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turn hot.five is an improvementconcrete ofmix blendto processa craft,lower sprinkleof concrete to build temperature.six is the inaddition that the chanadd ahave offixedamount to reduce waterand increasesu,slow ningetc.function in the concrete,improvement the concrete mixto matcha thingof mobility,protect water,lower watertoturn hot,postpone hotfeng ofemergence time.seven is the heatseason sprinkle tobuild canthe adoptiontake toestablish tohide sunplank etc.assistance measurecontrolconcrete ofwen sheng,lower to sprinkle temperatureof buildtheconcrete.eight is the temperatureof bigphysical volumeconcrete should the dintrelateto structuresize,concrete structuresize more big,temperature should dint more big,sowant reasonablearrangement constructionwork preface,layering,cent thepiecesprinkle tobuild,for theconvenience of in spread hot,let upcontrol.nine isat greatinner part constitutionof the physical volumeconcrete cool off piping,cold waterperhapscold aircool off,let upconcrete of inside outsidedifference in temperature.tenis thesupervision whichstrengthen concretetemperature,adopt tocooloffin time,protection measure.il is to reservetemperature constringencyto sew.12is tolet uptocontrol,sprinkle properbefore buildingconcrete in the jirock andold concrete top builda5mm or so sandmat alayer orusage asphalt etc.material tu2shua.13is tostrengthenconcreteto protect,the concreteafter sprinklebuild usemoist grasslian intime,hemp slicesetc.overlay,and attentionsprinkle water to protect,appropriateextension protecttime,assurance the concrete surfacebe slow-moving cooloff.at thecoldseason,concrete surfaceshould constitutionheat preservationmeasure,in ordertoprevent cold wave assault.14istheallocation be a littleamount in the concrete ofreinforcing barperhaps addfiber materialconcrete of temperature crackcontrol atcertain of scopeinside.
5.crack andprevention that the chemical reaction causealkalibones anticipatingthe crack that reactioncrack andreinforcing barrusteclipse causeisthemost familiarin thereinforced concrete structure ofbecause ofchemicalreaction butcause of crack.the concreteblend afuture reunioncreation somealkalescence ion,these ionwithsome activitythe bone anticipate creationchemicalreactionand absorbsurroundingsenvironment inof waterbut thephysical volumeenlarge,make concretecrisploose,inflation opencrack.in this kind of crack generalemergence concretestructureusage period,once appearvery difficultremediable,so shouldat underconstruction adopt validthe measurecarry onprevention.main of preventionmeasure:while beingto choose to anticipatewith thealkali activitysmall freestonebone.two isthe inaddition which choose to use lowlye mirewith lowalkali orhave noalkali.three isthe chanwhichchoose to useaccommodation withanticipate torepressan alkalibone toanticipate reaction.because the concrete sprinkletobuild,flap daobad