person who restrain from advantage reinforcing bar carbon content.Applicable scope : Suitable for the concrete structure of the industry , civil building and general structures, reinforcing bar diameter is for φfor the the 16- 40mm one Ⅱ , Ⅲgrade verticality, it is the oblique to or reinforcing bars horizontal join construct live.These are now commonly used to connect steel synthesis methods, which links technology in the United States, Britain, Japan and other countries are widely used. There are different ways to connect their different characteristics and scope of the actual construction of production depending on the specific project choose a suitable method of connecting to achieve both energy conservation and saving time limit for a project ends.References1.construction manual write the group. Construction manual. Beijing: China Construction Industry Press, 1992.2.JGJ107-96 reinforcing bar machinery connects the common technical regulation 3 GB 1499-91 The armored concrete uses the reinforcing bar.3.GB with ribbing of hot rolling 13013-91 The armored concrete uses the round reinforcing bar of hot calendaring.现浇楼板裂缝的产生与防治随着城市住宅建设步伐的加快，不少住宅小区相继建成，许多住户陆续搬进新居，他们对住房的质量要求越来越高，尤其对一些现浇楼板出现的裂缝情况非常关注，担心这些裂缝最终会引发不安全事故，而纷纷向建筑质量监督部门投诉。

混凝土裂缝论文中英文资料对照外文翻译文献综述Causes and control measures of concrete cracks study the problemKeywords: Causes prevention of concrete cracksAbstract: At present, paid close attention to the problem of concrete cracks, this crack in the concrete on the basis of classification, analysis of the causes of different cracks, and proposed measures to crack prevention and treatment.1.IntroductionIs the maximum amount of concrete as a building material, widely used in industrial and civil construction, agriculture and forestry with urban construction, water conservancy works in the harbor. However, many concrete structures occurs during the construction and use of different degrees and different forms of fracture. This not only affects the appearance of the building, but also endanger the normal use of buildings and structures durability.Therefore, the cracks become people concerns. In recent years, with the ready-mixed concrete and vigorously promote the use and structure become increasingly large, complex, making the problem even more prominent.However, cracks in concrete structures is a fairly common phenomenon, large number of engineering practice and modern science on the concrete strength of micro studies show that the structures of the crack is inevitable, which is a property of the material. Therefore, the scientific treatment of cracks in the crack problem is to classify on the basis, adopt effective measures to harmful levels of crack control to the extent permitted. This concrete structure will cause cracks in common, control measures and the repair method to analyze some light.2.Classification of concrete cracks2.1 Divided by Crack According to the causes of concrete cracks, structural cracks and can be divided into two major categories of non-structural cracks.(1) Structural cracks Caused by a variety of external loads cracks, also called load cracks. It includes the external loads caused by the direct stress cracks and the structure under external loads caused by secondary stress cracks.(2) Non-structural cracks Deformation caused by the change from a variety of cracks. It includes temperature, shrinkage and swelling caused by factors such as differential settlement cracks. Such cracks in the structure when the deformation is restricted due to the stress caused. Research data from abroad and a large number of engineering practice, non-structural cracks in the works in the majority, about 80%, which led to shrinkage cracks.2.2Divided by the time the cracks(1)Cracks during construction Including plastic shrinkage cracks, settlement shrinkage cracking, drying shrinkage cracks, shrinkage cracks itself, the temperature cracks, the cracks were improper construction operations, the role of early frost, and some irregular cracks caused by cracks.(2)Use of crack during Including the expansion of steel corrosion cracks generated, salt and acid erosion type liquid medium caused by cracks, the cracks caused by freezing and thawing, alkali aggregate reaction, and cracks caused by cyclic loading cumulative damage caused by cracks.2.3Classification of fractured by cracks in the shape of the shape can be divided by:(1)Longitudinal cracks parallel to the bottom component, the distribution along tendons, mainly caused by the role of steel corrosion(2)Transverse cracks perpendicular to the bottom component mainly by the loading, temperature effects caused(3)Shear cracks due to displacement caused by vertical load or vibration(4)Diagonal cracks eight shaped or herringbone cracks, common in the wall of concrete beams, mainly due to the uneven foundation settlement, and thermal effects caused by(5)X-shaped cracks common in the framework of beams, columns and walls on the ends, due to the impact effect, or moment loads caused by earthquake(6)All kinds of irregular cracks such as repeated freezing and thawing, or fires caused by cracksIn