建筑施工混凝土裂缝 毕业论文文献翻译.doc

building construction concrete crack abstractthe crack problem of concrete is a widespread existence but again difficult in solve of engineering actual problem, this text carried on a study analysis to a little bit familiar crack problem in the concrete engineering. keyword:concrete crack foreword concretes ising 1 kind is anticipate by the freestone bone, cement, water and other mixture but formation of the in addition material of quality brittleness not and all material.because the concrete construction transform with oneself, control etc. a series problem, harden model of in the concrete existence numerous tiny hole, spirit cave and tiny crack, is exactly because these beginning start blemish of existence just make the concrete present one some not and all the characteristic of quality.the tiny crack is a kind of harmless crack and accept concrete heavy, defend shen and a little bit other use function not a creation to endanger.but after the concrete be subjected to lotus carry, difference in temperature etc. function, tiny crack would continuously of expand with connect, end formation we can see without the aid of instruments of macro view the crack be also the crack that the concrete often say in the engineering. concrete crack creation of the reason be a lot of and have already transformed to cause of crack:such as temperature variety, constringency, inflation, the asymmetry sink to sink etc. reason cause of crack;have outside carry the crack that the function cause;protected environment not appropriate the crack etc. caused with chemical effect.want differentiation to treat in the actual engineering, workout a problem according to the actual circumstance. in the concrete engineering the familiar crack and the prevention 1.stem suo crack and prevention stem the suo crack much appear after the concrete protect be over of a period of time or concrete sprinkle to build to complete behind of around a week.in the cement syrup humidity of evaporate would creation stem suo, and this kind of constringency is cant negative.stem suo crack of the creation be main is because of concrete inside outside humidity evaporate degree dissimilarity but cause to transform dissimilarity of result:the concrete is subjected to exterior condition of influence, surface humidity loss lead quick, transform bigger, inner part degree of humidity variety smaller transform smaller, bigger surface stem the suo transform to be subjected to concrete inner part control, creation more big pull should dint but creation crack.the relative humidity is more low, cement syrup body stem suo more big, stem the suo crack be more easy creation.stem the suo crack is much surface parallel lines form or the net shallow thin crack, width many between 0.05-0.2 mm, the flat surface part much see in the big physical volume concrete and follow it more in thinner beam plank short to distribute.stem suo crack usually the anti- shen of influence concrete, cause the durable of the rust eclipse influence concrete of reinforcing bar, under the function of the water pressure dint would creation the water power split crack influence concrete of loading dint etc.concrete stem the suo be main with water ash of the concrete ratio, the dosage of the composition, cement of cement, gather to anticipate of the dosage of the property and dosage, in addition etc. relevant. 2.the su constringency crack and prevention su 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, cracks much presenting in the center breadth, both ends be in the centerthin and the length be different, with each other not coherent appearance.shorter crack general long 20-30 cm, the longer crack can reach to a 2-3 m, breadth 1-5 mm.it creation of main reason is:the concrete is eventually almost having no strength or strength before the ning very small, perhaps concrete just eventually ning but strength very hour, be subjected to heat or compare strong wind dint of influence, the concrete surface lose water to lead quick, result in in the capillary creation bigger negative press but make a concrete physical volume sharply constringency, but at this time the strength of concrete again cant 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. 