perhaps isa reinforcing barprotectionlayer thinner,the harmfulmaterial getinto concreteto makereinforcing barcreationrust eclipse,the reinforcing bar physical volume of the rust eclipse inflation,cause concretebulge crack,the crack of this kind typemuch isa cracklengthways,follow theposition of reinforcing barappear.usually ofprevent measurefrom have:oneis assurancereinforcing barprotection thethickness of the layer.two isa concreteclassto gotogether withto wantgood.three isa concreteto sprinkleto noteand flapdaoairtight solid.four isareinforcingbar surfacelayer tu2shua antisepsiscoating.crack processingthe emergence of the cracknot onlywould influencestructure ofwhole withjustdegree,return will cause the rust eclipse of reinforcingbar,acceleration concrete ofcarbonization,lower durableand anti-of concretetired,anti-shen ability.thereforeaccording to the propertyof crack and concretecircumstance wewant differentiation totreat,in timeprocessing,with assurance building ofsafety usage.the repairmeasure of the concrete crack ismain to have the following somemethod:surface repair method,infuse syrup,the qiansew method,the structurereinforce a method,concrete displacementmethod,electricity chemistry protectionmethod andimitate to living from heal method.surface repairthe methodbe a kind ofsimple,familiar ofrepairmethod,it mainbe applicable tostability andto structureloading theability donthave thesurface crackof influence anddeep entercrack ofprocessing.the processing measure thatis usuallyisa surface in crackdaubery cement syrup,the wreathoxygen gum mire orat concretesurfacetu2shua paint,asphaltetc.antisepsis material,at protectionofin the meantimeforkeeping concrete from continueunder the influence ofvarious functionto opencrack,usually canadoption thesurfaceincrack glue to stickglass fibercloth etc.measure.1,infuse syrup,the qiansew methodinfusea syrupmethod main the concretecrack beenapplicable tohave influenceorhave alreadydefend shenrequest tothe structurewhole ofrepair,it ismake use ofpressure equipmentsgum knotthe materialpress intothe crack of concrete,gum knotthematerial hardenbehind andconcrete formationone bewhole,thus reinforceofpurpose.the in common usegum knotmaterial hasthe cementthe syrup,epoxy,a jicxi sourester andgather ammoniaester toequalize tolearn material.the qiansew a method isthat the crack bea kind of mostincommon use methodin,it usuallyis followthe crackdig slot,the qianfill suin theslot orrigid water materialwith attainclosing crackof purpose.the incommon usesu materialhas pvcgummire,plastics ointment,the dji rubberetc.;ln commonuse rigidwatermaterialisthepolymercement sand syrup.2,the structurereinforceamethodwhen the crack influencearrive concrete structure of function,will considerationadoptto reinforceamethodto carryon processingtothe concretestructure.thestructure reinforcemedium incommonusemain havethefollowinga fewmethod:thepiece ofenlargement