addition, concrete mixing and transport time for long cracks due to mesh, squareappears floor slab or plate surface radial cracks appear in the cross cracks and so on.2.4 The development of the state divided by cracksAccording to fracture the movement in which the state and development trends, can be divided into the following categories:(1)Stable crack This crack does not affect the persistence of applications, including two types.One is in motion the process of self-healing of fractures could be common in a number of new water projects, this is because the crack of cement particles in the leakage of water further compounds the process, precipitate Ca (OH) 2 crystal and part of the Ca ( OH) 2 has dissolved in the water with CO2 carbonation reaction to form CaCO3 crystallization occurs, both the formation of cracks in the gel material will be glued closed, and thus stop the leakage, cracks to heal. The other is in a stable movement of the cracks, such as the periodic load generated by the cyclical expansion and closure of cracks.(2)Unstable crack This will result in instability of crack extension, affecting the sustainable use of structures, should be considered part of its expansion, to take corresponding measures.3.Causes of cracks in concrete and control measures3.1 Shrinkage cracks Shrinkage cracks are caused by the humidity, it accounts for non-structural cracks in concrete in the main part. We know that concrete is a cement as the main cementing material to natural sand, stone aggregate mixing water, after casting molding, hardens and the formation of artificial stone.In the construction, in order to ensure its workability, often adding cement hydration than water needed for 4 to 5 times more water. More of these water to free state exists, and the gradual evaporation of the hardening process, resulting in the formation of large pores inside the concrete, voids or holes, resulting in volume shrinkage of concrete. In addition, the hardening process of concrete hydration and carbonation of concrete volume will lead to shrinkage. According to the experimental determination of the ultimate shrinkage of concrete is about 0104% ~ 0106%.Shows that shrinkage is the inherent physical properties of concrete, in general, the larger water-cement ratio, the higher the concrete strength, aggregate less, the higher the temperature, surface water loss is larger, the larger the value of its contract, the more easily shrinkage cracks. According to the formation of shrinkage cracks and formation mechanism of the time, works in the common shrinkage cracksare mainly plastic shrinkage cracks, settlement shrinkage cracking and drying shrinkage cracks in three categories, in addition to their contract (chemical shrinkage) cracks and carbonation shrinkage cracks.3.1.1Plastic shrinkage cracks Plastic shrinkage cracks in concrete plastic stage, before the final set. The cause of this is concrete paste and quickly evaporating water flow to the surface, with the increase in water loss, capillary negative pressure generated by contraction of the concrete surface of the drastic volume shrinkage. Strength of concrete at a time has not yet formed, which resulted in cracking of the concrete surface.This multi-cracks in dry weather, hot and windy, the fracture shallow, intermediate width, both ends of the fine, of different lengths, and disconnected.3.1.2 Settlement shrinkage cracking Settlement shrinkage cracks in concrete pouring about half an hour after the occurrence and hardening stops. The cause of this is occurring after the slurry in the Pouring uneven sink, sinking of coarse aggregate, cement grout float, when the settlement was inhibited (such as steel or embedded parts of the block) is due to shearing and cracking of the concrete. In addition, floating in the plasma layer formed on the surface will be a result of bleeding and cracking.This multi-cracks in the concrete surface, and pass along the long direction of the reinforcement, or the stirrups the distribution width of both ends of the narrow middle, is a common early cracks, especially in the pump construction is more common.3.1.3 Drying shrinkage cracks Drying shrinkage cracks in the concrete curing only appeared after completion. Its formation was mainly due to the concrete to harden, the water evaporation caused by shrinkage of the concrete surface, when the shrinkage deformation of concrete by internal constraint, have a greater tensile stress to crack the concrete surface is pulled.Shrinkage cracks on the surface generally produces very shallow location, multi-component along the short direction of distribution, were parallel, linear, or mesh, can be severe throughout the member section.3.1.4 Self-shrinkage cracks Shrinkage cracks itself has nothing to do with the outside humidity, but because of the hydration reaction of cement clinker in the process, the reaction resultant of the average density of smaller volume shrinkage caused by system (called chemical shrinkage) due. Mainly due to hydration products of free water into a part of it39;s specific volume reduced by 1 / 4 (ie 0125cm3Pg).Therefore, the