外文翻譯-淺談混凝土的施工過程中溫度與裂縫控制

外文翻譯一、原文DiscusstheconstructiontemperatureandcrackoftheconcretelightlyThesummary:Inordertopreventtheownersoftheconcreteworkofclaims,wemustdoagoodjobintheconstructionprocessinthetemperatureandcrackcontrol,throughobservationliveformanyyears,throughconsultingthemonographaboutstresswithintheconcrete,explaintoconcretetemperaturereason,on-the-spotconcretecontrolandmeasure,preventionofcrackoftemperaturethatcrackproduce.KeywordConcreteTemperaturestressCrackControl1.Theconcreteoccupiestheimportantpositioninmodernengineeringconstruction.Buttoday,thecrackoftheconcreteiscomparativelygeneral,thecracksarenearlyomnipresentinthescienceofbridgebuilding.Thoughwetakevariouskindsofmeasuresinconstructing,careful,butthecrackstilloccursnowandthen.Tracingittoitscause,itisoneofthemincompletelythatourchangetoconcretetemperaturestresspaysattentionto.Inthelargevolumeconcrete,temperaturestressandtemperaturecontrolaresignificant.Thisismainlybecauseofthereasonoftworespects.Firstofall,concreteoftenappearthetemperaturecrackinnotconstructing,influencetheglobalityanddurabilityofthestructure.Secondly,inthecourseofoperating,thetemperaturechangehasremarkableinfluencethatcan'tbeignoredonthestressstateofthestructure.Wemeettoconstructtemperaturecrackinmainly,soonlytoorigincauseofformationandtreatmentmeasure,concreteofcrackmakeadiscussioninconstructingthistext.ReasonofacrackIthasmanykindsofreasonstoproducethecrackintheconcrete,itismainlythechangesoftemperatureandhumidity,fragilityanddisparityoftheconcrete,andthestructureisunreasonable,therawmaterialsisnotuptostandard(ifthealkaliaggregatereact),thetemplateisoutofshape,thefoundationdoesnotsubsideetc.evenly.Thecementemitsalargeamountofheatofhydrationwhentheconcreteishardened,insidetemperatureisrisingconstantly,causethestressofdrawingonthesurface.Inthecourseofloweringthetemperature,isitcongealfoundationpayrestraintomixalwayslaterstage,willpresentthestressofdrawingwithintheconcrete.Reducingoftemperaturecansurfacecauseheavystressofdrawingveryinconcretetoo.Whenthesedrawthestressandgobeyondresistingtheabilityofsplittingofconcrete,namelywillpresentthecrack.Alotofinsidehumidityofconcretechangeverylightorchangerelativelyslow,surfacehumiditymightchangeheavytheviolentchangetakesplacing.Suchasmaintainingthoroughly,whengettingwetterwhennotdoing,contractsurfacetherearen'tdeformationdoing,oftencausethecracktoo.Theconcreteisakindoffragilitymaterial,tensilestrengthisabout1/10ofthecompressionstrength,isitcarryonone'sshoulderorbacklimitwhendrawoutofshapetohave（0.6～1.0）×104only,isitcarryonone'sshoulderorbacklimitlocationwhenstretchoutofshapetothereis（1.2～2.0）×104toaddforalongtimetoaddashorttime.Becauserawmaterialseven,waterdustthanunstable,transportandbuildphenomenonofemanatingofcourse,itstensilestrengthisnoteveninthesameconcrete,alotofresisttheabilityofdrawingverylow,itisapttopresenttheweakpositionofthecrack.Amongarmoredconcrete,drawstresstoundertakebyreinforcingbarmainly,concretebearstressofkeepingjust.Orreinforcingbarmixifedgepositiongonetocongealpresentsthestressofdrawinginthestructureinplainconcretemustrelyontheconcreteoneselftobear.Requireavoidingthestressofdrawingoronlyverysmallstressofdrawingappearsofthegeneraldesign.Buttheconcreteiscooledfrommaximumtemperaturetothesteadytemperatureofoperatingperiodinconstructing,oftencausesizabletodrawthestresswithintheconcrete.Thetemperaturestresscanexceedotheroutsidesandloadthestressescausedsometimes,knowchangelaw,temperatureofstressforcarryonreasonablestructuraldesignandconstructextremelyimportant.Analysisof2temperaturestressesItcanbedividedintofollowingthreestagesaccordingtotheformingprocessofthetemperaturestress:(1)Itisearly:Itneedsgenerally30dayfrombeginningbuildingconcretetofinishingsendingoutheatbasicallybycement.Therearetwocharacteristicsatthisstage,first,thecementemitsalargeamountofheatofhydration,second,mixandcongealthechangingsharplyofelasticmodelquantity.Becauseofthechangeofelasticmodelquantity,formtheremainingstressintheconcreteinthisperiod.(2)Middleperiod:Uptilltheconcreteiscooleduntilstabilitytemperaturefromcementsendoutheatfunctionbasicallywhenexpiring,inthisperiod,thetemperaturestressismainlybecausethecoolingoftheconcreteandexternaltemperaturechangecause,thesestressesandremnantsstressesthatisformedinearlydaysaresuperposed,mixandcongealtheelasticmouldamountthatgoestoanddoesnotchangemuchduringthisperiod.(3)Laterperiod:Operationperiodafterthecompletecoolingofconcrete.Temperaturestresswhetherexternaltemperaturechangecausesmainly,thesestressesandfirsttwokindsofremnantsstressesarechangedandadded.Itcanbedividedintotwokindsaccordingtothereasonwhythetemperaturestresscauses:(1)Spontaneousstress:Therearenotanyrestraintsortotallystaticstructureattheborder,ifinsidetemperatureisnon-lineardistribution,temperaturestressappearingbecausestructurerestrainsfromeachother.Forexample,thebodyofmoundofthebridge,thephysicaldimensionisrelativelylarge,surfacetemperatureislowwhentheconcreteiscooled,insidetemperatureishigh,presentthestressofdrawingonthesurface,presentthestressofpressinginthemiddle.(2)Restrainthestress:Allofthestructureonesoritrestrainexternalonesomeborder,can'toutofshapeandstressnotcausenotfree.Suchascasebeamroofconcreteandguardrailconcrete.Thesetwokindsoftemperaturestressesdrawbackstressescausedtoactonwiththedoingofconcretetogetherfrequently.Itisamorecomplicatedjobtowanttoanalysethedistribution,sizeofthetemperaturestressaccuratelyaccordingtoknowntemperature.Incaseofgreatmajority,needtorelyonthemodeltestorthenumbervaluetocalculate.Toisitmaketemperaturestresshavesizablelimptocreepconcrete,atthestressaccountingtemperature,mustconsidertheinfluencethatcreep,calculateconcretelythatnolongerstatesthinlyhere.Controlandpreventingthemeasureofthecrackof3temperatureForpreventcrack,lightentemperaturestresscanfromcontroltemperatureandisitisitsetabouttorestraintermsfromtwotoimprove.Themeasureofcontrollingtemperatureisasfollows:(1)Isitimproveaggregategrademix,isitdorigidconcretetospend,mixmixturetoadopt,isitguideangrypharmaceuticalorplastificationpharmaceutical,etc.measureinordertoreducecementconsumptionofconcretetoadd;(2)Addwaterorthewatertocoolthebrokenstoneinordertoreducethetemperatureofbuildingoftheconcretewhilemixingandshuttingtheconcrete;(3)Reducethethicknessofbuildingwhilebuildingtheconcreteonhotday,utilizeandbuildtheaspecttodispeltheheat;(4)Burythewaterpipeundergroundintheconcrete,enterthecoldwatertolowerthetemperatureopenly;(5)Stipulaterationalformremovaltime,thetemperaturekeepswarmthesurfacewhileloweringsuddenly,incasethattherapidtemperaturegradienttakesplaceintheconcretesurface;(6)Theconcretewithmediumandlong-termandexposedconstructionbuildsapieceofsurfaceorthinwallstructure,takethemeasureofkeepingwarmincoldseason;Themeasureofimprovingconditionofrestrainingis:(1)Divideandsewanddivideonerationally;(2)Preventthefoundationfromrisingandfallingtoobig;(3)Rationalarrangementconstructionprocess,preventthetoobigdiscrepancyinelevationandsidefromexposingforalongtime;Inaddition,improvetheperformanceoftheconcreteandimproveandresisttheabilityofsplitting,strengthenmaintenance,preventthesurfacefrombeingdoneandcontracted,especiallyguaranteethequalityoftheconcreteisveryimportanttopreventingthecrack,shouldpayspecialattentiontoavoidingproducingandrunningthroughthecrack,theglobalityresumeditsstructureafterappearingisverydifficult,soshouldrelymainlyonpreventingtheemergenceoftherunningthroughcrackwhileconstructing.Inconstructionofconcrete,forraiseturnoverrateoftemplate,demandconcreteformremovalassoonaspossiblethatbuildnewlyoften.Shouldconsiderformremovaltimeproperlywhenconcretetemperatureishigherthanthetemperature,soasnottocausethesuperficialearlycrackofconcrete.Buildingtheearlyformremovalnewly,causeverylargestressofdrawingonthesurface,thephenomenonthat"temperatureisassaulted"appears.Buildinitialstageinconcrete,becauseheatofhydrationissentout,thesurfacecausessizabletodrawthestress,surfacetemperatureisalsohigherthantemperatureatthismoment,removethetemplateatthismoment,surfacetemperatureisloweredsuddenly,mustcausetemperaturegradient,thusaddanddrawthestressonthesurface,changeandaddwiththeheatofhydrationstress,inaddition,theconcretedriesandcontracts,thesuperficialstressofdrawingreachesverygreatnumbervalue,havedangerofcausingthecrack,butcoveralight-dutyheatinsulatorwithonthesurfaceintimeafterremovingthetemplate,forinstancefoamsponge,etc.,forpreventconcretesurfacefromproducethetoobigstressofdrawing,haveremarkableresults.Addmuscleinfluencetolargevolumetemperaturestressofconcreteverylight,becauselargevolumeconcreteincludemuscletoberateverymuchlow.Justhaveinfluenceonthegeneralarmoredconcrete.Ontermsthattemperatureisnotveryhighandthestressislessthanlimitofsurrendering,everyperformanceofthesteelissteady,andhavenothingtodowithstressstate,timeandtemperature.Linebloatedcoefficientofsteelandconcretelinebloatedcoefficientdifferenceverylight,takeplacelittleinternalstressveryonlybetweenthetwowhilechangingintemperature.Becauseelasticmouldamountofsteelconcreteelasticmould7~15ofquantity,reachasinteriorconcretestresstensilestrengthandwhenfracturing,thestressofthereinforcingbarwillnotexceed10000kg/cm2.Soisitisitpreventtinyappearancedifficultyverymuchofcrackfromtomakeuseofreinforcingbartowantamongconcrete.Butthecrackinthestructuregenerallybecomesnumerous,theintervalislittle,thewidthanddeptharesmallerafteraddingthemuscle.Andifdiameterofreinforcingbardetailedandwhenintervaldense,toimproveconcreteresistresultofpersonwhosplitbetter.Concreteandsurface,armoredconcreteofstructurecantakeplacedetailedandshallowcrackoften,amongthemthegreatmajoritybelongtoanddoanddrawbackthecrack.Thoughthiskindofcrackisgenerallyallrelativelylight,itstillshavecertaininfluenceontheintensityanddurabilityofthestructure.Inordertoguaranteeconcreteprojectquality,preventfracturing,improvethedurabilityoftheconcrete,usetheadmixturetoreduceoneofthemeasuresthatfracturescorrectly.Whetherisitreducewaterisitsplitpharmaceuticaltodefend,Isummarizehismainfunctioninpracticetouse.