concretestructure inevery aspectaccumulate,outside thecapedepartment of the goupiece packtype steel,adoption prepareshouldthedint methodreinforce,gluetostick steelplate toreinforce,increase toestablish fulcrumto reinforceandjet the concrete compensationreinforce.3,concrete displacementmethodconcrete displacementmethod isprocessing severitydamage concrete of akind ofvalidmethod,this methodbe firstwill damageof the concrete pickand getrid of,then againdisplacementgo intonew of concrete orother material.the incommon usedisplacementmaterial have:common concrete or thecement sandsyrup,polymer orchangesex polymerconcreteorsandsyrup.4,the electricitychemistryprotection methodthe electricitychemistry antisepsisistomake useof inflictionelectric fieldin liethequality ofelectricity chemicaleffect,change concreteor reinforcedconcrete theenvironmentappearance of the place,the bluntnessturn reinforcingbar toattain thepurposeof antisepsis.cathode protectionmethod,chlorine saltswithdrawing amethod,alkalescence torecover amethod isa chemistryprotectionmethodin threekinds ofincommon usebut validmethod.the advantageof thiskind ofmethod isa protectionmethodunder theinfluence ofenvironment factorsmaller,apply reinforcingbar,concrete oflong-term antisepsis,since canused forcrack structurealready canalsoused fornew setup structure.5,imitate toliving fromlegal moreimitatetolivingfromhealthe methodbeakind ofnew cracktreatment,its mimicrylivingcreature organizationsecrete acertain materialtowards sufferingwound partauto,but make the woundpart healoffunction,join someand specialcompositionsuchas containto glueknot of the liquidxin fiberor capsulein the concrete of the traditionthecomposition,at concrete inner partformation theintelligence typeimitate tolivingfrom healnerve networksystem,be the concrete appear crack secretea partsof liquidxinfiber canmake the crack re-heal.conclusionthe crack is widespreadin theconcretestructureexistence of akindofphenomenon,it ofemergence notonly willlower the anti-shen ofbuilding ability,influence buildingof usagefunction,and willcause therust eclipseof reinforcingbar,the carbonizationof concrete,lower thedurable ofmaterial,influence buildingofloading ability,so want to carryontotheconcretecrack earnestresearch,differentiation treat,adoption reasonableof themethod carryon processing,and atunder constructionadoptvarious valid of preventionmeasure toprevention crackofemergence and development,assurancebuildingand goupiece safety,stability work.《》from canadianjournal ofcivil engineering中文原文:建筑施工混凝土裂缝日勺防止与处理混凝土的i裂缝问题是一种普遍存在而又难于处理的工程实际问题，本文对混凝土工程中常见的某些裂缝问题进行了探讨分析，并针对详细状况提出了某些防止、处理措施关键词混凝土裂缝防止处理序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自身变形、约束等一系列问题，硬化成型的混凝土中存在着众多的i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展现出某些非均质的特性微裂缝一般是一种无害裂缝，对混凝土的承重、防渗及其他某些使用功能不产生危害不过在混凝土受到荷载、温差等作用之后，微裂缝就会不停的扩展和连通，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建筑和构件一般都是带缝工作的，由于裂缝的存在和发展一般会使内部的钢筋等材料产生腐蚀，减少钢筋混凝土材料的承载能力、耐久性及抗渗能力,影响建筑物的i外观、使用寿命，严重者将会威胁到人们的i生命和财产安全诸多工程的失事都是由于裂缝的不稳定发展所致近代科学研究和大量的混凝土工程实践证明，在混凝土工程中裂缝问题是不可防止欧i,在一定日勺范围内也是可以接受的，只是要采用有效的措施将其危害程度控制在一定的i范围之内钢筋混凝土规范也明确规定有些构造在所处日勺不同样条件下，容许存在一定宽度的裂缝但在施工中应尽量采用有效措施控制裂缝产生，使构造尽量不出现裂缝或尽量减少裂缝的数量和宽度，尤其要尽量防止有害裂缝欧i出现，从而保证工程质量混凝土裂缝产生的原因诸多，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；有养护环境不妥和化学作用引起的裂缝等等在实际工程中要区别看待，根据实际状况处理问题混凝土工程中常见裂缝及防止
