混凝土裂缝论文中英文资料对照外文翻译文献综述.docx

混凝土裂缝论文中英文资料对照外文翻译文献综述.docx

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混凝土裂缝论文中英文资料对照外文翻译文献综述

混凝土裂缝论文

中英文资料对照外文翻译文献综述

Causesandcontrolmeasuresofconcretecracksstudytheproblem

Keywords:

Causespreventionofconcretecracks

Abstract:

Atpresent,paidcloseattentiontotheproblemofconcretecracks,thiscrackintheconcreteonthebasisofclassification,analysisofthecausesofdifferentcracks,andproposedmeasurestocrackpreventionandtreatment.

1.Introduction

Isthemaximumamountofconcreteasabuildingmaterial,widelyusedinindustrialandcivilconstruction,agricultureandforestrywithurbanconstruction,waterconservancyworksintheharbor.However,manyconcretestructuresoccursduringtheconstructionanduseofdifferentdegreesanddifferentformsoffracture.Thisnotonlyaffectstheappearaneeofthebuilding,butalsoendangerthenormaluseofbuildingsandstructuresdurability.Therefore,thecracksbecomepeopleconcerns.Inrecentyears,withtheready-mixedconcreteandvigorouslypromotetheuseandstructurebecomeincreasinglylarge,complex,makingtheproblemevenmoreprominent.However,cracksinconcretestructuresisafairlycommonphenomenon,largenumberofengineeringpracticeandmodernscieneeontheconcretestrengthofmicrostudiesshowthatthestructuresofthecrackisinevitable,whichisapropertyofthematerial.Therefore,thescientifictreatmentofcracksinthecrackproblemistoclassifyonthebasis,adopteffectivemeasurestoharmfullevelsofcrackcontroltotheextentpermitted.Thisconcretestructurewillcausecracksincommon,controlmeasuresandtherepairmethodtoanalyzesomelight.

2.Classificationofconcretecracks

2.1DividedbyCrackAccordingtothecausesofconcretecracks,structuralcracksandcanbedividedintotwomajorcategoriesofnon-structuralcracks.

⑴StructuralcracksCausedbyavarietyofexternalloadscracks,alsocalledloadcracks.Itineludestheexternalloadscausedbythedirectstresscracksandthestructureunderexternalloadscausedbysecondarystresscracks.

（2）Non-structuralcracksDeformationcausedbythechangefromavarietyofcracks.Itincludestemperature,shrinkageandswellingcausedbyfactorssuchasdifferentialsettlementcracks.Suchcracksinthestructurewhenthedeformationisrestrictedduetothestresscaused.Researchdatafromabroadandalargenumberofengineeringpractice,non-structuralcracksintheworksinthemajority,about80%,whichledtoshrinkagecracks.

2.2Dividedbythetimethecracks

（1）CracksduringconstructionIncludingplasticshrinkagecracks,settlementshrinkagecracking,dryingshrinkagecracks,shrinkagecracksitself,thetemperaturecracks,thecrackswereimproperconstructionoperations,theroleofearlyfrost,andsomeirregularcrackscausedbycracks.

（2）UseofcrackduringIncludingtheexpansionofsteelcorrosioncracksgenerated,saltandaciderosiontypeliquidmediumcausedbycracks,thecrackscausedbyfreezingandthawing,alkaliaggregatereaction,andcrackscausedbycyclicloadingcumulativedamagecausedbycracks.

2.3Classificationoffracturedbycracksintheshapeoftheshapecanbedividedby:

（1）Longitudinalcracksparalleltothebottomcomponent,thedistribution

alongtendons,mainlycausedbytheroleofsteelcorrosion

（2）Transversecracksperpendiculartothebottomcomponentmainlybythe

loading,temperatureeffectscaused

（3）Shearcracksduetodisplacementcausedbyverticalloadorvibration

（4）Diagonalcrackseightshapedorherringbonecracks,commorinthewallofconcretebeams,mainlyduetotheunevenfoundationsettlement,andthermal

effectscausedby

（5）X-shapedcrackscommonintheframeworkofbeams,columnsandwallson

theends,duetotheimpacteffect,ormomentloadscausedbyearthquake

（6）Allkindsofirregularcrackssuchasrepeatedfreezingandthawing,

orfirescausedbycracks

Inaddition,concretemixingandtransporttimeforlongcracksduetomesh,squareappearsfloorslaborplatesurfaceradialcracksappearinthecrosscracksandsoon.

2.4Thedevelopmentofthestatedividedbycracks

Accordingtofracturethemovementinwhichthestateanddevelopmenttrends,canbedividedintothefollowingcategories:

（"StablecrackThiscrackdoesnotaffectthepersistenceofapplications,including

twotypes.Oneisinmotiontheprocessofself-healingoffracturescouldbecommoninanumberofnewwaterprojects,thisisbecausethecrackofcementparticlesintheleakageofwaterfurthercompoundstheprocess,precipitateCa（OH）2crystalandpartoftheCa（OH）2hasdissolvedinthewaterwithCO2carbonationreactiontoformCaCO3crystallizationoccurs,boththeformationofcracksinthegelmaterialwillbegluedclosed,andthusstoptheleakage,crackstoheal.Theotherisinastablemovementofthecracks,suchastheperiodicloadgeneratedbythecyclicalexpansionandclosureofcracks.