(1)Thereisalargenumberofcapillaryintheconcrete,producecapillarytensioninthecapillaryafterwaterisevaporated,makeconcreteisitcontractoutofshapetodo.Increasingthethinapertureofhaircanreducethecapillarysurfacetension,butwillmaketheintensityofconcretereduce.Thissurfacetensiontheoryhasalreadybeenconfirmedintheworldasfarbackasthesixties.(2)Waterdustthaninfluenceimportantfactorthatconcreteshrink,isitreducewaterisitsplitpharmaceuticalcanmakeconcretewaterconsumptionreduceby25%todefendtouse.(3)Cementconsumptionimportantfactor,concreteofpersonwhoshrinktoo,isitaddandsubtractwaterisitsplitconcretereducible15%ofthecementconsumptionontermsthatkeeptheintensityofconcreteofpharmaceuticaltodefendtomix,itsvolumeissupplementedbyincreasingaggregateconsumption.(4)Reducewaterisitsplitpharmaceuticalcanimproveconsistencyofgrout,reduceconcretesecreteinktodefend,reduceandsinkanddrawbackdeforming.(5)Improvegluingthestrengthofformingofthegroutandaggregate,theconcreteimprovedresiststheperformanceofsplitting.(6)Concreteisitproducestressofdrawingtorestrainfromwhileshrinking,crackwhendrawingthestressandisgreaterthanconcretetensilestrengthcanproduce.Reducewaterisitsplitpharmaceuticaleffectiveconcretetensilestrengthofimprovementverytodefend,improveresistingtheperformanceofsplittingofconcretebyawidemargin.(7)Itcanmaketheconcretedensitygoodtoaddtheadmixturetomix,canimproveresistingcarbonizationofconcreteeffectively,reducecarbonizationtoshrink.(8)Isitreducewaterisitsplitslowcoagulationtimeproperconcreteunderpharmaceuticaltodefend,onthebasisofpreventingthefastwaterofcementfromsendingoutheateffectivelytomix,preventtheplasticityshrinkthatbringsbecausethecementisnotcongealedforalongtimefromincreasing.(9)Mixadmixtureconcreteandgettingeasyandkind,surfaceeasytofeelflat,formlittlemembrane,reducethemoisturetoevaporate,reducedrilyandshrink.Alotofadmixturesallhavethefunctionsofslowcoagulation,increasingandapt,improvementplasticity,theexperimentthatweshouldcarryoninthisrespectmoreintheprojectpracticeiscomparedwithandstudied,thanleanagainstnotimprovingtermsmoresimple,maygettingsimpleandmoredirect,economy.Earlymaintenanceof4concretePracticehasproved,thecommoncrackofconcrete,mostisthesurfacecrackofdifferentdepth,mainreasonitswhethertemperaturegradientcausecoldtemperatureofarealowertooeasytoformcracksuddenly.Sosaythewarm-keepingoftheconcreteisespeciallyimportanttopreventingtheearlycrackofsurface.Fromtheviewpointoftemperaturestress,shouldreachandrequirekeepingwarmfollowing:1)Preventconcreteinternalandexternaltemperaturepoorandconcretesurfacegradientfrom,preventthesurfacecrack.2)Preventconcretefromtobeultraandcold,shouldisitisitmaketheminimumtemperatureisnotlowerthanthesteadytemperatureofconcreteservicetimeconstructiontimeinconcretetotrytotryone'sbest.3)Preventtheoldconcretesubcooling,inordertoreducetherestraintamongtheoldandnewconcrete.Theearlymaintenanceoftheconcrete,themainpurposeliesinkeepingthesuitablewarmandhumidcondition,inordertogettheresultoftworespects,ontheotherhandmaketheconcreteavoidtheinvasionandattackoftheunfavorableandwarm,humidityoutofshape,theonesthatpreventfromharmfullyarecoldtocontractanddotocontract.Ononehandmakecementwaterfunctiongoonsmoothly,isinthehopeofreachingtheintensitydesignedandresistingtheabilityofsplitting.Thesuitablewarmdampconditionisinterrelated.Mixwarm-keepingmeasurepaidtocongealoftenprotectswetresultstoo.Analyse,waterconcreteincludemoisturecanmeetdemand,cementofwaterhaveenoughandtosparenewlytheoretically.Butbecausethereasonofevaporatingetc.oftencauseslossesofthemoisture,thuspostponeorhinderwaterofthecementfrom,thesurfaceconcretereceivesthiskindofadverseeffecteasiestlyanddirectly.Keyperiodwhenmaintainedininitialafewdaysaftersotheconcreteisbuiltshouldpayattentiontoconscientiouslyinconstructing.2.QualitycontrolofwaterproofconcreteconstructionCombinedwithexperience,fromformworkdesign,fabricationandinstallation,assemblingreinforcement,pouringandcuringofconcreteandotheraspectsconstructiontechnologyoffair-facedconcreteisintroducedaswellasqualitycontrolmeasuresandstandardsinordertoreduceengineeringcosttoacquiresatisfiedeconomicandsocialbenefits.Thefactorsofinfluencingwaterproof-concretequalityareverymany.Anylinksdoesnotpayattentiontothewater-proofconcreteoffieldlosshindersthewaterfunctionwithoutexceptionjointlywithdegree.Engineeringconstructioninthebasementadoptssecondaryformboardfabricationandinstallation,reinforcedbarfabricationandbind,concretestirringandmixingsystemandtransport,concretecovibrationbeatwithastick,constructionjointpractice,concretecuringanddismantlemodelandbeingreadyforbackfillandsoonaspects.Theseareverycriticaltoqualitymethodtoensurethatwater-proofconcreteselfwater-proof,andthewayofpracticehaswanout.Methodbeingunderconstruction2.1FabricationandInstallationAccordingtotheconcertofcloselyknit,demandofreasonwhytoformboardsincethewater-proofalsoconcretehavemadeandhaveassembledcorrespondingriseisspecial,betorequirethatnotleavingoutthickfluid,firmcloselyknitblockofwooddeformation,waterabsorptionCharactershouldbesmallandoughttogiveprioritytoselectandusingbambooslabrubberformboardorthesteelform..Strictcontrolformboardroomgapsize,necessaryexceeding2mmsusesfoamrubberorplastictosqueezeacrackin,porousformboardnonutilitywithoutexceptiontoboardfaceBereadyforwallpostatthesametimerottingthepreventionandcurejobadoptthecementmortarpouringsame,indiciainbeforetherootsegmentstickingthefoamrubberorplasticstrip,thebottomputsonacementmortar,concreteaconcrete,first5cm~10cm.Sincewater-proof,concretestructurewallthicknessismostlymoreinfertile.Betoensurethatcomponentgeometrydimension,Changadopttheinsideandoutsidebolttopullthemeasuremeetingattentionto,respondstoonplayreceiveboltcentreinterposestopwaterironplate,topreventwaterfromformingpilotagepassagealongboltleakage.2.2AssemblingreinforcementWater-proofconcretestructurehasdemandingasfollowstothereinforcedbar:1)Reinforcedbarshouldadopttwistedsteelasfaraspossible,increasesbyholdwrapaforcecomposinginreplyawaterability2)Reinforcedbarsconnectshouldtryone'sbesttoadopttosolderconnection,stopusingandbeingneedlesstobindconnectiontothefull3)Whenbindingareinforcedbar,theironwireheadrespondstoinnerbending.4)Strictcontrolreinforcedbarsprotectivelayerthickness.Minimalthicknessofwater-proofconcretereinforcedbarprotectivelayerisnotsmallerthan25mms,theprotectivelayerwelcomingwatersurfaceespeciallyinadmissibilitytodisappointerror.Theironwireandreinforcedbarthatapplicationburiesinadvancewithinmortarpiecewhileusingmortarheelblockasprotectivelayer,areboundsolid.Whenthecavalryputsupthefixedreinforcedbarifadoptareinforcedbar,alsoneedtoincreasesolderswaterironplateorfixationjustgoesahead,tostrengthenwater-proofeffectintheheelblock.Thisprojectusesnewmaterialsnylontohavefixedthereisaneffect'shadguardedagainstreinforcedbarprotectivelayerdeviationpiecebigmasscommonfailings.2.3TheconcretestirringandmixingmakesandtransportsSincethewater-proofconcreterequiresthathighercloselyknit,reasonwhystirandmixsystemalsoneedtohavethefairlygoodhomogeneity,shouldbereadyforburningasfollowsalmostforthispurpose:1)Ensuresthatmixingtime,mixingateverytimearesecondaryjumpintoaexpectthegeneralejectionofcompactblockofwoodlessthan2mins.2)Shouldusetheappositionagent,thesolutionqueenwhoshouldmanufacturecertainthicknessfromappositionagentaddsthemixerinner,thedriedpowderorhighconcentrationsolutionwilladdanagentextranottoaddsthemixerinnerdirectly,preventfrommixingisunevenbutpartconcentrates,bothlosetheappositionagenteffect,andaffectconcretemass.3)Respondstotheassuredsourceoflifedegreehavingaspottestontheadmeasurementconcreteattheregularintervalscollapsingintheprocessbeingunderconstruction,constructionismiddleifYurainsorothercause,respondtotheratiodeterminingwhosewaterratio,andadjustingthecompositionbeingunderconstructionintimewhenchangehappenedinsandstonemoisturecontent.4)Projectusesthecommodityconcrete,hasboundaryhaveraisedaconcretestirringmassandofallkindseffectappositionagentadulteratingfallswhenamounts,thewaterashhavingcontrolledaconcretestrictlycollapsing.5)Concretesadoptapumptohavegivenhandicraft,effectiveavoidingaconcreteproducingthephenomenonisolatingbleedingandleavingoutthickfluidintheprocessoftransportation.2.4Mattersneedingattentioninbeingunderconstruction1)Constructionschoolassignmentsoftandflouryisdivided.Water-proofconcretingshouldstratifystrictlybeinginprogress,andacontinuousconstructioniscompletedThefrontandbackandhighandlowconnectbetweenthetiershouldsubjugatewithinthecementinitialsettingtime,Forthispurpose,withhandlingaworkerdividingintoseveral,atthesametimeeachother,schoolassignmentgroupfacesoritisallrightforeachother,carryontheback.2)AchievestrictlyfixedpointdeterminestheamountsofthecomponentsofasubstancematerialdownAccordingtothevehiclecapacitiesstratifyingconcretealtitudeandthemeansoftransport,thequantifycarryingoutfixedpointstrictlyisabletogodownoneimportantringexpectingthatthisistoimprovewater-proofconcretingmass.3)Concretesvibratingbeatoneimportantringbeingtoensurethattheconcreteiscloselyknit,defendagainsttoseepwithastick.Also,shouldadoptfixedpointvibrating,handlemeticulouslyonbasisexpectingthatunderdeterminingtheamountsofthecomponentsofasubstancehomogeneouslyinfixedpoint.Payattentiontohighandlowtieroflinkingup.Nowthatneedingtopreventfrommissandvibrating,notvibratingenough,beinggoingtopreventafaultfromvibratingagain,Needtoforbidusingpryingthemethodcomingtoaidtovibratemovingareinforcedbarorshakingareinforcedbarespecially,suchseparatestomakingthefrontalreadyconcretethereinforcedbarandconcreteshakingtherealitypart,causesseriousconsequences.4)Beingreadyfortheassuredsourceoflifedegreetakingoverthickfluidmeasure,andadjustingintimetocollapseseriously.Averagewater-proofconcretestructureconstruction,theconstructionjointbeingunderconstructionrespectively,composingnamelyonerectingwallsellsbebottomboardandverticalwallatreducedprices.Shouldirrigatethickalayerof5cm~10cmssurnameindiciacementmortarsinseamplacefirstlinkingupcloselyknittingtier,inordertoensuringthattheseamplacevibrateswhenconcreteverticalwall.Simultaneous,improvestepbystepwithconcreteanaltitude,shouldfalloffstepbystepwiththewateryield,diminishcollapsingtofalldegreepreventfromconcreteinsisttobeshortbutthecementpasteispartialtomuchphenomenontoaggregateappearingonupperpart.2.5DismantlingmodelandcuringofconcreteThewater-proofconcretingqueenmaintainsgoodnessandbadnessworking,notonlyaffectingtheintensityarrivingataconcrete,moreovertheimperviousfunctionaffectingtotheconcrete.Evidence,water-proofconcreteearlyphasedehydrationorcuringprocesslackforwater,willreducewhoseimperviousfunctionbyawidemargin.Water-proofconcretecuringrespondstotheblockofwoodlessthan14ds.Thewater-proofconcretedismantlesamodeldemandingtobeunabletocomparehigh,dismantlemodeltimeunsuitableuntimely,respondtowhendismantlingamodelhandlemeticulously,preventanironrodfromusingtoprystiffly,thatthesledgehammerisknockedsuddenlyandforciblypries,usesaconcretemeetwithdestroy.2.6DogoodwellatbackfillWater-proofarchitecturalbackfillisafinalworkingprocedure,itbesometimesignored,thisisaverybigfaultsinfactundertheground.Whenthewater-proofstructurejobisoverqueenrespondstotheconstructioncarryingoutbackfillimmediately.Mostimportant,weshouldtakebackfillseriouslyselfmass;Secondly,backfillvariaandpondingshouldclearupthepitbottominthefront,respondtodensificationwithlayerswhenbackfill.Water-proofstructurevicinitylayerpoundstruebackfill,selfisareliableandeconomicalaswellwaterproofingdraperyundertheground.InprojectbasementengineeringconstructionShanghai,sinceorganizingwaterproofingdowntoearthstrictlywithallabovesevenpasses,theconcreteisunderconstruction,effectiscomparativelyideal.Thepercolatingwaterphenomenondoesnotappear.ConclusionsConstructiontemperatureandrelationofcrackinconcretetheabovecarryonpreliminarydiscussionoftheoryandpractice,thoughtheacademiahasdifferenttheoriestoorigincauseofformationandcomputingtechnologyoftheconcretecrack,buttoconcretepreventionandimprovingthemeasuresuggestiontorelativelyunify,applicationinpracticeresultfinetooatthesametime,concretetoisitobserve,comparemorebyustowantinconstructing,analysemore,summarizemoreaftergoingwrong,combinemanykindsofpreventionanddealwiththemeasure,thecrackoftheconcretecanbeavoided.翻譯淺談混凝土的施工過程中溫度與裂縫控制摘要為了防止業(yè)主對混凝土工程的索要賠償,我們就必須做好過程中的溫度與裂縫控制。本文通過多年的現(xiàn)場觀察，通過查閱有關(guān)混凝土內(nèi)部應(yīng)力方面的專著，對混凝土溫度裂縫產(chǎn)生的原因、現(xiàn)場混凝土溫度的控制和預(yù)防裂縫的措施進(jìn)行等進(jìn)行闡述。關(guān)鍵詞：混凝土溫度應(yīng)力裂縫控制1.混凝土在現(xiàn)代工程建設(shè)中占有重要地位。而在今天，混凝土的裂縫較為常見，在橋梁工程中裂縫更多。盡管我們在施工中采取各種措施，但裂縫仍然時(shí)有出現(xiàn)。究其原因，我們對混凝土溫度應(yīng)力的變化注意不夠是其中之一。在大體積混凝土中，溫度應(yīng)力及溫度控制具有重要意義。這主要是由于兩方面的原因。首先，在施工中混凝土常常出現(xiàn)溫度裂縫，影響到結(jié)構(gòu)的整體性和耐久性。另外，在運(yùn)轉(zhuǎn)過程中，溫度變化對結(jié)構(gòu)的應(yīng)力狀態(tài)具有顯著的不容忽視的影響。我們遇到的主要是施工中的溫度裂縫，因此本文僅對施工中裂縫的成因和處理措施做一探討。1）裂縫的原因混凝土中產(chǎn)生裂縫有多種原因，主要是溫度和濕度的變化，混凝土的脆性和不均勻性，以及結(jié)構(gòu)不合理，原材料不合格（如堿骨料反應(yīng)），模板變形，基礎(chǔ)不均勻沉降等?；炷劣不陂g水泥放出大量水化熱，內(nèi)部溫度不斷上升，在表面引起拉應(yīng)力。后期在降溫過程中，由于受到基礎(chǔ)或老混凝上的約束，又會(huì)在混凝土內(nèi)部出現(xiàn)拉應(yīng)力。氣溫的降低也會(huì)在混凝土表面引起很大的拉應(yīng)力。當(dāng)這些拉應(yīng)力超出混凝土的抗裂能力時(shí)，即會(huì)出現(xiàn)裂縫。許多混凝土的內(nèi)部濕度變化很小或變化較慢，但表面濕度可能變化較大或發(fā)生劇烈變化。如養(yǎng)護(hù)不周、時(shí)干時(shí)濕，表面干縮形變受到內(nèi)部混凝土的約束，也往往導(dǎo)致裂縫?；炷潦且环N脆性材料，抗拉強(qiáng)度是抗壓強(qiáng)度的1/10左右，短期加荷時(shí)的極限拉伸變形只有（0.6～1.0）×104，長期加荷時(shí)的極限位伸變形也只有（1.2～2.0）×104。由于原材料不均勻，水灰比不穩(wěn)定，及運(yùn)輸和澆筑過程中的離析現(xiàn)象，在同一塊混凝土中其抗拉強(qiáng)度又是不均勻的，存在著許多抗拉能力很低，易于出現(xiàn)裂縫的薄弱部位。在素混凝土內(nèi)或鋼筋混凝上的邊緣部位如果結(jié)構(gòu)內(nèi)出現(xiàn)了拉應(yīng)力，則須依靠混凝土自身承擔(dān)。一般設(shè)計(jì)中均要求