ASTM C28/C28M-10(2015)

Standard Specification for Gypsum Plasters

ABSTRACT
This specification covers four gypsum plasters; gypsum mill-mixed plaster, gypsum neat plaster, gypsum wood fibered plaster, and gypsum gauging plaster. The plasters shall contain a volume of aggregate not more than requirements prescribed. Compressive strength test and Vicat test shall be performed to meet the requirements.
SCOPE
1.1 This specification covers gypsum mill-mixed plaster, gypsum neat plaster, gypsum wood-fibered plaster, and gypsum gauging plaster.
Note 1: Specification C842 contains application procedures for interior gypsum plaster.  
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. This paragraph does not apply to the appendix.  
1.3 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Sep-2015
• ICS: 91.100.10 - Cement. Gypsum. Lime. Mortar
• Technical Committee: C11 - Gypsum and Related Building Materials and Systems
• Drafting Committee: C11.01 - Specifications and Test Methods for Gypsum Products

Relations

• Replaces: ASTM C28/C28M-10 - Standard Specification for Gypsum Plasters
• Effective Date: 01-Oct-2015
• Replaced By: ASTM C28/C28M-10(2020) - Standard Specification for Gypsum Plasters
• Effective Date: 01-Jun-2020
• Referred By: ASTM C11-23 - Standard Terminology Relating to Gypsum and Related Building Materials and Systems
• Effective Date: 01-Oct-2015
• Referred By: ASTM C471M-20ae1 - Standard Test Methods for Chemical Analysis of Gypsum and Gypsum Products (Metric)
• Effective Date: 01-Oct-2015
• Referred By: ASTM C631-09(2020) - Standard Specification for Bonding Compounds for Interior Gypsum Plastering
• Effective Date: 01-Oct-2015
• Referred By: ASTM C317/C317M-00(2019) - Standard Specification for Gypsum Concrete
• Effective Date: 01-Oct-2015
• Referred By: ASTM C110-20 - Standard Test Methods for Physical Testing of Quicklime, Hydrated Lime, and Limestone
• Effective Date: 01-Oct-2015
• Referred By: ASTM C842-05(2021) - Standard Specification for Application of Interior Gypsum Plaster
• Effective Date: 01-Oct-2015

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:C28/C28M −10 (Reapproved 2015)
Standard Specification for
Gypsum Plasters
This standard is issued under the fixed designation C28/C28M; 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 C11 Terminology Relating to Gypsum and Related Building
Materials and Systems
1.1 This specification covers gypsum mill-mixed plaster,
C22/C22M Specification for Gypsum
gypsum neat plaster, gypsum wood-fibered plaster, and gyp-
C35 Specification for Inorganic Aggregates for Use in Gyp-
sum gauging plaster.
sum Plaster
NOTE 1—Specification C842 contains application procedures for inte-
C471M Test Methods for ChemicalAnalysis of Gypsum and
rior gypsum plaster.
Gypsum Products (Metric)
1.2 The values stated in either SI units or inch-pound units
C472 Test Methods for Physical Testing of Gypsum, Gyp-
are to be regarded separately as standard. Within the text, the
sum Plasters and Gypsum Concrete
SI units are shown in brackets. The values stated in each
C778 Specification for Standard Sand
system may not be exact equivalents; therefore, each system
C842 Specification forApplication of Interior Gypsum Plas-
shall be used independently of the other. Combining values
ter
from the two systems may result in non-conformance with the
E11 Specification for Woven Wire Test Sieve Cloth and Test
standard. This paragraph does not apply to the appendix.
Sieves
1.3 The text of this standard references notes and footnotes
3. Terminology
which provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered
3.1 Definitions—Definitions shall be in accordance with
as requirements of the standard.
Terminology C11.
3.2 Definitions of Terms Specific to This Standard:
1.4 This standard does not purport to address all of the
3.2.1 gypsum gauging plaster for finish coat, n—a calcined
safety concerns, if any, associated with its use. It is the
gypsum plaster designed to be mixed with lime putty for the
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- finish coat.
bility of regulatory limitations prior to use.
