混凝土楼板开裂原因及处理方法Causes and treatment methods of con.docx

混凝土楼板开裂原因及处理方法Causes and treatment methods of con.docx

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混凝土楼板开裂原因及处理方法Causesandtreatmentmethodsofcon

混凝土楼板开裂原因及处理方法（Causesandtreatmentmethodsofconcretefloorcracking）

Causesofcrackingofconcretefloorslabandprocessingmethod

Residentialprojectscurrentlyfilledconcretefloorandwallcracksaremorecommon,accordingtotherelevantmaterialsandcombiningthesituationofmycompany,analysisofthecausesandCountermeasuresofcast-in-placeconcretefloorandmasonrywallcracksareasfollows,forreferenceinthework.

Thetypesofcracksintheconcretefloor,thecast-in-place

1.longitudinalcracks:

cracksalongthelongitudinaldirectionofthebuilding,thereareintheleather,downthroughtheindividual.

2.:

thetransversecracksinthespanrangeof1/3,thecracksalongthebuildingtransversedirection,thereareintheleather,downthroughtheindividual.

The3.cornercracksintheinclinedcracksappearfourcorneroftheroom,inthemajorityofepithelial.

4.irregularcrack:

crackdistributionanddirectionareirregular.

5.floor:

therootoftransversecracksfromcrackbearingin30cm,locatedintheepithelium.

6.embeddedalongthecrackdirectionofthewirepipe.

Causesofcracksinthefloor,two

1.design

1.1structuredesignsafetyreserveisrelativelysmall,insufficientreinforcementorsmallersection,thebeamformingpoorrigidity,theoveralldeflection,causedbythefourcornersoftheboardcrack.

1.2designofplatethicknessisnotenough,nordothedeflection,theoveralldeflection,causedbythefourcornersoftheboardcrack.

The1.3houseislongnotsetexpansionjoints,cracksintheweaklink.（AmericanConcreteInstitutedatasuggestthatconcreteshrinkageandtemperaturedeformationoftwokindsofdryshrinkagedeformationofeach30.48mabout19mm.shrinkagecausedbythechangeoftemperatureis37DEGC,thetemperaturechangeofeach30.48mcontractionorextensionof19mm.Somepeoplethinklongitudinalcontraction40mlongfloorduetohardeningandfreezingwas8-20mm.）

1.4basicdesignimpropertreatmentcausedbyunevensettlement,sothestructuretogenerateadditionalstress,resultinginfloorcracks.

The1.5floortwo-wayforcebyone-wayslabreinforcement,causingcracks.

2.reasonsforcommercialconcrete

2.1watercementratio,cementcontent.

2.2highperformanceretarderdosageistoolarge,notinthesolidificationfrontstonesink,producedheavycrack,oftenoccurinthebeamplatejunction.

2.3gravelgradationqualityisnotgood,notgood,largeamountofmud,containinglargeamountofpowder.

3,construction

3.1maintenanceisnotinplace,themandatoryrequirementsofconcretecuringtocoverandwater,nowmostdonotcover,wateringcannotguaranteeoftenmoist.

3.2theconstructionspeed,bearingonearly,especiallybrickresidentialfloor,thedaybeforepouringfloor,seconddaysonthebrick,takethecar,resultinginearlyconcretedamage.

3.3duringthecoldwinter.

3.4orearlyformremovalofformworksupportsystemstiffnessisnotenough.

3.5concretesurfacelaitancethickness,surfacestrengthisnotenough.

3.6duringtheconstructionofconcreteslabreinforcementcoverissteppedonbending,steppeddown,theprotectivelayeristoothick,thedecreaseofbearingcapacity.

Three,topreventtheconcretefloorcrackingmeasures

1.design

1.1intheuseofsmalldiametersteelcase,appropriatelyincreasingthereinforcementratio,theultimatetensilestrainofconcretecanbeimproved.

The1.2cornersofthenegativereinforcementtwo-wayconfiguration,

Unidirectionalplateisalsosurroundedbyboththeconfigurationofnegativereinforcement.

1.3inthesamereinforcementrate,reinforcedwithsmallerdiameter,reducingreinforcementspacing,canimprovethecrackresistanceofcast-in-placeslab.

2.construction

2.1cast-in-placefloortrytosetexpansionjoints,longitudinallengthofexpansionjointspacingofabout14mordesirableresidentialbuildingaunit,locatedintheslab,widthof10mm,themiddleofthesoftmaterials,andcontinuouslyreinforcedconcretebreak.

2.2steelbindingtoensureuniformspacing,ensurethenegativereinforcementpositionunchanged,pouringconcretesetMaRoad,notonthenegativereinforcement.

2.3usingtheplatevibrator,twopressingactivity,secondtimeswipingpressureinthefinalsetting.

2.4inthepreburiedwirepipewithsteelmesh,embeddedpipeasfaraspossiblealongthearrangementdirectionofreinforcementforce.

2.5byusingthemethodofcoveringandwateringmaintenance,coverageandwateringismandatoryrequirements,weareonlywatering,nocover,waterafterdryingcannotguaranteethetimelysupplement,themaintenanceperiodcannotguaranteecontinuousconcreteinwetstate,notuptotheeffectofmaintenanceshouldbe.

