ASTM C22/C22M-00(2021)

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: C22/C22M −00 (Reapproved 2021)
Standard Specification for
Gypsum
This standard is issued under the fixed designation C22/C22M; 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.
1. Scope 4. Chemical Composition
1.1 This specification covers gypsum, calcium sulfate com- 4.1 Gypsum shall contain not less than 70.0 weight percent
bined with two molecules of water in crystalline form and CaSO ·2H O.
4 2
having the approximate chemical formula CaSO ·2H O.
4 2
4.2 The chemical composition, within the limits prescribed
1.2 The values stated in either inch-pound units or SI by 4.1, shall be specified in the purchase order or contract.
(metric) are to be regarded separately as the standard. Within
5. Physical Properties
the text, the SI units are shown in brackets. The values stated
5.1 Size—If necessary, gypsum shall be crushed or ground,
in each system shall be used independently of the other. Values
or both, to the size specified in the purchase order.
from the two systems shall not be combined.
1.3 The text of this specification references notes and
6. Sampling
footnotes which provide explanatory material. These notes and
6.1 Bulk—When gypsum is shipped in bulk, samples of
footnotes (excluding those in tables and figures) shall not be
approximately 5 lb [2 kg] each shall be taken at regular
considered as requirements of the specification.
intervals during the complete loading or unloading of the
1.4 This international standard was developed in accor-
carrier, in such a way as to accumulate not less than 200 lb
dance with internationally recognized principles on standard-
[90 kg] of material and to represent correctly the percentages
ization established in the Decision on Principles for the
of both the coarse particles and the fines in the shipment. This
Development of International Standards, Guides and Recom-
material shall be broken to pass a 1-in. [25.0 mm] sieve,
mendations issued by the World Trade Organization Technical
thoroughly mixed, and reduced by quartering to provide not
Barriers to Trade (TBT) Committee.
less than a 1-lb [0.5 kg] sample for the laboratory.
6.2 Packages—When gypsum is shipped in packages, not
2. Referenced Documents
less than 1 % of the packages shall be sampled. Samples shall
2.1 ASTM Standards:
be taken from both the surface and the center of the packages.
C11 Terminology Relating to Gypsum and Related Building
These samples shall then be broken, mixed, and quartered in
Materials and Systems
accordance with 6.1.
C471M Test Methods for ChemicalAnalysis of Gypsum and
6.3 Laboratory Samples—Each laboratory sample shall be
Gypsum Products (Metric)z
placed immediately in an airtight container and shipped to the
C472 Test Methods for Physical Testing of Gypsum, Gyp-
laboratory for testing.
sum Plasters, and Gypsum Concrete
7. Test Methods
3. Terminology
7.1 The chemical composition of gypsum shall be deter-
3.1 Definitions:
mined in accordance with Test Methods C471M.
3.1.1 Definitions shall be in accordance with Terminology
7.2 The physical properties of gypsum shall be determined
C11.
in accordance with Test Methods C472.
1 8. Inspe
...