chemical shrinkage of the sizeof the reduction depends on the chemical combination of cement hydration products in the amount of water.3.1.5 Carbonation shrinkage cracking Carbonation carbonation shrinkage cracks are free ions generated by water evaporation, causing shrinkage in the slurry. Carbonation is atmospheric CO2 conditions in the water reacts with the hydration product of CaCO3, alumina, silica and water free state, this part of the volume shrinkage of concrete caused by water evaporation (known as carbonation shrinkage), and its essence is the carbonate of the cement corrosion.General alkalinity of cement hydration products and the higher the concentration of CO2 in air and moderate humidity (50%), the more prone to carbonation. Therefore, this crack propagation in alternating wet and dry environment, and dry or water saturated environment, there is not easy; and because the crack of carbide precipitation will form a gel product, stop the CO2 into, it usually only occurs on the surface.Prevention of shrinkage cracks on the above can take the following measures:(a) mixed with superplasticizer, pumping agent to minimize water consumption; construction, cutting should not be too fast, and the vibration compacting.(b) For the prevention of early shrinkage cracking, in addition to strengthening the early conservation, the final setting of concrete should be conducted before the second wiping pressure, the material can be mixed with coagulant, and the appropriate use of high early strength and good water holding capacity of ordinary Portland cement; for the prevention of shrinkage cracks, can be appropriately extended curing time, the material should use fly ash in cement and other cement or shrinkage rate of small species.(c) minimize the amount of cement, coarse aggregate content increases, and limestone as the coarse aggregate should be chosen because of its superior shrinkage cracking resistance andesite and sandstone; should strictly control the sand content of aggregate, sand ratio should not be too big, should have good aggregate grading.(d) reduce their shrinkage cracking effective way is to use a low C3A content of cement, as C3A Portland cement clinker in the greatest chemical shrinkage reduction is a C2 S 3 times, C4AF of 5 times.(e) to prevent the carbonation shrinkage cracks key is to reduce the resultant alkalinity, good for fresh concrete wet water conservation, and the use of which the concrete structure to stay as dry as other corrosive gases in the high CO2 environment to good anti-corrosionmeasures.(f) pouring concrete trowel promptly after the straw with the wet or plastic film cover, the wind should be set up wind facility construction season.3.2 Crack Crack is the concrete difference in temperature, or seasonal temperature changes and the formation of excessiveIn the concrete pouring process, the cement hydration reaction will release a lot of heat (generally 502J per gram of cement can release heat), so that the internal temperature of concrete at a certain age there temperature peak, then declined.Since the slow cooling inside the concrete surface, fast heat, will form in the temperature difference between inside and outside, for the coordination of the temperature deformation, the concrete surface will have a tensile stress (ie thermal stress), when after more than make the cracking of concrete tensile strength. Such cracks are mostly cross-cutting and deep, severely reducing the overall stiffness of the structure; usually a few months after the end of the construction. In addition, concrete curing period, if the invasion by the cold will cause cracks in the concrete surface, but the lighter, smaller and harmful. Control of temperature cracks start mainly from the lower temperature, can take the following preventive measures:(a) the materials are advised to use fly ash or cement C3A and C3 S low-low-heat cement, to minimize the amount of cement can be mixed with superplasticizer; on the concrete, can be properly mixed with stones ; in the mixing water and aggregate were mixed and ice water cooling.(b) During the construction, the construction process should be reasonable arrangements to improve the construction process, such as pouring a large volume of concrete, pipes laid in concrete or block cyclic thermal stratification placement; improve the structure of constraints, such as a long structure to be set temperature, joints or back strip, when poured on bedrock, to shop 50 ~ 100 mm sand to remove the embedded solid role.(c) in the design, calculation of thermal stress is mainly good, according to temperature stress may have taken the appropriate structural measures, such as proper temperature reinforced configuration, shared concrete temperature stress.