1.干缩裂缝及防止干缩裂缝多出目前混凝土养护结束后的i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重要是由于混凝土内外水分蒸发程度不同样而导致变形不同样的成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-
0.2nlm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一般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重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、外加剂口勺用量等有关重要防止措施一是选用收缩量较小的i水泥，一般采用中低热水泥和粉煤灰水泥，减少水泥的i用量二是混凝土的i干缩受水灰比的i影响较大，水灰比越大，干缩越大，因此在混凝土配合比设计中应尽量控制好水灰比的选用，同步掺加合适的减水剂三是严格控制混凝土搅拌和施工中的配合比，混凝土的用水量绝对不能不不大于配合比设计所给定的用水量四是加强混凝土的初期养护，并合适延长混凝土的养护时间冬季施工时要合适延长混凝土保温覆盖时间，并涂刷养护剂养护五是在混凝土构造中设置合适的收缩缝
2.塑性收缩裂缝及防止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，互不连贯状态较短日勺裂缝一般长20-30cm,较长的i裂缝可达2-3m,宽其产生欧i重要原由于混凝土在终凝前几乎没有强度或强度很小，或者混凝土刚刚终凝而强度很小时，受高温或较大风力的i影响，混凝土表面失水过快，导致毛细管中产生较大的负压而使混凝土体积急剧收缩，而此时混凝土的强度又无法抵御其自身收缩，因此产生龟裂影响混凝土塑性收缩开裂的重要原因有水灰比、混凝土的i凝结时间、环境温度、风速、相对湿度等等重要防止措施一是选用干缩值较小初期强度较高的硅酸盐或一般硅酸盐水泥二是严格控制水灰比，掺加高效减水剂来增长混凝土的坍落度和和易性，减少水泥及水的i用量三是浇筑混凝土之前，将基层和模板浇水均匀湿透四是及时覆盖塑料薄膜或者潮湿的草垫、麻片等，保持混凝土终凝前表面湿润，或者在混凝土表面喷洒养护剂等进行养护五是在高温和大风天气要设置遮阳和挡风设施，及时养护
3.沉陷裂缝及防止沉陷裂缝日勺产生是由于构造地基土质不匀、松软或回填土不实或浸水而导致不均匀沉降所致；或者由于模板刚度局限性，模板支撑间距过大或支撑底部松动等导致，尤其是在冬季，模板支撑在冻土上，冻土化冻后产生不均匀沉降，致使混凝土构造产生裂缝此类裂缝多为深进或贯穿性裂缝,其走向与沉陷状况有关,一般沿与地面垂直或呈30°-45°角方向发展，较大的沉陷裂缝，往往有一定的i错位，裂缝宽度往往与沉降量成正比关系裂缝宽度受温度变化的影响较小地基变形稳定之后，沉陷裂缝也基本趋于稳定重要防止措施一是对松软土、回填土地基在上部构造施工前应进行必要的扎实和加固二是保证模板有足够的强度和刚度，且支撑牢固，并使地基受力均匀三是防止混凝土浇灌过程中地基被水浸泡四是模板拆除的时间不能太早，且要注意拆模的先后次序五是在冻土上搭设模板时要注意采用一定的防止措施
4.温度裂缝及防止温度裂缝多发生在大体积混凝土表面或温差变化较大地区的混凝土构造中混凝土浇筑后，在硬化过程中，水泥水化产生大量的水化热，（当水泥用量在350-550kg/m3,每立方米混凝土将释放出17500-27500kj的热量，从而使混凝土内部温度升达70℃左右甚至更高）由于混凝土的体积较大，大量的水化热聚积在混凝土内部而不易散发，导致内部温度急剧上升，而混凝土表面散热较快，这样就形成内外的较大温差，较大的温差导致内部与外部热胀冷缩的程度不同样，使混凝土表面产生一定的拉应力当拉应力超过混凝土的抗拉强度极限时，混凝英文原文building constructionconcretecrackofprevention andprocessingabstractthe crackproblem of concrete isa widespreadexistence butagain difficultin solveofengineering actualproblem,this textcarried ona studyanalysis toa little bit familiarcrackproblem in theconcrete engineering,and aimat concretethe circumstanceputforward someprevention,processingmeasure.keyword:concrete crackpreventionprocessing forewordconcretesising1kind isanticipate bythe freestonebone,cement,water andothermixture butformation of theinaddition materialof qualitybrittleness not and allmaterial.because theconcrete constructiontransform withoneself,control etc.a seriesproblem,harden modelofin theconcreteexistence numeroustiny hole,spirit caveandtiny crack,is exactlybecause thesebeginning startblemish of existence justmake theconcretepresent onesome notand allthe