浅论混凝土的施工过程中温度与裂缝控制.docx
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浅论混凝土的施工过程中温度与裂缝控制.docx
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浅论混凝土的施工过程中温度与裂缝控制
外文翻译
Discusstheconstructiontemperatureandcrackoftheconcretelightly
ByG.K.Kululanga,W.Kuotcha,R.McCaffer,Member,ASCE,andF.Edum-Fotwe,TheAmericanSocietyofCivilEngineers
ThesummaryThroughobservationliveformanyyears,throughconsultingthemonographaboutstresswithintheconcrete,explaintoconcretetemperaturereason,on-the-spotconcretecontrolandmeasure,preventionofcrackoftemperaturethatcrackproduce.
Keyword:
Concrete;Temperaturestress;Crack;Control
1.Theconcreteoccupiestheimportantpositioninmodernengineeringconstruction.Buttoday,thecrackoftheconcreteiscomparativelygeneral,thecracksarenearlyomnipresentinthescienceofbridgebuilding.Thoughwetakevariouskindsofmeasuresinconstructing,careful,butthecrackstilloccursnowandthen.Tracingittoitscause,itisoneofthemincompletelythatourchangetoconcretetemperaturestresspaysattentionto.Inthelargevolumeconcrete,temperaturestressandtemperaturecontrolaresignificant.Thisismainlybecauseofthereasonoftworespects.Firstofall,concreteoftenappearthetemperaturecrackinnotconstructing,influencetheglobalityanddurabilityofthestructure.Secondly,inthecourseofoperating,thetemperaturechangehasremarkableinfluencethatcan'tbeignoredonthestressstateofthestructure.Wemeettoconstructtemperaturecrackinmainly,soonlytoorigincauseofformationandtreatmentmeasure,concreteofcrackmakeadiscussioninconstructingthistext.
Reasonofacrack
Havemanykindsofreasonstoproducethecrackintheconcrete,itismainlythechangesoftemperatureandhumidity,fragilityanddisparityoftheconcrete,andthestructureisunreasonable,therawmaterialsisnotuptostandard(ifthealkaliaggregatereact),thetemplateisoutofshape,thefoundationdoesnotsubsideetc.evenly.Thecementemitsalargeamountofheatofhydrationwhentheconcreteishardenned,insidetemperatureisrisingconstantly,causethestressofdrawingonthesurface.Inthecourseofloweringthetemperature,isitcongealfoundationpayrestraintomixalwayslaterstage,willpresentthestressofdrawingwithintheconcrete.Reducingoftemperaturecansurfacecauseheavystressofdrawingveryinconcretetoo.Whenthesedrawthestressandgobeyondresistingtheabilityofsplittingofconcrete,namelywillpresentthecrack.Alotofinsidehumidityofconcretechangeverylightorchangerelativelyslow,surfacehumiditymightchangeheavytheviolentchangetakesplacing.Suchasmaintainingthoroughly,whengettingwetterwhennotdoing,contractsurfacetherearen'tdeformationdoing,oftencausethecracktoo.Theconcreteisakindoffragilitymaterial,tensilestrengthisabout1/10ofthecompressionstrength,isitcarryonone'sshoulderorbacklimitwhendrawoutofshapetohave*104only,isitcarryonone'sshoulderorbacklimitlocationwhenstretchoutofshapetothereis*104toaddforalongtimetoaddashorttime.Becauserawmaterialseven,waterdustthanunstable,transportandbuildphenomenonofemanatingofcourse,itstensilestrengthisnoteveninthesameconcrete,alotofresisttheabilityofdrawingverylow,itisapttopresenttheweakpositionofthecrack.Amongarmoredconcrete,drawstresstoundertakebyreinforcingbarmainly,concretebearstressofkeepingjust.Orreinforcingbarmixifedgepositiongonetotocongealpresentthestressofdrawinginthestructureinplainconcrete,mustrelyontheconcreteoneselftobear.Requiretoavoidthestressofdrawingoronlyverysmallstressofdrawingappearsofthethegeneraldesign.Buttheconcreteiscooledfrommaximumtemperaturetothesteadytemperatureofoperatingperiodinconstructing,oftencausesizabletodrawthestresswithintheconcrete.Thetemperaturestresscanexceedotheroutsidesandloadthestressescausedsometimes,knowchangelaw,temperatureofstressforcarryonreasonablestructuraldesignandconstructextremelyimportant.Analysisof2temperaturestressescanbedividedintofollowingthreestagesaccordingtotheformingprocessofthetemperaturestress:
(1)Itisearly:
Buildconcreteisitisitoverbasicallytosendoutheattocementtobegin,generallyoneonedaybyoneself.Twocharacteristicsatthisstage,first,thecementemitsalargeamountofheatofhydration,second,mixandcongealthechangingsharplyofelasticmodelquantity.Becauseofthechangeofelasticmodelquantity,formtheremainingstressintheconcreteinthisperiod.
(2)Middleperiod:
Uptilltheconcreteiscooleduntilstabilitytemperaturefromcementsendoutheatfunctionbasicallywhenexpiring,inthisperiod,thetemperaturestressismainlybecausethecoolingoftheconcreteandexternaltemperaturechangecause,thesestressesandremnantsstresses
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- 关 键 词:
- 混凝土 施工 过程 温度 裂缝 控制
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