2.6concreteupto1.2MPanot,butearlydismantling,orbyearlyremovingsystem,keeptheverticalsupportafterstripping.

3,mixingstation

3.1toensuretheslumpofproductiondesign,tothescenefoundsegregationtotwomixing.

3.2toensurethequalityofcementandsand,ensurethescientificandreasonablemix.

3.3SRAwillsoonbeavailable,reducingagentinconcretemixingcanreduceshrinkagecracks.

Four,concretefloorcracks

4.1crackwidthlessthan0.3mmwith6202cementclosed.

4.2crackwidthisgreaterthan0.3mmbychemicalgrouting,thepracticeisasfollows:

（1）:

chiselchiselseamalongthecrack,crackcutaccordingtothewidthanddepthof15~20mmVslot.

（2）:

embeddedgroutingpipealongthecrackdirectionevery50cmdrillingaburiedgroutingnozzle,fixedbyglue.

（3）:

aclosedfracturestructureadhesiverepeatedlyscraped,andclosedaroundthecrackandcrackbranching.

（4）airpressuretest:

fillsealleakagesite.

（5）:

InjectionGroutinggroutinggroutingliquidpreparedbyaircompressor,0.2MPapressuregrouting,groutingmouthfromoneend,generallyfromtheadjacentGroutinggroutingliquidoverflowmouthafterstoppinggrouting,groutingandclosedmouth,inordertocarryoutthenextfilling.

（6）openmouth,closedmouthfilling.

Cast-in-situconcreteslab;crack;control;processing:

inbuildingconstruction,concreteslabcastinginsiteoftenvaryinsize,depthofthecrackphenomenon,throughtheanalysisofcracksincast-in-placeconcretefloorperformancestatus,revealsthecausesofcracks,andputsforwardhowtocontrolthefundamentalmeasuresofpreventionandtreatment.

Oneoftheimportantproblemsofcrackscontrolofreinforcedconcreteconstruction,cast-in-placeconcretefloorcrackisoneofthemostdifficultproblemsintheconstructionofrecognized,thesecracksnotonlyaffectstheappearanceofthebuilding,andtheinfluenceofthebuildingusefunction,greatlyreducesthedurabilityofbuildingstructure;destructionofstructuralintegrity,reducethestiffness;

Rebarcorrosion.Sohowtosolvethecommonconcretecracks,designersandconstructionpersonnelcannotbeignored.Acrack,inclinedcrackperformance:

distributionintheflooroftheroomonthecornerofthehousingwallcracks,general45ooblique,sometimesacornertwocracksappearatthesametime,basicallytocrackdownthrough.Asasevenstoreyframeresidentialbuildingproject,thetotallengthofthestructureisabout100m,equippedwithtwotemperaturejoint,thesideofthebasefortherestofstripfoundationandindependentfoundationslab.Inabouttwomonthsafterthehandoversuddenlyfoundononespancolumnplateaturrettemperaturecracks45.Cracks,fromthreelayerstosixfloorseachhave3,butnotthroughthefloor.

Theverticalandhorizontalcracks:

mainlyforthelongitudinalandtransversecracks.Asateachingbuilding,thecast-in-placereinforcedconcreteflooroflargeareawidthof0.10.3mmrangingfromlongitudinalandtransversecracks.

Thesurfacecracks:

suchcracksmainlycracksintheconstructionprocess,easycontrolandtreatment.Asaprojectunderconstruction,becausethesurfaceareaislarge,intheeveningpouredconcrete,themorningoftheseconddayforwatering,butbeforepouringbacktokill,surfacecracksappearedatnoon,withthenakedeyecanidentify.Effectoftworeasons,concretefloorcrack1.concretematerials

TheeffectofcementcementshrinkagevaluedependsontheC3A,likeSO3,gypsumcontentandfinenessofcementetc..ThecontentsofC3A,thefinenessoffinecementshrinkage.Thecontentofgypsuminsufficientcement,hasalargercontraction,whilethecontentofSO3ontheinfluenceofconcreteshrinkagesignificantly.

Theinfluenceofaggregate:

withtheincreaseofthecontentofaggregateconcreteshrinkagedecreaseswiththeincreaseofaggregateelasticmodulusdecreases,atthesametime,andincreasedwiththeincreaseofclaycontentinaggregate.Inaddition,intheconcrete,theaggregategradationisnotveryreasonableisthemainfactorscausingcracksinconcrete.

Theinfluenceofconcretemixratio:

includingunitwater,cementcontent,watercementratio,sandratioandmortarratio.Intheunitwateruseanddosageofcementconcreteshrinkagedepends,andwatereffectsthanthecementcontent;inwaterundercertainconditions,shrinkageincreaseswiththeincreaseofthedosageofcementdryconcrete,butincreasedinthemassratio;undercertainconditions,shrinkageincreaseswiththeincreaseofwatercementratiosignificantlyincreaseddryconcrete;mixinthesameconditions,thedryshrinkagerateincreaseswiththeincreaseofsandconcrete,buttoalesserextent.

Theadditivetypeandcontent:

theinfluenceofmixedwithchemicaladmixturescanmaketheshrinkageofconcreteincreases.Superplasticizerusedtoimproveconcreteworkability,increaseslump,superplasticizerconcreteisgreaterthanthenondopedchargeshortening