characteristicof quality.the tiny crackisakind ofharmless crack and acceptconcrete heavy,defend shenand alittlebitother usefunctionnotacreation toendanger.but after theconcrete be subjected to lotuscarry,difference intemperature etc.function,tinycrackwould continuouslyof expandwith土表面就会产生裂connect,end formationwe cansee withoutthe aidof instrumentsof缝，这种裂缝多发生在混凝土施工中后期在混凝土的i施工中当温差变化较大，或者是混凝土受到寒潮的袭击等，会导致混凝土表面温度急剧下降，而产生收缩，表面收缩的混凝土受内部混凝土的约束，将产生很大的拉应力而产生裂缝，这种裂缝一般只在混凝土表面较浅的范围内产生温度裂缝的走向一般无一定规律，大面积构造裂缝常纵横交错；梁板类长度尺寸较大的构造，裂缝多平行于短边；深入和贯穿性的i温度裂缝一般与短边方向平行或靠近平行，裂缝沿着长边分段出现，中间较密裂缝宽度大小不一，受温度变化影响较为明显，冬季较宽，夏季较窄高温膨胀引起的混凝土温度裂缝是一般中间粗两端细，而冷缩裂缝的粗细变化不太明显此种裂缝的出现会引起钢筋的i锈蚀，混凝土的碳化，减少混凝土欧i抗冻融、抗疲劳及抗渗能力等重要防止措施一是尽量选用低热或中热水泥，如矿渣水泥、粉煤灰水泥等二是减少水泥用量，将水泥用量尽量控制在450kg/m3如下三是减少水灰比，一般混凝土的水灰比控制在
0.6如下四是改善骨料级配，掺加粉煤灰或高效减水剂等来减少水泥用量，减少水化热五是改善混凝土的搅拌加工工艺，减少混凝土的浇筑温度六是在混凝土中掺加一定量的具有减水、增塑、缓凝等作用的外加剂，改善混凝土拌合物的流动性、保水性，减少水化热，推迟热峰的出现时间七是高温季节浇筑时可以采用搭设遮阳板等辅助措施控制混凝土的i温升，减少浇筑混凝土的温度八是大体积混凝土的温度应力与构造尺寸有关，混凝土构造尺寸越大，温度应力越大，因此要合理安排施工工序，分层、分块浇筑，以利于散热，减小约束九是在大体积混凝土内部设置冷却管道，通冷水或者冷气冷却，减小混凝土的内外温差十是加强混凝土温度的监控，及时采用冷却、保护措施十一是预留温度收缩缝十二是减小约束，浇筑混凝土前宜在基岩和老混凝土上铺设5mm左右的砂垫层或使用沥青等材料涂刷十三是加强混凝土养护，混凝土浇筑后，及时用湿润的草帘、麻片等覆盖，并注意洒水养护，合适延长养护时间,保证混凝土表面缓慢冷却在寒冷季节，混凝土表面应设置保温措施，以防止寒潮袭击十四是混凝土中配置少许的钢筋或者掺入纤维材料将混凝土的温度裂缝控制在一定的i范围之内
5.化学反应引起的裂缝及防止碱骨料反应裂缝和钢筋锈蚀引起於i裂缝是钢筋混凝土构造中最常见的由于化学反应而引起的裂缝混凝土拌和后会产生某些碱性离子，这些离子与某些活性骨料产生化学反应并吸取周围环境中的水而体积增大，导致混凝土酥松、膨胀开裂这种裂缝一般出现中混凝土构造有效期间，一旦出现很难补救，因此应在施工中采用有效措施进行防止重要的防止措施一是选用碱活性小的砂石骨料二是选用低碱水泥和低碱或无碱的i外加剂三是选用合适的掺和料克制碱骨料反应由于混凝土浇筑、振捣不良或者是钢筋保护层较薄，有害物质进入混凝土使钢筋产生锈蚀，锈蚀的钢筋体积膨胀，导致混凝土胀裂，此种类型的i裂缝多为纵向裂缝，沿钢筋的i位置出现一般的防止措施有一是保证钢筋保护层的厚度二是混凝土级配要良好三是混凝土浇注要振捣密实四是钢筋表层涂刷防腐涂料裂缝处理裂缝欧i出现不仅会影响构造的整体性和刚度，还会引起钢筋欧i锈蚀、加速混凝土的j碳化、减少混凝土的耐久性和抗疲劳、抗渗能力因此根据裂缝的性质和详细状况我们要区别看待、及时处理，以保证建筑物的安全使用混凝土裂缝的修补措施重要有如下某些措施表面修补法，灌浆、嵌缝封堵法，构造加固法，混凝土置换法，电化学防护法以及仿生自愈合法表面修补法是一种简朴、常见的修补措施，它重要合用于稳定和对构造承载能力没有影响的表面裂缝以及深进裂缝的处理一般的i处理措施是在裂缝的表面涂抹水泥浆、环氧胶泥或在混凝土表面涂刷油漆、沥青等防腐材料，在防护的同步为了防止混凝土受多种作用的影响继续开裂，一般可以采用在裂缝的表面粘贴玻璃纤维布等措施
1、灌浆、嵌缝封堵法灌浆法重要合用于对构造整体性有影响或有防渗规定的混凝土裂缝的i修补，它是运用压力设备将胶结材料压入混凝土的裂缝中，胶结材料硬化后与混凝土形成一种整体，从而起到封堵加固的目的常用的胶结材料有水泥浆、环氧树脂、甲基丙烯酸酯、聚氨酯等化学材料嵌缝法是裂缝封堵中最常用的一种措施，它一般是沿裂缝凿槽，在槽中嵌填塑性或刚性止水材料，以抵达封闭裂缝的目的常用的塑性材料有聚氯乙烯胶泥、塑料油膏、丁基橡胶等等；常用的i刚性止水材料为聚合物水泥砂浆
2、构造加固法当裂缝影响到混凝土构造的性能时，就要考虑采用加固法对混凝土构造进行处理构造加固中常用的重要有如下几种措施加大混凝土构造的截面面积，在构件的i角部外包型钢、采用预应力法加固、粘贴钢板加固、增设支点加固以及喷射混凝土补强加固
3、混凝土置换法混凝土置换法是处理严重损坏混凝土的一种有效措施，此措施是先将损坏的混凝土剔除，然后再置换入新的混凝土或其他材料常用的置换材料有一般混凝土或水泥砂浆、聚合物或改性聚合物混凝土或砂浆
4、电化学防护法电化学防腐是运用施加电场在介质中的电化学作用，变化混凝土或钢筋混凝土所处的环境状态，钝化钢筋，以抵达防腐的目的i阴极防护法、氯盐提取法、碱性复原法是化学防护法中常用而有效的三种措施这种措施的长处是防护措施受环境原因欧i影响较小，合用钢筋、混凝土的长期防腐，既可用于已裂构造也可用于新建构造
