ASTM_C_451_-_13.pdf

Designation:C45113Standard Test Method forEarly Stiffening of Hydraulic Cement(Paste Method)1This standard is issued under the fixed designation C451;the number immediately following the designation 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.1.Scope*1.1 This test method covers the determination of earlystiffening in hydraulic-cement paste.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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.Warning:Fresh hydraulic-cementitious mixtures are causticand may cause chemical burns to skin and tissue uponprolonged exposure.21.4 The text of this standard references notes and footnoteswhich provide explanatory material.These notes and footnotes(excluding those in tables and figures)shall not be consideredas requirements of the standard.2.Referenced Documents2.1 ASTM Standards:3C150 Specification for Portland CementC183 Practice for Sampling and the Amount of Testing ofHydraulic CementC187 Test Method for Amount of Water Required for Nor-mal Consistency of Hydraulic Cement PasteC219 Terminology Relating to Hydraulic CementC305 Practice for Mechanical Mixing of Hydraulic CementPastes and Mortars of Plastic ConsistencyC670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsC1005 Specification for Reference Masses and Devices forDetermining Mass and Volume for Use in the PhysicalTesting of Hydraulic CementsD1193 Specification for Reagent Water3.Terminology3.1 Definitions:3.1.1 early stiffening,nthe early development of stiffnessin the working characteristics of a hydraulic-cement paste,mortar,or concrete;varieties include false set and flash set.3.1.2 false set,nthe early development of stiffness in theworking characteristics of a hydraulic-cement paste,mortar,orconcrete without the evolution of much heat,which stiffnesscan be dispelled and plasticity regained by further mixingwithout addition of water;also known as“grab set,”“prema-ture stiffening,”“hesitation set,”and“rubber set.”3.1.3 flash set,nthe early development of stiffness in theworking characteristics of a hydraulic-cement paste,mortar,orconcrete,usually with the evolution of considerable heat,which stiffness cannot be dispelled nor can the plasticity beregained by further mixing without addition of water;alsoknown as“quick set.”3.1.4 Refer to Terminology C219 for definitions of otherterms.4.Summary of Test Method4.1 A paste is prepared with the cement to be tested,usingsufficient water to give a required initial penetration as mea-sured by the Vicat apparatus at a stipulated time after comple-tion of mixing.A second penetration,termed the finalpenetration,is measured at a later stipulated time.The ratio offinal penetration to initial penetration is calculated as apercentage.5.Significance and Use5.1 The purpose of this test method is to determine thedegree to which a cement paste develops early stiffening or toestablish whether or not a cement complies with a specificationlimit on early stiffening.5.2 When used for establishing compliance with a specifi-cation limit,the specification requirement is customarily statedin terms of the minimum allowable final penetration,inpercent,calculated in accordance with the Calculation Section.1This test method is under the jurisdiction of ASTM Committee C01 on Cementand is the direct responsibility of Subcommittee C01.30 on Time of Set.Current edition approved Dec.1,2013.Published January 2014.Originallyapproved in 1960.Last previous edition approved in 2008 as C451 08.DOI:10.1520/C0451-13.2Section on Safety,Manual of Cement Testing,Annual Book of ASTMStandards,Vol 04.01.3For 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.*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 When used for estimating the relative tendency of a cement tomanifest early stiffening,additional information of value maybe obtained if the remix procedure described in the ProcedureSection is employed.Under some conditions,a judgment maybe made by comparing the behavior in the initial test and in theremix procedure to differentiate a relatively less serious andless persistent tendency to early stiffening(false set)from onethat is more persistent and,consequently,mor