1、Designation: C61/C61M 00 (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 num
2、ber 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 anhydrou
3、scalcined gypsum known as gypsum Keenes cement, designedfor use in the base and finish coats of gypsum plaster.NOTE 1The setting time is accelerated by the addition of othermaterials.NOTE 2Keenes cements are generally available as quick-setting andstandard-setting types. However, various grades of g
4、ypsum 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 (m
5、etric)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 provi
6、de explanatory material. These notes and footnotesshall not be considered as requirements of the standard.1.4 The 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, associa
7、ted 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 BuildingMateria
8、ls 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 t
9、his 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
10、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 pe
11、netration 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 Keen
12、es 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
13、 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 Gypsu
14、m 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
15、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 Internatio
16、nal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. 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 sample
17、s 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 and the pur-chaser as p
18、art of the purchase agreement.8. Rejection8.1 Rejection of gypsum Keenes cement that fails toconform to the requirements of this specification shall bereported to the producer or supplier promptly and in writing.The written notice of rejection shall contain a statementdocumenting how the gypsum Keen
19、es cement has failed toconform to the requirements of this specification.9. Certification9.1 When specified in the purchase agreement, a producersor suppliers report shall be furnished at the time of shipmentcertifying that the product is in compliance with this specifi-cation.10. Packaging and Mark
20、ing10.1 Gypsum Keenes cement shall be dry, free of lumps,and shipped in packages.10.2 When shipped for resale, the following informationshall be legibly marked on each package or on a tag of suitablesize attached thereto:10.2.1 Name of producer or supplier,10.2.2 Brand,10.2.3 Description, and10.2.4
21、Net weight of package. Gross weight shall be shownwhere required.11. Keywords11.1 anhydrous gypsum; gypsum; gypsum Keenes cement;gypsum plaster; Keenes cement; plasterAPPENDIX(Nonmandatory Information)X1. FIELD TEST FOR GYPSUM KEENES CEMENTX1.1 ScopeX1.1.1 This method is a simple field test for the
22、identifica-tion of gypsum Keenes cement. It does not indicate the qualityof the cement, which shall be determined by the laboratorytests in the body of this specification.X1.2 Significance and UseX1.2.1 This method is of value to users in determiningwhether the material at hand is gypsum Keenes ceme
23、nt orsome other material.X1.3 ProcedureX1.3.1 Take a cupful of the material, mix with water to theconsistency of a thick paste, and transfer to a plate or piece ofglass. Let stand until fairly firm and definite signs of set havingbegun are manifest. This will be some time less than 2 h,depending on
24、climatic conditions.X1.3.2 Divide the sample, allowing one half to remainundisturbed. Take the other half, add a little water, remix, andthen allow it to “set up” again on the plate or glass.X1.4 Interpretation of ResultsX1.4.1 If the material is gypsum Keenes cement, theremixed portion will, within
25、 a few hours, become as hard andstrong as the portion that was not remixed.X1.5 Precision and BiasX1.5.1 It is not possible to state either the precision or biasof this test method because the method only determineswhether a material is or is not gypsum Keenes cement andthere are no numerical result
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30、cting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 00 (2015)3