5、仿生自愈合法仿生自愈合法是一种新的裂缝处理措施，它模仿生物组织对受创伤部位自动分泌某种物质，而使创伤部位得到愈合的j机能，在混凝土的j老式成分中加入某些特殊成分（如含粘结剂的液芯纤维或胶囊），在混凝土内部形成智能型仿生自愈合神经网络系统，当混凝土出现裂缝时分泌出部分液芯纤维可使裂缝重新愈合结论裂缝是混凝土构造中普遍存在的一种现象，它的出现不仅会减少建筑物的抗渗能力，影响建筑物的使用功能，并且会引起钢筋的锈蚀，混凝土的i碳化，减少材料的耐久性，影响建筑物的承载能力，因此要对混凝土裂缝进行认真研究、区别看待，采用合理的措施进行处理，并在施工中采用多种有效的防止措施来防止裂缝日勺出现和发展，保证建筑物和构件安全、稳定地工作出自《加拿大土木工程学报》macro viewthe crackbe alsothe crack that theconcrete oftensay in the engineering.concrete buildingand goupiece usuallyall takesewer tomake of,because ofcrackofexistenceanddevelopmentusually makeinner partof reinforcingbar etc.material creationdecay,lower reinforcedconcrete materialof loadingability,durableand anti-shen ability,influence buildingof externalappearance,service life,severitywill threatarrive peopleslife and property safety.a lot of allof crashof engineeringsisbecause of the unsteadydevelopment ofthe crackwith the result that.modern agescienceresearch witha great deal of oftheconcrete engineeringpractice certificate,inthe concreteengineering crackproblem is ineluctable,also acceptablein certainlyof thescopejust needto adoptvalidofmeasure willit endangerdegree controlat certain ofscope inside.the reinforcedconcrete normis alsoexplicit provision:some structureatplace ofdissimilarity under the conditionallow existencecertain thecrackofwidth.butat underconstruction shouldas far as possibleadopt avalid measurecontrol crackcreation,makethestructure dontappearcrackpossibly oras faras possibledecreasecrack ofamount andwidth,particularly wantto as faras possible avoidharmful crackofemergence,insure engineeringquality thus.concrete crackcreation ofthe reasonbealotofand havealready transformedtocause of crack:such astemperature variety,constringency,inflation,the asymmetrysinkto sinketc.reason causeof crack;have outsidecarry thecrackthatthe functioncause;protected environmentnot appropriatethecracketc.caused withchemicaleffect.want differentiationto treatin the actual engineering,work°out aproblemaccording totheactualcircumstance.in theconcreteengineeringthe familiarcrackand the preventionl.stem suo crackandpreventionstem the suo crack much appearafter theconcrete protectbe overofaperiod oftimeor concretesprinkletobuild tocomplete behindof arounda week.in thecementsyrup humidityof evaporatewould creationstem suo,and thiskindofconstringency iscantnegative.stem suo crackofthe creationbe mainis becauseof concreteinsideoutside humidityevaporate degreedissimilarity butcause totransform dissimilarityofresult:the concreteis subjected to exteriorcondition ofinfluence,surface humiditylosslead quick,transform bigger,inner partdegree ofhumidity variety smaller transformsmaller,bigger surfacestem thesuo transformto be subjected toconcrete inner partcontrol,creation morebig pull shoulddint but creation crack.the relative humidity ismorelow,cementsyrupbody stemsuo morebig,stem thesuo crackbe moreeasycreation.stem thesuocrackis muchsurface parallellines formor thenet shallowthincrack,width manybetween
0.05-