3.2.2 gypsum neat plaster, n—calcined gypsum mixed at the
1.5 This international standard was developed in accor-
mill with other ingredients to control working quality and
dance with internationally recognized principles on standard-
setting time.
ization established in the Decision on Principles for the
3.2.2.1 Discussion—Neat plaster is either fibered or unfi-
Development of International Standards, Guides and Recom-
bered. The addition of aggregate is required on the job.
mendations issued by the World Trade Organization Technical
3.2.3 gypsum mill-mixed plaster, n—calcined gypsum
Barriers to Trade (TBT) Committee.
plaster, mixed at the mill with a mineral aggregate, designed to
function as a base coat to receive various finish coats.
2. Referenced Documents
3.2.3.1 Discussion—Other materials are not prohibited from
2.1 ASTM Standards:
beingaddedtocontrolsettingtimeandotherdesirableworking
properties.
3.2.4 gypsum wood-fibered plaster, n—a calcined gypsum
This specification is under the jurisdiction of ASTM Committee C11 on
plaster in which wood fiber is used as an aggregate.
Gypsum and Related Building Materials and Systems and is the direct responsibility
of Subcommittee C11.01 on Specifications and Test Methods for Gypsum Products.
Current edition approved Oct. 1, 2015. Published October 2015. Originally 4. Materials
approved in 1920. Last previous edition approved in 2010 as C28/C28M – 10. DOI:
4.1 Calcined Gypsum—Calcined gypsum shall be manufac-
10.1520/C0028_C0028M-10R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or tured from gypsum meeting the requirements of Specification
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
C22/C22M.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 4.2 Vermiculite Aggregate, Specification C35.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C28/C28M−10 (2015)
4.3 Perlite Aggregate, Specification C35. 7. Sampling
4.4 Sand Aggregate, Specification C35.
7.1 At least 1 % of the packages, but not less than 5
packages, shall be sampled. Packages to be sampled shall be
4.5 Ottawa Sand, Specification C778 for 20–30 sand.
selected at random. Samples shall be taken both from the outer
4.6 Wood Fiber, non staining wood fiber.
portion and the center of each package. The materials so
obtained shall be thoroughly mixed to provide a composite
5. Composition
sample of not less than 7 lb [3.2 kg]. This composite sample
5.1 When tested in accordance with Test Methods C471M,
shall be placed immediately in a clean, dry, airtight container
calcined gypsum shall contain no less than 66.0 weight % for delivery to the laboratory.
CaSO · ⁄2 H O.
4 2
8. Packaging and Package Marking
5.2 Aggregate—plasters shall contain a volume of aggregate
not more than that shown in Table 1.
8.1 Gypsum plasters shall be dry and free of lumps, and
shall be shipped in packages.
NOTE 2—An approximation of the aggregate content may be made by
using the test methods in the appendix. A more accurate method for
8.2 When shipped for resale, the following information
determining sand in plaster is described in Test Methods C471M. Test
shall be legibly marked on each package or on a tag of suitable
MethodsC471Mrequiresthattheoriginalsandandplastercomponentsbe
size attached to the package:
available separately.
8.2.1 Name of manufacturer or seller,
6. Mechanical Properties
8.2.2 Brand name, if any, and
8.2.3 Net weight of the package.
6.1 Compressive Strength—When tested in accordance with
Test Methods C472 the compressive strength shall be as
specified in Table 1. 9. Inspection
6.2 Setting Time—When tested in accordance with Test 9.1 Inspection of the gypsum plaster shall be agreed upon
MethodsC472usingtheVicatmethod,thesettingtimeshallbe
between the purchaser and the supplier as part of the purchase
as specified in Table 1. agreement.
NOTE 3—Setting Time—Attention is directed to conditions affecting job
10. Rejection
set of gypsum plasters that are usually beyond the control of the producer.
Materials added at the site of application such as water and aggregates
10.1 Rejection of gypsum plaster that fails to conform to the
affect job sets. In addition, the various bases with different absorptive
requirements of this specification shall be reported to the
values may affect job performance.The plaster may be retarded to provide
producer or supplier promptly and in writing. The notice of
a setting time of not more than 4 h. Setting times more than 2 h may result
in lower compressive strengths.
rejection shall contain a statement documenting requirements
of this specification.
6.3 Fineness of Gauging Plaster for Finish Coat—When
tested in accordance with Test Method C472 100 % shall pass
11. Certification
aNo.14[1.4mm]sieveandnotlessthan60 %shallpassaNo.
100 [150 µm] sieve.
11.1 When specified in the purchase agreement, a manufac-
turer’s or supplier’s report shall be furnished at the time of
shipment certifying that the product is in compliance with this
specification.
Detailed requirements for these sieves are given in Specification E11.
TABLE 1 Composition and Physical Properties
B
Composition, Aggregate per 100 lb
A Compressive Strength
Setting Time
of Plaster, not more than not less than
Product Aggregate Type
3 3
ft m hours psi MPa
Mill-Mixed Plaster over Lath Base Vermiculite 2 0.057 1 ⁄2 to 8 450 3.1
Perlite 2 0.057 1 ⁄2 to 8 600 4.1
Sand 2.5 0.071 1 ⁄2 to 8 700 4.8
Mill-Mixed Plaster over Masonry Vermiculite 3 0.085 1 ⁄2 to 8 325 2.2
Perlite 3 0.085 1 ⁄2 to 8 400 2.8
Sand 3 0.085 1 ⁄2 to 8 400 2.8
C D
Neat Plaster none . . 2 to 16 750 5.2
Wood Fibered Plaster none . . 1 ⁄2 to 8 1200 8.3
E
Gauging Plaster none . . 1200 8.3
A
Setting time shall be not less than the shorter time shown nor more than the longer
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C28/C28M − 10 C28/C28M − 10 (Reapproved 2015)
Standard Specification for
Gypsum Plasters
This standard is issued under the fixed designation C28/C28M; 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
1.1 This specification covers gypsum mill-mixed plaster, gypsum neat plaster, gypsum wood-fibered plaster, and gypsum
gauging plaster.
NOTE 1—Specification C842 contains application procedures for interior gypsum plaster.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the SI units
are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used
independently of the other. Combining values from the two systems may result in non-conformance with the standard. This
paragraph does not apply to the appendix.
1.3 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered as requirements of the standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
C11 Terminology Relating to Gypsum and Related Building Materials and Systems
C22/C22M Specification for Gypsum
C35 Specification for Inorganic Aggregates for Use in Gypsum Plaster
C471M Test Methods for Chemical Analysis of Gypsum and Gypsum Products (Metric)
C472 Test Methods for Physical Testing of Gypsum, Gypsum Plasters and Gypsum Concrete
C778 Specification for Sand
C842 Specification for Application of Interior Gypsum Plaster
E11 Specification for Woven Wire Test Sieve Cloth and Test Sieves
3. Terminology
3.1 Definitions—Definitions shall be in accordance with Terminology C11.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 gypsum gauging plaster for finish coat, n—a calcined gypsum plaster designed to be mixed with lime putty for the finish
coat.
3.2.2 gypsum neat plaster, n—calcined gypsum mixed at the mill with other ingredients to control working quality and setting
time.
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.
Current edition approved Oct. 1, 2010. Published November 2010October 2015. Originally approved in 1920. Last previous edition approved in 20052010 as
C28/C28M–00(2005).C28/C28M – 10. DOI: 10.1520/C0028_C0028M-10.10.1520/C0028_C0028M-10R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3.2.2.1 Discussion—
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C28/C28M − 10 (2015)
Neat plaster is either fibered or unfibered. The addition of aggregate is required on the job.
3.2.3 gypsum mill-mixed plaster, n—calcined gypsum plaster, mixed at the mill with a mineral aggregate, designed to function
as a base coat to receive various finish coats.
3.2.3.1 Discussion—
Other materials are not prohibited from being added to control setting time and other desirable working properties.
3.2.4 gypsum wood-fibered plaster, n—a calcined gypsum plaster in which wood fiber is used as an aggregate.
4. Materials
4.1 Calcined Gypsum—Calcined gypsum shall be manufactured from gypsum meeting the requirements of Specification
C22/C22M.
