ASTM_C_61_-_C_61M_-_00_2015.pdf

Designation:C61/C61M00(Reapproved 2015)Standard Specification forGypsum Keenes Cement1This standard is issued under the fixed designation C61/C61M;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This specification covers various grades of anhydrouscalcined gypsum known as gypsum Keenes cement,designedfor use in the base and finish coats of gypsum plaster.NOTE1The setting time is accelerated by the addition of othermaterials.NOTE2Keenes cements are generally available as quick-setting andstandard-setting types.However,various grades of gypsum Keenescement of different fineness and setting time are available.Gradesintended for use in scagliola castings and other special purposes shouldconform to the requirements of this specification in all respects exceptfineness and setting time.1.2 The values stated in either inch-pound or SI(metric)units are to be regarded separately as standard.Within the text,the SI units are shown in brackets.The values stated in eachsystem shall be used independently of the other.Values fromthe two systems shall not be combined.1.3 The text of this standard references notes and footnotesthat provide explanatory material.These notes and footnotesshall not be considered as requirements of the standard.1.4The following safety hazards caveat pertains only tothe test method in the appendix of this specification:Thisstandard does not purport to address all of the safety concerns,if any,associated with its use.It is the responsibility of the userof this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2.Referenced Documents2.1 ASTM Standards:2C11 Terminology Relating to Gypsum and Related BuildingMaterials and SystemsC471M Test Methods for ChemicalAnalysis of Gypsum andGypsum Products(Metric)C472 Test Methods for Physical Testing of Gypsum,Gyp-sum Plasters and Gypsum ConcreteE11 Specification for Woven Wire Test Sieve Cloth and TestSieves3.Terminology3.1 DefinitionsDefinitions of terms used in this specifica-tion shall be as defined in Terminology C11.3.2 Definitions of Terms Specific to This Standard:3.2.1 scagliola,nan imitation marble used for ornamentalinterior work.4.Chemical Composition4.1 Combined WaterThe cement shall show a combinedwater content not more than 2%when tested in accordancewith Test Methods C471M.5.Physical Properties5.1 Testing shall be in accordance with Test Methods C472,except that in the determination of the setting time andcompressive strength,the consistency used shall be such that a35g conical plunger,described in Test Methods C472,shallgive a penetration of 30 6 2 mm,20 s after release,themeasurement being made 5 min after the addition of thegypsum Keenes cement to the gauging water.5.1.1 Setting Time The cement shall set in not less than 20min and not more than 6 h when determined by the Vicatmethod.5.1.2 Compressive StrengthGypsum Keenes cement shallhave a compressive strength of not less than 2500 psi 17MPa.Soak standard Keenes cement in water for 20 min withoccasional stirring before filling the mold in the compressivestrength determination.5.1.3 FinenessThe cement shall all pass a No.14 1.40mm sieve;not less than 98%shall pass a No.40 425msieve,and not less than 80%shall pass a No.100 150msieve.31This specification is under the jurisdiction of ASTM Committee C11 onGypsum and Related Building Materials and Systems and is the direct responsibilityof Subcommittee C11.01 on Specifications and Test Methods for Gypsum Products.Current edition approved Oct.1,2015.Published October 2015.Originallyapproved in 1926.Last previous edition approved in 2011 as C61/C61M 00(2011).DOI:10.1520/C0061_C0061M-00R15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Detailed requirements for these sieves are given in ASTM Specification E11.*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 6.Sampling6.1 Randomly select not less than 1%of the packages,butnot less than 5 packages.Take samples of approximately equalamounts from both the outer portion and the center of eachpackage.Mix the samples so obtained to provide a compositesample of not less than 15 lb 6.8 kg.Immediately place thesample in a clean,dry,airtight container for delivery to thelaboratory.7.Inspection7.1 Inspection of the gypsum Keenes cement shall beagreed upon between the producer or supplier