0.2mm,the flatsurface partmuch seein thebigphysical volumeconcrete andfollow itmore inthinner beamplank shorttodistribute.stem suocrack usuallythe anti-shen ofinfluence concrete,cause thedurableof therusteclipseinfluence concrete ofreinforcingbar,underthefunction ofthe waterpressuredint wouldcreation thewaterpower splitcrack influenceconcreteofloading dintetc..concrete stemthesuo bemain withwater ashoftheconcrete ratio,the dosage ofthecomposition,cement ofcement,gather toanticipate ofthe dosageoftheproperty anddosage,inaddition etc.relevant.main preventionmeasure:while beingto chooseto usethe constringencyquantitysmaller cement,general lowhot watermire andpowder ash from stovecementin theadoption,lower thedosageofcement.two isa concreteof stemthe suobe subjected towater ash ratio ofinfluence morebig,water ashratio morebig,stemsuo morebig,so intheconcretematch theratio thedesign shouldas faras possiblecontrolgood water ashratioof choosetouse,the chanadd inthe meantimeaccommodationof reducewater.three isstrict controlconcrete mixblend withunderconstruction ofmatch ratio,useof concrete waterquantity absolutecant bigin matchratiodesign givesettle ofuse waterquantity.four isthe earlierperiod whichstrengthenconcrete to protect,and appropriate extension protectofconcretetime.winterconstruction wantto beappropriateextensionconcrete heatpreservation to overlaytime,and tu2shua protecttoprotect.five isa constitutionthe accommodationis intheconcrete structureoftheconstringency sew.
2.the suconstringency crackand preventionsuconstringency istheconcreteis beforecondense,surface becauseof losewaterquicker but creation ofconstringency.the suconstringency crackis generalat dryheator strongwind theweather appear,cracks muchpresenting inthe centerbreadth,both endsbe inthe centerthinandthelength be different,with eachother notcoherentappearance.shorter crack general long20-30cm,the longercrack canreach toa2-3m,breadth1-5mm.lt creationof mainreason is:the concreteis eventuallyalmosthaving nostrength orstrength beforethe ningvery small,perhaps concretejusteventually ningbut strengthvery hour,be subjectedto heator comparestrong winddintofinfluence,theconcrete surface losewater tolead quick,result ininthecapillarycreation biggernegative pressbut makea concretephysical volumesharplyconstringency,but atthis timethe strengthofconcreteagain cantresist itsconstringency,therefore creation cracked.the influenceconcrete suconstringencyopen themain factorofcracktohavewater ashratio,concreteofcondense time,environment temperature,wind velocity,relativehumidity...etc..main preventionmeasure:one ischoosetouse stemthesuovalue smallerhigherhuo soursalt ofthe earlierperiod strengthor commonthe huosour brinemire.two isstrictthe controlwater ashratio,the chanadd toefficiently reducewater toincrementthe collapseofconcretefall adegree andwith easy,decrease cementand waterofdosage.three istosprinklebefore buildingconcrete,water basiclevel andtemplateeven tosoak through.four isin timetooverlaythe perhapsdamp grassmat oftheplastics thinfilm,hemp sliceetc.,keep concreteeventually beforethe ningsurface ismoist,perhaps spraytoprotectetc.to carryon protect intheconcrete surface.five isinthe heatand strongwind theweather towanttoestablish tohide sunand blockbreezefacilities,protectintime.
