1、Designation:C231/C231M17aStandard Test Method forAir Content of Freshly Mixed Concrete by the PressureMethod1This standard is issued under the fixed designation C231/C231M;the number immediately following the designation indicates the yearof original adoption or,in the case of revision,the year of l
2、ast revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This test method covers determination of the air contentof freshly mixed concrete from observation of the change involume
3、of concrete with a change in pressure.1.2 This test method is intended for use with concretes andmortars made with relatively dense aggregates for which theaggregate correction factor can be satisfactorily determined bythe technique described in Section 6.It is not applicable toconcretes made with l
4、ightweight aggregates,air-cooled blast-furnace slag,or aggregates of high porosity.In these cases,TestMethod C173/C173M should be used.This test method is alsonot applicable to nonplastic concrete such as is commonly usedin the manufacture of pipe and concrete masonry units.1.3 The text of this test
5、 method references notes andfootnotes that provide explanatory information.These notesand footnotes(excluding those in tables and figures)shall notbe considered as requirements of this standard.1.4 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The
6、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.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with it
7、s 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 prolon
8、ged exposure.2)1.6 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 Techni
9、calBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:3C31/C31M Practice for Making and Curing Concrete TestSpecimens in the FieldC138/C138M Test Method for Density(Unit Weight),Yield,and Air Content(Gravimetric)of ConcreteC143/C143M Test Method for Slump of Hydraulic-CementCon
10、creteC172/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 LaboratoryC670 Practice for Preparing Precision and Bias Statementsfor Test Meth
11、ods for Construction Materials3.Significance and Use3.1 This test method covers the determination of the aircontent of freshly mixed concrete.The test determines the aircontent of freshly mixed concrete exclusive of any air that mayexist inside voids within aggregate particles.For this reason,itis a
12、pplicable to concrete made with relatively dense aggregateparticles and requires determination of the aggregate correctionfactor(see 6.1 and 9.1).3.2 This test method and Test Method C138/C138M andC173/C173M provide pressure,gravimetric,and volumetricprocedures,respectively,for determining the air c
13、ontent offreshly mixed concrete.The pressure procedure of this testmethod gives substantially the same air contents as the othertwo test methods for concretes made with dense aggregates.3.3 The air content of hardened concrete may be eitherhigher or lower than that determined by this test method.Thi
14、s1This test method is under the jurisdiction of ASTM Committee C09 onConcrete and Concrete Aggregates and is the direct responsibility of SubcommitteeC09.60 on Testing Fresh Concrete.Current edition approved April 15,2017.Published June 2017.Originallyapproved in 1949.Last previous edition approved
15、in 2017 as C231/C231M 17.DOI:10.1520/C0231_C0231M-17A.2Section 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
16、of ASTMStandards volume information,refer 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 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 Recommenda
