外文翻译 - 分析了钢筋砼结构裂缝的成因和危害

广西科技大学2013 届毕业生毕业设计中英文翻译姓 名： 学 号： 班 别： 专 业： 学 院： 指导老师：广西*柳州2013 年 5 月 20 日T h e M et h od t o A n alyze and Deal w it h Cr evice of Rein f orcedAbstractIn t h is paper t he caus e of forat ion an d h arm of crevice in rein forced co ncrete structure are analyzed an d t h e met h ods t o deal wit h t he crack are dis cu ss ed . Through practical study o n engineering ex ample, several p rob lem s, t o which at tent ion should b e p aid in process o f construct in g an d treating w it h crevice, are solved and concluded in t he p aper.Key words: concrete; crevice; gro ut in g an d constructing摘 要分析了钢筋砼结构裂缝的成因和危害 性 , 讨论了 裂缝的处理方法。通过 工程实 例的应用研究, 总结了裂缝处理施工中应注意的几 个问题。关 键 词 : 混 凝 土 ; 裂 缝 ; 灌 浆 施 工Under normal circumstances, the reinforced concrete structure there are some cracks are inevitable, especially widely used in commercial concrete, using the method of adding various additives and superfine mineral admixture for high strength, high-flow pattern of the concrete,cracks of the concrete structure of the problem is more serious 1.The relevant specification for crack control by limiting the crack width of concrete structures. The concrete structure in the form of cracks and the causes are many and varied, scientific and rational method of crack treatment response to actual cracks in the analysis of the causes and dangers, and then take effective measures to crack the dangers of control in a certain extent permitted by . This regard, some analysis and discussion.1.Classification of a Concrete Structure Cracks and Criticality Analysis.1.1 Concrete Structure of the Causes of Cracks.Classification of the reinforced concrete structure cracks, the causes of cracks in this classification, lists the types of cracks in structural performance.1.1.1 Load Crack. Due to external loads caused by cracks known as load cracks, such cracks generally appear in the component forceAfter the stress bearing capacity is relatively weak parts. Divided into the main flexural cracks, tension cracks, compression cracks, distorted cracks, shear cracks and punching crack.1.1.2 The Role of Temperature Cracks. Sunshine temperature difference or cracks caused by the high temperature as the temperature of the role of cracks, such cracks generally appear in the housing top floor slab components and to produce high temperature heat source near the concrete components. In addition, the large volume concrete cracks due to the thermal effect of cement hydration also belong to the scope of temperature crack.1.1.3 Shrinkage Cracks. Cracks caused by contraction of the concrete is known as shrinkage cracks, early shrinkage cracks appear in the middle of the concrete surface after the concrete has hardened shrinkage cracks appear in the component. In recent years, the change prefabricated hollow board for the large number of Slab Slab shrinkage cracks (cracks wider and up and down through cracks in the plate cross or vertical board and the board diagonal of the four corners area), has become a new quality defects 2.1.1.4 The Deformation of Foundation Cracks.The foundation differential settlement and cracks of the concrete structure known as the deformation of foundation cracks. These cracks occurred mainly to ring beam to beam, plate-based backplanes and building the lower part of the settlement of mutations at the concrete beam at the top of the board corresponding part of the column.1.1.5 Disaster Cracks and Other. Concrete structures under fire, freezing and thawing, and steel corrosion, cracks generated by factors such as alkali-aggregate reaction is more common cracks, analysis and processing of such cracks has its particularity. 3.1.2 The Concrete Structural Cracks Hazard Analysis.Cracks in the concrete structure of the dangers in the following three aspects.1.2.1 Affect the Durability. Durability of concrete structures is the load-bearing structure. The design specifications of the concrete structure to allow the concrete structures with cracks, but there will be limitations on crack width. When the crack width of concrete structure exceeds a certain value, the environment, water, oxygen, carbon dioxide and chlorine ions penetrate through the cracks make steel corrosion within the concrete, and ultimately affect the structural carrying capacity. Cracks under different environmental conditions on the structural durability of the degree of harm. Especially in the open air, wet or harmful gases under the conditions of the concrete components, when the crack width 2 mm, depth over the protective layer thickness will cause the corrosion of reinforced concrete components.1.2.2 Affect the Structure of the Normal .Using of the cracks on the normal structure mainly refers to the impermeability and water resistance of the structure.1.2.3 Affect the Structural Safety of the Deformation .due to the lack of structural capacity and foundation cracks larger and will affect the safety of the structure. Especially cracks in the concrete compression, shear cracks and distortion cracks, these cracks will produce brittle failure of concrete structures, reinforcement measures should be timely.1.3 Crack Analysis and Processing Procedures and Principles.Cracks in the concrete structure for processing, we must first determine the nature of the cracks, and then select the cracks approach. The specific handling procedures and principles are as follows:The use of the survey of buildings.parts of cracks and crack width, depth, quantity and distribution.According to field investigations and test results, analyze the causes of cracks analyze the extent of the harm of the cracks in the concrete structure.determine fracture properties select the cracks approach.belonging to the load crack, the deformation of foundation cracks and has affected the structural safety of the cracks should first take structural reinforcement measures, and then determined after the reinforcement