3.sink to sink crackand preventionthecreation whichsink to sink crackis becauseofthestructure foundationsoilquality notand evenly,loose softor return to fillsoil dishonestor soakin waterbutresult inthe asymmetrysink to decline withtheresultthat;perhaps becauseof templatejustdegree shortage,the templatepropped upto oncebe apartfrom bigor prop upbottom loosemove etc.to cause,especially atwinter,the templatepropupat jellysoilup,jelly thesoil turnjelly empresscreation asymmetryto sinkto declineand causeconcretestructure creationcrack.this kind crack manyis deepenter orpierce throughsexcrack,it alignmenthave somethingto dowith sinkingtosinka circumstance,general followwith groundperpendicular orpresent30°s-45°cape directiondevelopment,bigger sinktosinkcrack,usually havecertainofwrong,crack widthusuallywith sinktodeclinequantity directproportion relation.crack widthunder theinfluenceof temperaturevarietysmaller.the foundationafter transformstability sinktosink crackalso basictend instability.main preventionmeasure:one isrightness loosesoft soil,returntofill soilfoundationa constructionattheupper partstructure frontshould carryon necessityofhang solidwith reinforce.two isthe strengththat assurancetemplate isenough andjustdegree,andpropup firm,and makethe foundationbesubjectedto dinteven.threeis keepconcretefromsprinkle infusingthe foundationintheprocess issoak bywater.four istime thattemplate toredown tocant betoo early,and wantto noticetodismantle amold orderof sequence.five isat jellysoil toptake toestablish templatetonotice toadopt certainofpreventionmeasure.
4.temperature crackand preventiontemperaturecrackmuchthe occurrenceisinbig surfaceor difference intemperature varietyofthephysicalvolumeconcrete comparethe eartharea oftheconcrete structure.concrete aftersprinkling tobuild,inthehardening theprocess,cement water turn acreation a greatdealofofwater turnhot,.be thecement dosageisinthe350-550kg/m3,each signsquare therice concretewill releasea caloriesof17500-27500kj andmake concreteinternal thusthe temperaturerise toreach to70℃orsoeven higherbecausethephysicalvolume ofconcrete bemorebig,agreatdeal ofofwaterturnhot accumulateattheconcreteinnerpart butnot easysend forth,causeinner partthe temperaturehoick,but theconcretesurfacespreadhotmore quick,soformation insideoutside ofbigger differenceintemperature,the biggerdifferenceintemperatureresult ininnerpartand exteriorhot thedegree ofthe bulgecold suodissimilarity,make concretesurface creationcertainofpull shoulddint.when pullshoulddint exceedthe anti-ofconcretepull strengthextreme limit,concrete surfacemeetingcreationcrack,thiskindofcrackmuch occurrenceaftertheconcrete underconstructionperiod.in theconcreteofunderconstructionbe differencein temperaturevarietymorebig,perhapsisa concreteto besubjectedtoassault ofcoldwaveetc.,willcause concretesurface thetemperature sharplydescend,butcreationconstringency,surface constringencyoftheconcretebesubjectedtoinnerpartconcreteofcontrol,creation verybig ofpullshoulddintbutcreationcrack,thiskindofcrackusually justinmore shallowscope oftheconcretesurface creation.the alignmentofthetemperature crackusually nonesettle regulation,big areastructurethecrackoften maneuverinterleave;the sizebigger structureofthebeamplank length,thecrackrun parallelwith shortside more;thorough withpierce throughsexoftemperaturecrackgeneraland shortside directionparallelism orcloseparallelism,crack alonglong sidecent thesegment appear,inthecenter moreairtight.crack widththe sizebedifferent,besubjectedto temperaturevariety influencemoreobvious,winter comparebreadth,summer morenarrow.the concretetemperaturecrackthatthe heatinflation causeis usuallyinthecenter thethick bothendsbe thin,but coldsuocrackof thickthin varietynot tooobvious.theemergenceofthe thiskindcrackwillcausetherusteclipseofreinforcingbar,the carbonizationofconcrete,theanti-jelly whichlower concretemelt,anti-tired andanti-shen abilityetc..main preventionmeasure:one isas faras possiblechoosetouse lowhot ormediumhot watermire,like mineralresidue cement,powder ashfrom stovecement...etc..two isa decreasecement dosage,cement dosageasfaraspossiblethecontrol isinthe450kg/m3following.three isto lowerwater ashratio,waterashof thegeneralconcrete ratiocontrol below
0.
6.four isimprovement theboneanticipateclassto gotogether with,the chanadd powderashfromstove orefficiently reducewater etc.to cometoreducecement dosageand lowerwaterto。
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