(d) In addition, still need to strengthen the concrete curing, good surface insulation measures (such as water conservation or covering wet straw, etc.), an appropriate extension of time for form removal to the slow cooling of the concrete surface; for the concrete, control ofentry mold temperature, and for temperature tracking, control the temperature difference between inside and outside of concrete in less than 25 ℃.3.3 Subsidence cracks Subsidence cracks is all part of the building after completion caused by differential settlement occurs, mostly cross-cutting, its location and settlement in the same direction. Eight-shaped wall buildings or herringbone cracks is a typical settlement pacted backfill without treatment, formation of soft layer containing the building was in use during the ground water (rain, water, etc.) long-term immersion and other factors will cause uneven settlement of the building to crack. The foundation also works in the new construction, if not make the necessary measures (such as the set of retaining walls, diaphragm walls) to prevent soil or groundwater intrusion instability will undermine the foundations of the adjacent old building capacity, resulting in building subsidence cracking. In concrete construction, due to insufficient template rigidity, support spacing is too large, too early form removal and other factors, there will be settlement cracks.Subsidence cracks are often severely affected structures, and endanger the durability of the structure, control measures to prevent its formation are:(a) in the basic design to ensure the bearing capacity of the bearing layer of uniform strength and foundation, in the story and the different parts of the junction of old and new buildings set the settlement joint.(b) In construction, the template should have sufficient strength and rigidity, and support reliable; Also, pay attention to the construction sequence, such as after the first high-rise low-rise, after the first of the main podium.(c) Geological Survey of pre-construction work to do, as far as possible a good choice of the bearing layer, after the completion of the foundation to avoid being soaked in rainwater.3.4 Other crack In addition to these cracks, the construction process in the structure will be various forms of construction cracks; in the structure will appear during use of different types of corrosion cracks.(1) Construction of crack Construction is due to cracks in the construction of improper operation or component itself, not the stiffness of such factors.If PC project, improper tension will form a component due to strength or strength not been made insufficient cracking; template project, if the concrete form removal or bonding with the template template upgrade easily to concrete crack; hoisting project, because of lateral reinforcement component lessstiffness of poor or incorrect lifting point on factors such as cracks. The key is to prevent such cracks in strict accordance with construction specifications, such as prestressed tension must be over 75% component intensity when, brushing between the template and concrete release agent, form removal, or sliding, the first uniform loose, and then slow detachment or upgrade.(2) corrosion cracks Corrosion cracking is due to structure a long period caused by corrosive liquid environment, which includes the corrosion of concrete and its reinforcement corrosion. Such cracks are often caused by the concrete is not dense, they are usually associated with shrinkage cracks, joint action of temperature cracks, leading to crack expanding and eventually weaken the structure of durability.Control measures are mainly doing the concrete surface and reinforcing steel corrosion protection, cracks should be repaired in time. In addition, if the existing concrete aggregate base active ingredient, cement high MgO content (> 5%) or UEA expansive agent such as too much content, alkali aggregate reaction will occur, or because of the hydration reaction of MgO to produce expansion of the gel, resulting in concrete expansion cracks, formed mostly mesh or irregular cracks.Such cracks tend to occur several years after completion of the structure, because the chemical reaction is extremely slow. The key to prevention is to eliminate or reduce the concrete in the presence of such substances.4. Treatment of crack Once the cracking of concrete structures should be identified on the basis of immediately take appropriate measures. At present, the commonly used methods of surface sealing repair, pressure grouting and filling blocking method.4.1 Surface sealing Less than 012mm for the width of the micro-cracks can be polymers of cement paste, permeability of flexible sealant or waterproofing agent brushing on the crack surface, to restore its water resistance and durability. The construction method is simple, but only superficial cracks.(1) process: the surface of the bristles and wash →embedding surface defect (available epoxy cement mortar or latex) →selection of coating compound.(2) construction elements;(a) As the coating is thin and should use strong adhesive material and not aging;(b) Cracks on the activities, should be greater flexibility in material elongation;(c) Tufu uniform, not a bubble.4.2 Pressure Grouting Width and depth greater than 013mm for the larger cracks can be chemical grouting material (such as polyurethane, epoxy or cement slurry) injected by pressure grouting equipment to deep cracks in order to restore structural integrity, water resistance and durability.