crack repair approach.When used to increase the cross-section method, paste steel or carbon fiber reinforced and Steel Reinforcement, these methods have the crack sealing treatment.By changing the load path reinforcement method or prestressed reinforcement, law and foundation reinforcement to deal with cracks in the surface closed. The temperature of shrinkage cracks and crack width smaller load crack, the deformation of foundation cracks, first of all distinguish between surface cracks and deep cracks. Surface cracks to surface sealing treatment method, deep cracks take the grouting method to repair. Deep cracks must still cracks or active cracks and stationary cracks is preferable to have a certain flexibility grouting material.2.Concrete Structures Crack Approach.2.1 Crack Treatment Methods and the Scope of Cracks Approach.There are three kinds of surface treatment, filling method and the grouting method.2.1.1 The Surface Treatment Method. Cracks in the surface of stucco cement mortar, brushing polymer cement paste and permeable waterproof materials in order to achieve the recovery of structural durability and impermeability. Mainly applied to the crack width is less than 2 mm, minor crack sealing treatment.2.1.2 Filling. Chiselled V shaped or trapezoidal groove along the cracks in the concrete surface and then layered pressure to wipe a variety of repair materials, the purpose of the closure of cracks, which V shaped groove for the general crack repair; trapezoidal groove is applicable to water seepage the repair of cracks. Applies to the small number, but the width of the larger (greater than 0 5 mm) cracks closed. Can be collected through the deeper cracks . Fill method will be closed cracks, then the construction of the grouting method.2.1.3 The Grouting Method. Method will put pressure on all types of resin grout, cement grout poured into the cracks in the curing, bonding to repair the cracks in the concrete structure. The grouting method is mainly applied to the crack width is greater than 0 2 mm crack repair process. Width between 2 mm 1. 0 mm, most of the cracks in the concrete structure of crack accident, the grouting method is the main fracture treatment.2.2 Grouting Construction Technology.Depending on the grouting materials, grouting method is divided into the chemical grouting method and inorganic materials, grouting method, the former materials used for epoxy resin and methacrylic acid esters, which is the class of the slurry.For a long time, because the cement grout particles, only for the crack width is greater than 1 0 mm crack repair. Chemical grouting material strong bond, irrigation performance, so the project the use of chemical grouting materials than cement grouting applications generally. However, due to the chemical grouting the high cost, pollution and other shortcomings, in recent years use on the project at home and abroad more and moreLimit the application of the modified cement grout has more and more. The grouting process and grouting equipment of the same chemical grouting methodEquipment, modified cement slurry poured into the width is greater than 0 5 mm and deeper cracks has become a commonly used technology.2.2.1 Epoxy Slurry Material.In recent years, a special variety of grouting resin epoxy of low viscosity, flexible epoxy, water emulsion epoxy and polyurethane resin, these resins have a small contraction, high flexibility, good toughness, adaptability, and the advantages of fine cracks ( 05 mm), wide cracks (1 mm), as well as mortar, concrete cracks the case for chemical grouting treatment, curing in a wet or dry environment. The lower the viscosity, the faster filling.(1) agent (matrix). The slurry of the main agent of epoxy resin, which is a polymer containing two or more epoxy gene compounds in general 4.(2) Other materials. In order to reduce the shrinkage of the epoxy grout, the choice of the reactive diluent - epichlorohydrin, and appropriate to add non-reactive diluent - acetone. Make epoxy slurry to a plasticized and curing functions can be added to the amount HJ plasticizers and two small fat. Polymerization, the molecular weight increases, the elastic and plastic, and impact toughness will be greatly enhanced 4.(3) preparation of the slurry. Epoxy resin system is one of the most commonly used adhesive system, you want to reach the pressure perfusion 0 and less than 5mm gap, the viscosity should be adjusted to below 200 the CP, so how to adjust the viscosity is the key issue of pouring glue. Commonly used diluent three categories - bran ketones, low molecular weight epoxy compounds, non-reactive diluent. The first two categories, known as reactive diluents, they can participate in the curing reaction, but the dilution of low efficiency and poor storage stability of bran ketones. 4）The general literature suggests that the diluent, such as aromatics, ketones and alcohols play a simple dilution effect in the curing of epoxy resin, after curing gradually evaporate. In fact, the carbonyl and hydroxyl compounds composed of diluents on some elements of the system or there is a certain reaction. No significant response to the hydroxyl-containing alcohols at room temperature with epoxy resin this can also be partially involved in the reaction but in the role of the amine curing agent, played the role of toughening. The active hydrogen on the hydroxyl significantly shorten the activation time to play a catalytic role of procoagulant. The other role is to reduce the surface tension, improve adhesive infiltration, absorption and leakage. Hydroxyl hydrophilic adhesive to quickly absorb the damage to the water film, adhesive curing in humid conditions.5) The physical and mechanical properties of the physical and mechanical properties of the slurry ratio of the epoxy grout is shown in Table 1.Note: The traditional ratio cited from Chemical Grouting ; concrete paste tensile strength refers to two parts of the concrete casting epoxy paste adhesive as a whole, the measured was anti- Tensile strength. It can be seen from Table 1, epoxy slurry has good physical and mechanical properties, shrinkage rate of 0% to 0.3%, the average shear strength of 34 M Pa, the average tensile strength of 5 M Pa. Adding the appropriate diluent and modifier of the epoxy grout the physical and mechanical properties of conventional epoxy grout 2-6 times, are higher than the tensile strength and shear strength of C35 concrete structure itself completely to meet the concrete structure reinforcement requirements. 