3.sink to sink crack and prevention the creation which sink to sink crack is because of the structure foundation soil quality not and evenly, loose soft or return to fill soil dishonest or soak in water but result in the asymmetry sink to decline with the result that;perhaps because of template just degree shortage, the template propped up to once be apart from big or prop up bottom loose move etc. to cause, especially at winter, the template prop up at jelly soil up, jelly the soil turn jelly empress creation asymmetry to sink to decline and cause concrete structure creation crack.this kind crack many is deep enter or pierce through sex crack, it alignment have something to do with sinking to sink a circumstance, general follow with ground perpendicular or present 30 s-45 cape direction development, bigger sink to sink crack, usually have certain of wrong, crack width usually with sink to decline quantity direct proportion relation.crack width under the influence of temperature variety smaller.the foundation after transform stability sink to sink crack also basic tend in stability. 4.temperature crack and prevention temperature crack much the occurrence is in big surface or difference in temperature variety of the physical volume concrete compare the earth area of the concrete structure.concrete after sprinkling to build, in the hardening the process, cement water turn a creation a great deal of of water turn hot, .(be the cement dosage is in the 350-550 kg/m 3, each sign square the rice concrete will release a calories of 17500-27500 kj and make concrete internal thus the temperature rise to reach to 70 or so even higher)because the physical volume of concrete be more big, a great deal of of water turn hot accumulate at the concrete inner part but not easy send forth, cause inner part the temperature hoick, but the concrete surface spread hot more quick, so formation inside outside of bigger difference in temperature, the bigger difference in temperature result in inner part and exterior hot the degree of the bulge cold suo dissimilarity, make concrete surface creation certain of pull should dint.when pull should dint exceed the anti- of concrete pull strength extreme limit, concrete surface meeting creation crack, this kind of crack much occurrence after the concrete under construction period.in the concrete of under construction be difference in temperature variety more big, perhaps is a concrete to be subjected to assault of cold wave etc., will cause concrete surface the temperature sharply descend, but creation constringency, surface constringency of the concrete be subjected to inner part concrete of control, creation very big of pull should dint but creation crack, this kind of crack usually just in more shallow scope of the concrete surface creation.conclusionthe crack is widespread in the concrete structure existence of a kind of phenomenon, it of emergence not only will lower the anti- shen of building ability, influence building of usage function, and will cause the rust eclipse of reinforcing bar, the carbonization of concrete, lower the durable of material, influence building of loading ability, so want to carry on to the concrete crack earnest research, differentiation treat, adoption reasonable of the method carry on processing, and at under construction adopt various valid of prevention measure to prevention crack of emergence and development, assurance building and gou piece safety, stability work.fromcanadian journal of civil engineering建筑施工混凝土裂缝混凝土的裂缝问题是一个普遍存在而又难于解决的工程实际问题，本文对混凝土工程中常见的一些裂缝问题进行了探讨分析。关键词：混凝土 裂缝 前言混凝土是一种由砂石骨料、水泥、水及其他外加材料混合而形成的非均质脆性材料。由于混凝土施工和本身变形、约束等一系列问题，硬化成型的混凝土中存在着众多的微孔隙、气穴和微裂缝，正是由于这些初始缺陷的存在才使混凝土呈现出一些非均质的特性。微裂缝通常是一种无害裂缝，对混凝土的承重、防渗及其他一些使用功能不产生危害。但是在混凝土受到荷载、温差等作用之后，微裂缝就会不断的扩展和连通，最终形成我们肉眼可见的宏观裂缝，也就是混凝土工程中常说的裂缝。混凝土裂缝产生的原因很多，有变形引起的裂缝：如温度变化、收缩、膨胀、不均匀沉陷等原因引起的裂缝；有外载作用引起的裂缝；有养护环境不当和化学作用引起的裂缝等等。在实际工程中要区别对待，根据实际情况解决问题。混凝土工程中常见裂缝:1.干缩裂缝干缩裂缝多出现在混凝土养护结束后的一段时间或是混凝土浇筑完毕后的一周左右。水泥浆中水分的蒸发会产生干缩，且这种收缩是不可逆的。干缩裂缝的产生主要是由于混凝土内外水分蒸发程度不同而导致变形不同的结果：混凝土受外部条件的影响，表面水分损失过快，变形较大，内部湿度变化较小变形较小，较大的表面干缩变形受到混凝土内部约束，产生较大拉应力而产生裂缝。相对湿度越低，水泥浆体干缩越大，干缩裂缝越易产生。干缩裂缝多为表面性的平行线状或网状浅细裂缝，宽度多在0.05-0.2mm之间，大体积混凝土中平面部位多见，较薄的梁板中多沿其短向分布。干缩裂缝通常会影响混凝土的抗渗性，引起钢筋的锈蚀影响混凝土的耐久性，在水压力的作用下会产生水力劈裂影响混凝土的承载力等等。混凝土干缩主要和混凝土的水灰比、水泥的成分、水泥的用量、集料的性质和用量、外加剂的用量等有关。2.塑性收缩裂缝塑性收缩是指混凝土在凝结之前，表面因失水较快而产生的收缩。塑性收缩裂缝一般在干热或大风天气出现，裂缝多呈中间宽、两端细且长短不一，互不连贯状态。较