ASTM_C_1768_-_C_1768M_-_12_2017.pdf

Designation:C1768/C1768M12(Reapproved 2017)Standard Practice forAccelerated Curing of Concrete Cylinders1This standard is issued under the fixed designation C1768/C1768M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice covers two procedures for making andcuring cylindrical specimens of concrete under conditions thatincrease the rate of hydration at early ages.The procedures are:AWarm Water Method and BAutogenous Curing Method.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.(WarningFreshhydraulic cementitious mixtures are caustic and may causechemical burns to skin and tissue upon prolonged exposure.2)1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:3C31/C31M Practice for Making and Curing Concrete TestSpecimens in the FieldC39/C39M Test Method for Compressive Strength of Cylin-drical Concrete SpecimensC125 Terminology Relating to Concrete and Concrete Ag-gregatesC143/C143M Test Method for Slump of Hydraulic-CementConcreteC172/C172M Practice for Sampling Freshly Mixed Con-creteC173/C173M Test Method forAir Content of Freshly MixedConcrete by the Volumetric MethodC192/C192M Practice for Making and Curing Concrete TestSpecimens in the LaboratoryC231/C231M Test Method forAir Content of Freshly MixedConcrete by the Pressure MethodC470/C470M Specification for Molds for Forming ConcreteTest Cylinders VerticallyC918/C918M Test Method for Measuring Early-Age Com-pressive Strength and Projecting Later-Age StrengthC1064/C1064M Test Method for Temperature of FreshlyMixed Hydraulic-Cement ConcreteC1231/C1231M Practice for Use of Unbonded Caps inDetermination of Compressive Strength of Hardened Cy-lindrical Concrete Specimens3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this practice,refer toTerminology C125.4.Summary of Practice4.1 Molded concrete cylindrical specimens are cured underconditions that increase the early-age concrete temperature andthe rate of hydration.This permits the specimens to develop asignificant portion of their ultimate properties within a timeperiod ranging from 24 to 49 h,depending upon the procedureused.In Procedure A,specimens are stored in a warm waterbath for 24 h.In Procedure B,specimens are stored for 48 h ininsulated curing containers in which the elevated curingtemperature is obtained from heat of hydration of the cement.If specimens are to be used for estimating strength potential inaccordance with Test Method C918/C918M,specimen tem-perature is monitored during the accelerated curing period.4.2 Table 1 summarizes important characteristics of thesecuring procedures.1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.61 on Testing for Strength.Current edition approved March 15,2017.Published May 2017.Originallyapproved in 2012.Last previous edition approved in 2012 as C1768/C1768M12.DOI:10.1520/C1768_C1768M-12R17.2See Section on Safety Precautions,Manual of Aggregate and Concrete Testing,Annual Book of ASTM Standards,Vol.04.02.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 5.Significance and Use5.1 By increasing the concrete temperature,the rate ofhydration increases and a larger portion of the later-ageproperties of the concrete can be attained during the shortcuri