2.2 .2 Methyl Methacrylate Class .Methyl methacrylate, low viscosity, surface tension is only about 30 percent of the water, so pouring more convenient, strong and proliferation. Practice has proved that for the width of the 0 0 5 mm around the crack repair and impervious to good effect. The repair of dry cracks in the curing strength and high bond strength than the concrete components, therefore, can fully restore the concrete integrity. Patch of water split Seam, you need to use the appropriate formula and process, in order to partially restore the integrity of the concrete and 2.2 3 Cement Grouting Material Cement grouting materials are mainly silica fume modified cement grout, the glial cement grouting material and ultra-fine cement grouting material. Physical and technical parameters of the ultra-fine cement grout as follows: Fine S 8 600 cm 2 / g, integrated particle size d 50 4 m, particles larger than 20 m are limited to less than 2% (ordinary 525 The fineness of the cement # S = 3 200 cm 2 / g). Pulp, water-cement ratio to take the W / C = 1 0, and its performance are shown in Table 2, the system out of the slurry to meet the perfusion crack width 0. 3 mm requirements. （表2）Note: The plastic viscosity; yield value; f d, f 7d, f 1 5d were serous in 3 days, 7 days, the 15-day bond strength 2.2 Grouting Technology and Construction Procedures. (1) The grouting process is as follows Crack survey cutting of V or U-shaped groove paste filling mouth leak testing closed cracks preparation of the pressure grouting of epoxy slurry Banding mouth the grouting end room temperature curing (3 days) delivery。(2) construction rules:Investigation of crack grouting crack width to be implemented: in the pre-construction to deal with, length toward the careful examination, and make the specific location of the mark.Crack clean-up: First, clean up of the cracks on both sides of the floating pulp, and then blow guns to the air compressor with high pressure air blow off the crackSewn inside the floating ash and floating objects, and the concrete surface with acetone to clean up.Set grout mouth.Grouting mouth set the direction of the crack cloth mouth, according to the principle of airflow Soars, grouting mouth should be arranged in the lower part of a nozzle arrangement for about 25 0 mm spacing in the upper packer, but each crack at least required layout grouting mouth of two or more (depending on the crack length). Grouting mouth fixed in general with 502 rubber grout mouth exports at the cracks, and press in the concrete surface to be cement let go. In addition, can also be used for epoxy mortar grout mouth paste it in the cracks.The crack closure of good cementing clay: brushing modulation in the cracks on both sides, and closure of existing cracks, paying particular attention to the bottom of the grouting mouth tightly closed, and to ensure the packer firmly affixed to the work surface. In addition, in the cracks on both sides of each leave a small hole in order to observe the full extent of the grouting solution. Is also conducive to the discharge of residual air in the cracks, the width of the clay closed 5 cm.Check the seal quality: sealed plastic curing (usually more than 12 h) to conduct leak testing and inspection. In a closed clay coated fertilizerSoap water, each grouting lips the high-pressure plastic tube connected to the air machine (line 22 banding) test gas, and carefully observe whether there are bubbles appear,Full internal grouting to determine cracks. If it is found to leak at the application of clay trap until no bubbles appear.Grouting: the deployment of good slurry grout into the barrel, tighten the grouting tube feed inlet to start the air compressor when the pressure within the air tank up to 4 M Pa, close the inlet valve, open the grouting tube grouting valve at the bottom, through the grouting nozzle, the slurry pressed into the cracks. When the slurry from the bottom slowly down to the top of the cracks on both sides of the upper holes for slurry emerge, the cracks in the slurry has been filled regulator for 2 min or so, and then gradually decompression to zero. Meanwhile, the butter applied to the grouting in the mouth hole, to prevent the slurry reflux. Veterinary syringes and high-pressure oil gun can also be used when the crack lighter pressure required for perfusion. But it must be to control the working pressure of about 0. 4 the MP a. Under this pressure, such as slurry to stop the flow of the upper part of the exhaust pipe slurry outflow, indicating that the slurry is already saturated.3. Engineering ExampleA multilayer frame structure workshop of the engineering construction in July, 1994,For five reinforced concrete frame structure across,For a layer of middle cross, span of 9 m, 7 m tall, and its neighbors on both sides of the cross for the second floor, outside the two for three layer across. Concrete design strength C20.In use process, use the unit found in the workshop across the midspan have obvious beam crack,The crack width is 0. 45 1. 5 m m between the, in the frame beams cross in have greater single vertical cracks, the crack surface total length up to 800 mm, close to the bottom of the roof.The study decided to crack first using epoxy resin slurry grouting for repair, grouting pressure is 0. 3-0. 5