ACI 308R-01 Guide to Curing Concrete

ACI308R-01becameeffectiveAugust14,2001.Copyright©2001,AmericanConcreteInstitute.Allrightsreservedincludingrightsofreproductionanduseinanyformorbyanymeans,includingthemakingofcopiesbyanyphotoprocess,orbyelectronicormechanicaldevice,printed,written,ororal,orrecordingforsoundorvisualreproduc-tionorforuseinanyknowledgeorretrievalsystemordevice,unlesspermissioninwritingisobtainedfromthecopyrightproprietors.ACICommitteeReports,Guides,StandardPractices,andCommentariesareintendedforguidanceinplanning,designing,executing,andinspectingconstruction.Thisdocumentisintendedfortheuseofindividualswhoarecompetenttoevaluatethesignificanceandlimitationsofitscontentandrecommendationsandwhowillacceptre-sponsibilityfortheapplicationofthematerialitcontains.TheAmericanConcreteInstitutedisclaimsanyandallre-sponsibilityforthestatedprinciples.TheInstituteshallnotbeliableforanylossordamagearisingtherefrom.Referencetothisdocumentshallnotbemadeincon-tractdocuments.Ifitemsfoundinthisdocumentarede-siredbytheArchitect/Engineertobeapartofthecontractdocuments,theyshallberestatedinmandatorylanguageforincorporationbytheArchitect/Engineer.308R-1GuidetoCuringConcreteACI308R-01Theterm“curing”isfrequentlyusedtodescribetheprocessbywhichhydraulic-cementconcretematuresanddevelopshardenedpropertiesovertimeasaresultofthecontinuedhydrationofthecementinthepresenceofsufficientwaterandheat.Whileallconcretecurestovaryinglevelsofmaturitywithtime,therateatwhichthisdevelopmenttakesplacedependsonthenaturalenvironmentsurroundingtheconcrete,andthemeasurestakentomodifythisenvironmentbylimitingthelossofwater,heat,orboth,fromtheconcrete,orbyexternallyprovidingmoistureandheat.Theword“curing”isalsousedtodescribetheactiontakentomaintainmoistureandtemperatureconditionsinafreshlyplacedcementitiousmixturetoallowhydraulic-cementhydrationand,ifapplicable,pozzolanicreactionstooccursothatthepotentialpropertiesofthemixturemaydevelop.Currentcuringtechniquesarepresented;commonlyacceptedmethods,procedures,andmaterialsaredescribed.Methodsaregivenforcuringpavementsandotherslabsonground,forstructuresandbuildings,andformassconcrete.Curingmethodsforseveralspecificcategoriesofcement-basedproductsarediscussedinthisdocument.Curingmeasures,ingeneral,arespecifiedinACI308.1.Curingmeasuresdirectedtowardthemaintenanceofsatis-factoryconcretetemperatureunderspecificenvironmentalconditionsareaddressedingreaterdetailbyCommittees305and306onHotandColdWeatherConcreting,respectively,andbyACICommittees301and318.Keywords:coldweather;concrete;curing;curingcompound;hotweathercon-struction;massconcrete;reinforcedconcrete;sealer;shotcrete;slab-on-ground.CONTENTSChapter1—Introduction,p.308R-21.1—Introduction1.2—Definitionofcuring1.3—Curingandthehydrationofportlandcement1.3.1—Hydrationofportlandcement1.3.2—Theneedforcuring1.3.3—Moisturecontrolandtemperaturecontrol1.4—Whendeliberatecuringproceduresarerequired1.4.1—Naturalconditions1.4.2—Sequenceandtimingofcuringstepsforunformedsurfaces1.4.3—Whencuringisrequiredforformedsurfaces1.4.4—Whencuringisrequired:coldandhotweather1.4.5—Durationofcuring1.5—Thecuring-affectedzone1.6—ConcretepropertiesinfluencedbycuringReportedbyACICommittee308DonBrognaGeneD.Hill,Jr.AimeePergalskyJosephCabrera†EdwardP.HolubWilliamS.PhelanJamesN.CornellIIR.DougHootonRobertE.Price†RonaldL.DillyKennethC.Hover*LarryR.RobertsJonathanE.DongellJohnC.HukeyPhillipSmithBenE.EdwardsFrankA.KozeliskiLukeM.SnellDerekFirthJamesA.LeeJoelTuckerJeromeH.FordDarylManuelPatrickM.WatsonSidFreedmanBryantMatherJohnB.WojakowskiGilbertJ.HaddadCalvinMcCallSamuelB.HelmsH.CelikOzyildirimStevenH.GeblerChairmanCecilL.JonesSecretary*Chairofdocumentsubcommittee†Deceased308R-2ACICOMMITTEEREPORTChapter2—Curingmethodsandmaterials,p.308R-122.1—Scope2.2—Useofwaterforcuringconcrete2.3—Initialcuringmethods2.3.1—Fogging2.3.2—Liquid-appliedevaporationreducers2.4—Finalcuringmeasures2.4.1—Finalcuringmeasuresbasedontheapplicationofwater2.4.2—Finalcuringmethodsbasedonmoistureretention2.5—Terminationofcuringmeasures2.6—Cold-weatherprotectionandcuring2.6.1—Protectionagainstrapiddryingincoldweather2.6.2—Protectionagainstfrostdamage2.6.3—Rateofconcretestrengthdevelopmentincoldweather2.6.4—Removalofcold-weatherprotection2.7—Hot-weatherprotectionandcuring2.8—Acceleratedcuring2.9—Minimumcuringrequirements2.9.1—General2.9.2—FactorsinfluencingrequireddurationofcuringChapter3—Curingfordifferenttypesofconstruction,p.308R-193.1—Pavementsandotherslabsonground3.1.1—General3.1.2—Curingprocedures3.1.3—Durationofcuring3.2—Buildings,bridges,andotherstructures3.2.1—General3.2.2—Curingprocedures3.2.3—Durationofcuring3.3—Massconcrete3.3.1—General3.3.2—Methodsanddurationofcuring3.3.3—Formremovalandcuringformedsurfaces3.4—Curingcoloredconcretefloorsandslabs3.5—OtherconstructionsChapter4—Monitoringcuringandcuringeffectiveness,p.308R-224.1—General4.2—Evaluatingtheenvironmentalconditionsinwhichtheconcreteisplaced4.2.1—Estimatingevaporationrate4.3—Meanstoverifytheapplicationofcuring4.4—Quantitativemeasuresoftheimpactofcuringproce-duresontheimmediateenvironment