4.2 Vermiculite Aggregate, Specification C35.
4.3 Perlite Aggregate, Specification C35.
4.4 Sand Aggregate, Specification C35.
4.5 Ottawa Sand, Specification C778 for 20–30 sand.
4.6 Wood Fiber, non staining wood fiber.
5. Composition
5.1 When tested in accordance with Test Methods C471M, calcined gypsum shall contain no less than 66.0 weight % CaSO · ⁄2
H O.
5.2 Aggregate—plasters shall contain a volume of aggregate not more than that shown in Table 1.
NOTE 2—An approximation of the aggregate content may be made by using the test methods in the appendix. A more accurate method for determining
sand in plaster is described in Test Methods C471M. Test Methods C471M requires that the original sand and plaster components be available separately.
6. Mechanical Properties
6.1 Compressive Strength—When tested in accordance with Test Methods C472 the compressive strength shall be as specified
in Table 1.
6.2 Setting Time—When tested in accordance with Test Methods C472 using the Vicat method, the setting time shall be as
specified in Table 1.
NOTE 3—Setting Time—Attention is directed to conditions affecting job set of gypsum plasters that are usually beyond the control of the producer.
Materials added at the site of application such as water and aggregates affect job sets. In addition, the various bases with different absorptive values may
affect job performance. The plaster may be retarded to provide a setting time of not more than 4 h. Setting times more than 2 h may result in lower
compressive strengths.
6.3 Fineness of Gauging Plaster for Finish Coat—When tested in accordance with Test Method C472 100 % shall pass a No.
14 [1.4 mm] sieve and not less than 60 % shall pass a No. 100 [150 μm] sieve.
Detailed requirements for these sieves are given in Specification E11.
TABLE 1 Composition and Physical Properties
B
Composition, Aggregate per 100 lb
Compressive Strength
A
Setting Time
not less than
of Plaster, not more than
Product Aggregate Type
3 3
ft m hours psi MPa
Mill-Mixed Plaster over Lath Base Vermiculite 2 0.057 1 ⁄2 to 8 450 3.1
Perlite 2 0.057 1 ⁄2 to 8 600 4.1
Sand 2.5 0.071 1 ⁄2 to 8 700 4.8
Mill-Mixed Plaster over Masonry Vermiculite 3 0.085 1 ⁄2 to 8 325 2.2
Perlite 3 0.085 1 ⁄2 to 8 400 2.8
Sand 3 0.085 1 ⁄2 to 8 400 2.8
C D
Neat Plaster none . . 2 to 16 750 5.2
Wood Fibered Plaster none . . 1 ⁄2 to 8 1200 8.3
E
Gauging Plaster none . . 1200 8.3
A
Setting time shall be not less than the shorter time shown nor more than the longer time shown.
B
Compressive strengths are as tested at the setting times specified in Test Methods C472.
C
When mixed with 3 parts by weight of Ottawa sand.
D
When mixed with 2 parts by weight of Ottawa sand.
E
When not retarded, the setting time shall be not less than 20 nor more than 40 minutes and, when retarded, not less than 40 minutes.
C28/C28M − 10 (2015)
7. Sampling
7.1 At least 1 % of the packages, but not less than 5 packages, shall be sampled. Packages to be sampled shall be selected at
random. Samples shall be taken both from the outer portion and the center of each package. The materials so obtained shall be
thoroughly mixed to provide a composite sample of not less than 7 lb [3.2 kg]. This composite sample shall be placed immediately
in a clean, dry, airtight container for delivery to the laboratory.
8. Packaging and Package Marking
8.1 Gypsum plasters shall be dry and free of lumps, and shall be shipped in packages.
8.2 When shipped for resale, the following information shall be legibly marked on each package or on a tag of suitable size
attached to the package:
8.2.1 Name of manufacturer or seller,
8.2.2 Brand name, if any, and
8.2.3 Net weight of the package.
9. Inspection
9.1 Inspection of the gypsum plaster shall be agreed upon between the purchaser and the supplier as part of the purchase
agreement.
10. Rejection
10.1 Rejection of gypsum plaster that fails to conform to the requirements of this specification shall be reported to the
...