(1) process:cutting grooves →laid slurry seal mouth →sealing →Check →→filling →preparation of slurry sealing →grouting quality control.(2) Construction of main points:(a) grouting materials should use strong adhesive resin can be irrigated with good material, usually used epoxy resin;(b) For large crack width is greater than 2mm, cement-like material can be used for active cracks should adopt the diluted epoxy resin or polyurethane;(c) chemical grouting pressure control in the 012 ~ 014MPa, pressure control of cement grouting in the 014 ~ 018MPa, increasing the pressure does not improve the filling rate, is not conducive to filling effect;(d) after grouting, when grout without leakage when the initial setting before grouting remove mouth (boxes, tubes).4.3 Complete blocking law Width greater than 015mm for the large cracks or cracks in steel corrosion can crack the concrete digged along the "U" type or "V" groove, and then filling them with repair materials to restore the water resistance, durability or part of the restoration of structural integrity .(1) process:cutting grooves →primary treatment (decontamination of concrete, steel rust) →brushing binder (epoxy grout) →→workmanship surface repair material handling.(2) Construction of main points:(a) Filling them with materials to choose depending on the particular epoxy resin, epoxy mortar, polymer cement mortar, PVC, clay or asphalt ointment;(b) For the corrosion cracks, the first completely rust on steel, and then cover rust paint. 5．SummaryConcrete Crack is a technical problem, long plagued engineering. In recent years, with high early strength cement is widely used as commercial concrete pumping vigorously promote the construction of the concrete strength grade increase, the emergence of mass concrete, to achieve results in the crack problem, while also more prominent, and even become Concretequality focus.The present concrete shrinkage cracks are mainly caused by deformation and deformation temperature, control of these cracks in addition to the general construction in the design and construction take appropriate measures, also need researchers have developed as quickly as possible to reduce shrinkage and hydration heat of cement efficient materials, which will crack the problem reduced to minimum.混凝土裂缝成因和防治措施问题的研究探讨摘要：目前混凝土裂缝问题倍受关注,本文在对混凝土裂缝进行分类的基础上,分析了不同裂缝的形成原因,并提出了裂缝防治的措施及处理方法。

英文原文：Building construction concrete crack ofprevention and processingAbstractThe crack problem of concrete is a widespread existence but again difficult in solve of engineering actual problem， this text carried on a study analysis to a little bit familiar crack problem in the concrete engineering， and aim at concrete the circumstance put forward some prevention， processing measure。

Keyword:Concrete crack prevention processing ForewordConcrete's is 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。

建筑施工混凝土裂缝的预防与处理毕业论文外文翻译Prevention and Treatment of Concrete Cracks in ConstructionAbstract：Concrete has been widely used in construction because of its good durability and high structural strength. However, concrete is prone to cracks during construction, which can seriously affect the performance and service life of buildings or structures. Therefore, it is necessary to take preventive measures to reduce the occurrence of cracks in concrete. This paper summarizes the causes of concrete cracks and the measures to prevent and treat concrete cracks in construction, aiming at providing a reference for concrete construction engineering.Keywords：concrete; cracks; prevention; treatment1 IntroductionConcrete has been widely used in the construction industry due to its good durability, high structural strength and other advantages. However, concrete is also prone to cracks during construction, which can seriously affect the performance and service life of buildings or structures. Therefore, it is necessary to take preventive measures to reduce the occurrence of cracks in concrete.2 Causes of Concrete Cracks2.1 Internal Causes2.1.1 Material QualityThe quality of the concrete material directly affects the strength and durability of the concrete structure. If the raw materials are not properly prepared or mixed, the quality of the concrete will be affected, leading to cracks in the structure.2.1.2 Technical FactorsDuring the pouring and curing processes of concrete, technical factors such as the amount of water added, the mixing time, the compactness of the concrete, the curing conditions and the temperature control, etc., will affect the strength and durability of the concrete structure.2.2 External Causes2.2.1 Environmental FactorsDuring the construction of concrete structures, environmental factors such as temperature, humidity, wind, rain and snow, etc. can have an impact on the strength and durability of the concrete structure. For example, low temperatures can cause the concrete to freeze and form cracks, while high temperatures can cause the concrete to expand and crack.2.2.2 Load FactorsLoad factors refer to the external forces that act on the