1、Designation:C42/C42M16American Association StateHighway and Transportation Officials StandardAASHTO No.:T24Standard Test Method forObtaining and Testing Drilled Cores and Sawed Beams ofConcrete1This standard is issued under the fixed designation C42/C42M;the number immediately following the designat
2、ion indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies
3、of the U.S.Department of Defense.1.Scope*1.1 This test method covers obtaining,preparing,and test-ing cores drilled from concrete for length or compressivestrength or splitting tensile strength determinations.This testmethod is not applicable to cores from shotcrete.NOTE1Test Method C1604/C1604M is
4、applicable for obtaining,preparing,and testing cores from shotcrete.NOTE2Appendix X1 provides recommendations for obtaining andtesting sawed beams for flexural performance.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach s
5、ystem 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 The text of this standard references notes and footnotesthat provide explanatory material.These notes and footnotes
6、(excluding those in tables and figures)shall not be consideredas requirements of the standard.1.4 This standard does not purport to address the safetyconcerns,if any,associated with its use.It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and d
7、etermine the applicability of regulatorylimitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C39/C39M Test Method for Compressive Strength of Cylin-drical Concrete SpecimensC78/C78M Test Method for Flexural Strength of Concrete(Using Simple Beam with Third-Point Loading)C174/C174M Test
8、 Method for Measuring Thickness of Con-crete Elements Using Drilled Concrete CoresC496/C496M Test Method for Splitting Tensile Strength ofCylindrical Concrete SpecimensC617/C617M Practice for Capping Cylindrical ConcreteSpecimensC642 Test Method for Density,Absorption,and Voids inHardened ConcreteC6
9、70 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsC823/C823M Practice for Examination and Sampling ofHardened Concrete in ConstructionsC1231/C1231M Practice for Use of Unbonded Caps inDetermination of Compressive Strength of Hardened Cy-lindrical Concr
10、ete SpecimensC1542/C1542M Test Method for Measuring Length of Con-crete CoresC1604/C1604M Test Method for Obtaining and TestingDrilled Cores of Shotcrete3.Significance and Use3.1 This test method provides standardized procedures forobtaining and testing specimens to determine the compressive,splitti
11、ng tensile,and flexural strength of in-place concrete.3.2 Generally,test specimens are obtained when doubtexists about the in-place concrete quality due either to lowstrength test results during construction or signs of distress inthe structure.Another use of this method is to provide strengthinform
12、ation on older structures.3.3 Concrete strength is affected by the location of theconcrete in a structural element,with the concrete at the bottomtending to be stronger than the concrete at the top.Corestrength is also affected by core orientation relative to thehorizontal plane of the concrete as p
13、laced,with strengthtending to be lower when measured parallel to the horizontal1This 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 Oct.1,2016.Publi
14、shed October 2016.Originallyapproved in 1921.Last previous edition approved in 2013 as C42/C42M 13.DOI:10.1520/C0042_C0042M-16.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,ref
15、er to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 plane.3These factors shall be considered in planning thelocation
16、s for obtaining concrete samples and in comparingstrength test results.3.4 The strength of concrete measured by tests of cores isaffected by the amount and distribution of moisture in thespecimen at the time of test.There is no standard procedure tocondition a specimen that will ensure that,at the time of test,it will be in the identical moisture condition as concrete in thestructure.The moisture conditioning procedures in this testmethod are intended to provide reproducible moisture condi-tions