（2）UnstablecrackThiswillresultininstabilityofcrackextension,affectingthesustainableuseofstructures,shouldbeconsideredpartofitsexpansion,totakecorrespondingmeasures.

3.Causesofcracksinconcreteandcontrolmeasures

3.1ShrinkagecracksShrinkagecracksarecausedbythehumidity,itaccountsfornon-structuralcracksinconcreteinthemainpart.Weknowthatconcreteisacementasthemaincementingmaterialtonaturalsand,stoneaggregatemixingwater,aftercastingmolding,hardensandtheformationofartificialstone」ntheconstruction,inordertoensureitsworkability,oftenaddingcementhydrationthanwaterneededfor4to5timesmorewater.Moreofthesewatertofreestateexists,andthegradualevaporationofthehardeningprocess,resultingintheformationoflargeporesinsidetheconcrete,voidsorholes,resultinginvolumeshrinkageofconcrete.Inaddition,thehardeningprocessofconcretehydrationandcarbonationofconcretevolumewillleadtoshrinkage.Accordingtotheexperimentaldeterminationoftheultimateshrinkageofconcreteisabout0104%~0106%.Showsthatshrinkageistheinherentphysicalpropertiesofconcrete,ingeneral,thelargerwater-cementratio,thehighertheconcretestrength,aggregateless,thehigherthetemperature,surfacewaterlossislarger,thelargerthevalueofitscontract,themoreeasilyshrinkagecracks.Accordingtotheformationofshrinkagecracksandformationmechanismofthetime,worksinthecommonshrinkagecracksaremainlyplasticshrinkagecracks,settlementshrinkagecrackinganddryingshrinkagecracksinthreecategories,inadditiontotheircontract（chemicalshrinkage）cracksandcarbonationshrinkagecracks.

3.1.1PlasticshrinkagecracksPlasticshrinkagecracksinconcreteplasticstage,beforethefinalset.Thecauseofthisisconcretepasteandquicklyevaporatingwaterflowtothesurface,withtheincreaseinwaterloss,capillarynegativepressuregeneratedbycontractionoftheconcretesurfaceofthedrasticvolumeshrinkage.Strengthofconcreteatatimehasnotyetformed,whichresultedincrackingoftheconcretesurface.Thismulti-cracksindryweather,hotandwindy,thefractureshallow,intermediatewidth,bothendsofthefine,ofdifferentlengths,anddisconnected.

3.1.2SettlementshrinkagecrackingSettlementshrinkagecracksinconcrete

pouringabouthalfanhouraftertheoccurreneeandhardeningstops.ThecauseofthisisoccurringaftertheslurryinthePouringunevensink,sinkingofcoarseaggregate,cementgroutfloat,whenthesettlementwasinhibited（suchassteelorembeddedpartsoftheblock）isduetoshearingandcrackingoftheconcrete.Inaddition,floatingintheplasmalayerformedonthesurfacewillbearesultofbleedingandcracking.Thismulti-cracksintheconcretesurface,andpassalongthelongdirectionofthereinforcement,orthestirrupsthedistributionwidthofbothendsofthenarrowmiddle,isacommonearlycracks,especiallyinthepumpconstructionismorecommon.

3.1.3DryingshrinkagecracksDryingshrinkagecracksintheconcretecuringonlyappearedaftercompletion.Itsformationwasmainlyduetotheconcretetoharden,thewaterevaporationcausedbyshrinkageoftheconcretesurface,whentheshrinkagedeformationofconcretebyinternalconstraint,haveagreatertensilestresstocracktheconcretesurfaceispulled.Shrinkagecracksonthesurfacegenerallyproducesveryshallowlocation,multi-componentalongtheshortdirectionofdistribution,wereparallel,linear,ormesh,canbeseverethroughoutthemembersection.

3.1.4Self-shrinkagecracksShrinkagecracksitselfhasnothingtodowiththeoutsidehumidity,butbecauseofthehydrationreactionofcementclinkerintheprocess,thereactionresultantoftheaveragedensityofsmallervolumeshrinkagecausedbysystem（calledchemicalshrinkage）due.Mainlyduetohydrationproductsoffreewaterintoapartofit39;sspecificvolumereducedby1/4（ie0125cm3Pg）.Therefore,thechemicalshrinkageofthesizeofthereductiondependsonthechemicalcombinationofcementhydrationproductsintheamountofwater.

3.1.5CarbonationshrinkagecrackingCarbonationcarbonationshrinkagecracks

arefreeionsgeneratedbywaterevaporation,causingshrinkageintheslurry.CarbonationisatmosphericCO2conditionsinthewaterreactswiththehydrationproductofCaCO3,alumina,silicaandwaterfreestate,thispartofthevolumeshrinkageofconcretecausedbywaterevaporation（knownascarbonationshrinkage）,anditsessenceisthecarbonateofthecementcorrosion.Generalalkalinityofcement