concrete structure, such as weight load, wind load, earthquake load, etc. If the load is too large or unevenly distributed, it can cause cracks or deformation in the concrete structure.3 Prevention of Concrete Cracks3.1 Ensure Good Construction QualityThe construction quality of concrete structures directly affects the occurrence of cracks. Therefore, in the construction process, it is necessary to strictly follow the design and construction specifications, and pay attention to the quality control of all aspects of the construction.3.2 Reasonably Design the StructureReasonable structure design can effectively prevent cracks in concrete. The design of the construction joints, expansion joints and contraction joints should be reasonably determined according to the characteristics of the structure and environmental factors to prevent the occurrence of cracks caused by temperature changes or load factors.3.3 Strengthen the Construction JointsStrengthening the construction joints can effectively prevent the occurrence of cracks in the joints between the old and new concrete structures, and between the precast concrete components and the cast-in-place concrete structures. Reinforcement measures can be taken to ensure the continuity and uniformity of the joints.3.4 Control the Temperature and HumidityControl of the temperature and humidity during the pouring and curing of the concrete is also an important measure to prevent the occurrence of cracks. The temperature and humidity must be controlled within a reasonable range to ensure the normal hydration and curing of the concrete.4 Treatment of Concrete Cracks4.1 Grouting and SealingGrouting and sealing are common methods for treating cracks in concrete structures. The method is to inject a certain amount of grouting material into the cracks to fill the gaps, and then use sealing materials to seal the surface of the cracks to prevent the intrusion of water and other substances.4.2 Patching and ReinforcementFor concrete cracks caused by insufficient structural strength or uneven load distribution, patching and reinforcement methods can be used. The method is to apply a new layer of concrete or repair mortar to the surface of the cracks to increase the strength and load-bearing capacity of the structure.4.3 ReplacementFor severe cracks or damaged concrete structures, replacement is often the only way to solve the problem. The method is to completely remove the damaged parts and replace them with new concrete or precast components.5 ConclusionIn summary, concrete cracks are a common problem in the construction industry, but they can be prevented and treated through effective measures. In the construction process, attention should be paid to the quality of the concrete material, the technical factors, and the environmental and load conditions. In addition, reasonable structure design and strengthening of the construction joints, as well as control of the temperature and humidity, should be considered to prevent the occurrence of cracks. For existing cracks, grouting and sealing, patching and reinforcement, or replacement methods can be used to effectively repair the damaged structures.。

混凝土裂缝的产生与预防毕业论文外文翻译The production and prevention of concrete cracksAbstract：This paper discusses the reasons for the production of concrete cracks and the preventive measures for cracking in the construction process. In the production process of concrete, it is influenced by many factors, such as temperature, humidity, mix materials, construction technology, etc., which may lead to the formation of cracks in the concrete structure. This article analyzes the causes of concrete cracking from various aspects such as raw materials, mixing, placing, and curing, and puts forward corresponding preventive measures. The purpose of this paper is to provide a reference for the prevention of concrete cracks in the construction process and to improve the quality of the engineering.Keywords：concrete, crack, production, prevention1. IntroductionConcrete is one of the important building materials in modern engineering, and it is widely used in various types of buildings, road construction, and infrastructure projects. The quality of concrete is directly related to the safety and durability of the structure, and the requirements for the quality of the concrete become higher and higher as the engineering technology advances. In order to improve the quality of the concrete, it is necessary to control the factors that affect the production and use of the concrete, especially the phenomenon of concrete cracking.The production and use of concrete are influenced by various factors, such as the raw materials, mixing, placing, and curing, which may cause concrete cracking. Therefore, it is necessary to analyze the factors that cause concrete cracking and adopt corresponding preventive measures in the construction process to prevent the occurrence of cracks in the concrete structure.2. The reasons for the production of concrete cracks2.1 The impact of raw materialsThe quality of raw materials, such as cement, aggregate, admixture and water, has