ASTM C28/C28M-00e1

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Designation: C 28/C 28M – 00
Standard Specification for
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Gypsum Plasters
This standard is issued under the fixed designation C 28/C 28M; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
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e NOTE—Note 1 was editorially added May 2002.
1. Scope C 472 Test Methods for Physical Testing of Gypsum, Gyp-
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sum Plasters, and Gypsum Concrete
1.1 This specification covers four gypsum plasters; gypsum
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C 778 Specification for Standard Sand
mill-mixed plaster, gypsum neat plaster, gypsum wood fibered
C 842 Specification for Application of Interior Gypsum
plaster and gypsum gauging plaster.
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Plaster
NOTE 1—Specification C 842 contains application procedures for inte-
E11 Specification for Wire-Cloth and Sieves for Testing
rior gypsum plaster.
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Purposes
1.2 The values stated in either inch-pound or SI (metric)
3. Terminology
units are to be regarded separately as the standard. Within the
text, the SI units are shown in brackets. The values stated in
3.1 Definitions—Definitions shall be in accordance with
each system shall be used independently of the other. Values
TerminologyC11.
from the two systems shall not be combined. This paragraph
3.2 Definitions of Terms Specific to This Standard:
does not apply to the appendix.
3.2.1 gypsum gauging plaster for finish coat, n—a calcined
1.3 The text of this standard references notes and footnotes
gypsum plaster designed to be mixed with lime putty for the
which provide explanatory material. These notes and footnotes
finish coat.
(excluding those in tables and figures) shall not be considered
3.2.2 gypsum neat plaster, n—calcined gypsum mixed at
as requirements of the standard.
the mill with other ingredients to control working quality and
1.4 The following safety hazards caveat pertains only to the
setting time.
test methods described in the appendix to this specification.
3.2.2.1 Discussion—Neat plaster is either fibered or unfi-
This standard does not purport to address all of the safety
bered. The addition of aggregate is required on the job.
concerns, if any, associated with its use. It is the responsibility
3.2.3 gypsum mill-mixed plaster, n—calcined gypsum plas-
of the user of this standard to establish appropriate safety and
ter, mixed at the mill with a mineral aggregate, designed to
health practices and determine the applicability of regulatory
function as a base coat to receive various finish coats.
limitations prior to use.
3.2.3.1 Discussion—Othermaterialsarenotprohibitedfrom
being added to control setting time and other desirable working
2. Referenced Documents
properties.
2.1 ASTM Standards:
3.2.4 gypsum wood-fibered plaster, n—A calcined gypsum
C11 Terminology Relating to Gypsum and Related Build-
plaster in which wood fiber is used as an aggregate.
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ing Materials and Systems
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4. Materials
C22 Specification for Gypsum
C35 Specification for Inorganic Aggregates for Use in
4.1 Calcined Gypsum—Calcined gypsum shall be manufac-
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Gypsum Plaster
tured from gypsum meeting the requirements of Specification
C 471M Test Methods for Chemical Analysis of Gypsum
C22.
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and Gypsum Products
4.2 Vermiculite Aggregate, SpecificationC35.
4.3 Perlite Aggregate, SpecificationC35.
4.4 Sand Aggregate, SpecificationC35.
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This specification is under the jurisdiction of ASTM Committee C11 on
4.5 Ottawa Sand, Specification C 778 for 20–30 sand.
Gypsum and Related Building Materials and Systems and is the direct responsibility
4.6 Wood Fiber, non staining wood fiber.
of Subcommittee C11.01 on Specifications and Test Methods for Gypsum Products.
Current edition approved May 10, 2000. Published July 2000. Originally
{1
published as C 28 – 20 T. Last previous edition C 28 – 96 .
2 3
Annual Book of ASTM Standards, Vol 04.01. Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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C 28/C 28M – 00
TABLE 1 Composition and Physical Properties
B
Composition, Aggregate per 100 lb Compressive Strength
A
Setting Time
of Plaster, not more than not less than
Product Aggregate Type
3 3
ft m hours psi MPa
1
Mill-Mixed Plaster over Lath Base Vermiculite 2 0.057 1 ⁄2 to 8 450 3.1
1
Perlite 2 0.057 1 ⁄2 to 8 600 4.1
1
Sand 2.5 0.071 1 ⁄2 to 8 700 4.8
1
Mill-Mixed Plaster over Masonry Vermiculite 3 0.085 1 ⁄2 to 8 325 2.2
1
Perlite 3 0.085 1 ⁄2 to 8 400 2.8
1
Sand 3 0.085 1 ⁄2 to 8 400 2.8
C D
Neat Plaster none . . 2 to 16 750 5.2
1
Wood Fibered Plaster none . . 1 ⁄2 to
...