ASTM C61/C61M-00(2020)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C61/C61M −00 (Reapproved 2020)
Standard Specification for
Gypsum Keene’s Cement
This standard is issued under the fixed designation C61/C61M; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript 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. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This specification covers various grades of anhydrous
C11 Terminology Relating to Gypsum and Related Building
calcined gypsum known as gypsum Keene’s cement, designed
Materials and Systems
for use in the base and finish coats of gypsum plaster.
C471M Test Methods for ChemicalAnalysis of Gypsum and
NOTE 1—The setting time is accelerated by the addition of other
Gypsum Products (Metric)
materials.
C472 Test Methods for Physical Testing of Gypsum, Gyp-
NOTE 2—Keene’s cements are generally available as quick-setting and
sum Plasters, and Gypsum Concrete
standard-setting types. However, various grades of gypsum Keene’s
E11 Specification for Woven Wire Test Sieve Cloth and Test
cement of different fineness and setting time are available. Grades
Sieves
intended for use in scagliola castings and other special purposes should
conform to the requirements of this specification in all respects except
3. Terminology
fineness and setting time.
3.1 Definitions:
1.2 The values stated in either inch-pound or SI (metric)
3.1.1 Definitions of terms used in this specification shall be
units are to be regarded separately as standard. Within the text,
as defined in Terminology C11.
the SI units are shown in brackets. The values stated in each
3.2 Definitions of Terms Specific to This Standard:
system shall be used independently of the other. Values from
3.2.1 scagliola, n—an imitation marble used for ornamental
the two systems shall not be combined.
interior work.
1.3 The text of this standard references notes and footnotes
4. Chemical Composition
that provide explanatory material. These notes and footnotes
shall not be considered as requirements of the standard.
4.1 Combined Water—The cement shall show a combined
water content not more than 2 % when tested in accordance
1.4 The following safety hazards caveat pertains only to the
with Test Methods C471M.
test method in the appendix of this specification: This standard
does not purport to address all of the safety concerns, if any,
5. Physical Properties
associated with its use. It is the responsibility of the user of this
5.1 Testing shall be in accordance with Test Methods C472,
standard to establish appropriate safety, health, and environ-
except that in the determination of the setting time and
mental practices and determine the applicability of regulatory
compressive strength, the consistency used shall be such that a
limitations prior to use.
35-g conical plunger, described in Test Methods C472, shall
1.5 This international standard was developed in accor-
give a penetration of 30 6 2 mm, 20 s after release, the
dance with internationally recognized principles on standard-
measurement being made 5 min after the addition of the
ization established in the Decision on Principles for the
gypsum Keene’s cement to the gauging water.
Development of International Standards, Guides and Recom-
5.1.1 Setting Time— The cement shall set in not less than
mendations issued by the World Trade Organization Technical
20 min and not more than 6 h when determined by the Vicat
Barriers to Trade (TBT) Committee.
method.
5.1.2 Compressive Strength—GypsumKeene’scementshall
have a compressive strength of not less than 2500 psi
This specification is under the jurisdiction of ASTM Committee C11 on
Gypsum and Related Building Materials and Systems and is the direct responsibility
of Subcommittee C11.01 on Specifications and Test Methods for Gypsum Products. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved June 1, 2020. Published June 2020. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1926. Last previous edition approved in 2015 as C61/ Standards volume information, refer to the standard’s Document Summary page on
C61M – 00 (2015). DOI: 10.1520/C0061_C0061M-00R20. the ASTM website.
*A Summary of Changes section appears at the end of this standard
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C61/C61M − 00 (2020)
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