a direct impact on the properties of concrete, and the quality of concrete isdirectly related to the occurrence of cracks. In the production process, if the quality of the raw materials is not good, it will affect the strength, elasticity, and crack resistance of the concrete.For example, if the water-cement ratio of the concrete is too high or the particle size of the aggregate is uneven, it will cause the internal pores to increase and the distribution to be uneven, which will reduce the compactness of the concrete, thus causing cracks in the hardened concrete. If the quality of the admixture is not good, it will affect the workability and cohesiveness of the concrete, and affect the fluidity of the concrete, which may cause cracks in the concrete.2.2 The impact of mixingMixing is a key process in the production of concrete, and the quality of mixing directly affects the properties of concrete. If the mixing is improper, it will cause the concrete to have uneven density, segregation, bleeding, and other phenomena, and the hardened concrete will be prone to cracking.For example, if the mixing time is too long, it will cause the concrete to segregate, the coarse aggregate to sink, and the mortar to float, which will cause the internal stress of the concrete to increase and crack under the action of external force. If the mixing speed is too fast, it will cause the air entrainment rate of the concrete to increase, which will reduce the density of the concrete and reduce the strength of the concrete.2.3 The impact of placingPlacing is the process of conveying concrete to the site and properly placing it in the formwork. If the placing operation is not standardized or the environmental conditions are not suitable, it will cause the concrete to be unevenly stressed and result in cracks in the structure.For example, if the pouring time is too long, the concrete will lose workability and result in poor compaction, which will lead to the occurrence of segregation and bleeding. If the temperature of the environment is too high or too low, it will affect the hydration of the cement and cause cracks in the hardened concrete.2.4 The impact of curingCuring is the process of keeping the concrete wet and at a suitable temperature after placing, in order to promote the continuous hydration of cement and the growth of the strength of the concrete. If the curing is not timely and sufficient or the curing conditions are not properly controlled, it will cause the concrete to lose moisture and strength, and lead to the occurrence of cracks in the concrete.For example, if the concrete is cured in a dry environment or exposed to sunlight, it will cause the surface of the concrete to dry out quickly and shrink, thus leading to the occurrence of cracks in the hardened concrete. If the curing time is not long enough or the curing conditions are not controlled properly, it will cause the strength of the concrete to be insufficient, which will also cause cracks in the structure.3. Methods of preventing concrete cracks3.1 Improving the raw materialsIn the production process of concrete, attention should be paid to the quality of raw materials, and the proportion of different materials should be reasonable. The quality of the cement should be strictly controlled, and the particle size and grading of the aggregate should be uniform. The admixture should be properly selected and used to improve the workability and cohesiveness of the concrete.3.2 Improving the mixing processIn the process of mixing, the mixing time and mixing speed should be properly controlled, and the mixing should be uniform to ensure the quality of the concrete. The operation should be standardized to prevent segregation and bleeding, and measures should be taken to reduce the air entrainment rate, so as to increase the density of the concrete.3.3 Improving the placing processIn the process of placing, the pouring time should be appropriate, and the operation should be carried out smoothly to prevent segregation and bleeding. The temperature and humidity of the environment should be kept suitable, and the temperature of the concrete should be controlled to prevent the occurrence of shrinkage cracks.3.4 Improving the curing processIn the process of curing, the concrete should be kept moist and at a suitable temperature, and the curing time should be sufficient to ensure the strength of the concrete. The curing conditions should be properly controlled to prevent the surface of the concrete from drying out and causing shrinkage cracks.4. ConclusionIn the production and use of concrete, the phenomenon of concrete cracking cannot be completely avoided, but through the analysis of the causes of concrete cracking and the adoption of corresponding preventive measures, the occurrence of concrete cracking can be effectively reduced, and the quality of the engineering can be improved. Therefore, it is necessary to carry out scientific and standardized production and construction, control the factors that affect the production and properties of concrete, and prevent the occurrence of concrete cracking.。