ASTM C472-99(2009)
(Test Method)Standard Test Methods for Physical Testing of Gypsum, Gypsum Plasters and Gypsum Concrete
Standard Test Methods for Physical Testing of Gypsum, Gypsum Plasters and Gypsum Concrete
ABSTRACT
These test methods cover the physical testing of gypsum, gypsum plasters, and gypsum concrete. Test methods are detailed for the following: precautions for physical tests, reagents and materials, free water, fineness, normal consistency of gypsum plaster and gypsum concrete, setting time, setting time (temperature rise method), compressive strength, and density. Materials include distilled or deionized water and standard sand. For each test method, the following are specified: significance and use, apparatus, and procedure.
SCOPE
1.1 These test methods cover the physical testing of gypsum, gypsum plasters, and gypsum concrete.
1.2 The test methods appear in the following sections:
Sections Precautions for Physical Tests4 Reagents and Materials5 Free Water6 Fineness7 Normal Consistency of Gypsum Plaster8 Normal Consistency of Gypsum Concrete9 Setting Time10 Setting Time (Temperature Rise Method)11 Compressive Strength12 Density13
1.3 The values regarded as the standard are either in inch-pound units or SI (metric). The values stated first shall be regarded as the standard. Values following in parentheses are approximate and are provided for information purposes only.
1.4 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) are not requirements of the standard.
1.5 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. For a specific precautionary statement, see X1.2.1.
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Standards Content (Sample)
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Designation:C472 −99(Reapproved 2009)
Standard Test Methods for
Physical Testing of Gypsum, Gypsum Plasters and Gypsum
Concrete
This standard is issued under the fixed designation C472; 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 Department of Defense.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 These test methods cover the physical testing of
C11 Terminology Relating to Gypsum and Related Building
gypsum, gypsum plasters, and gypsum concrete.
Materials and Systems
1.2 The test methods appear in the following sections:
C778 Specification for Sand
E11 Specification for Woven Wire Test Sieve Cloth and Test
Sections
Sieves
Precautions for Physical Tests 4
Reagents and Materials 5
3. Terminology
Free Water 6
Fineness 7
3.1 Definitions:
Normal Consistency of Gypsum Plaster 8
3.1.1 For useful definitions refer to Terminology C11.
Normal Consistency of Gypsum Concrete 9
Setting Time 10
4. Precautions for Physical Tests
Setting Time (Temperature Rise Method) 11
Compressive Strength 12
4.1 Gypsum products are greatly affected by small amounts
Density 13
of impurities introduced by careless laboratory manipulation.
In order to obtain accurate results, it is absolutely essential to
1.3 The values regarded as the standard are either in
observe the following precautions:
inch-pound units or SI (metric). The values stated first shall be
4.1.1 Keep all apparatus thoroughly clean. Remove all
regarded as the standard. Values following in parentheses are
traces of set plaster.
approximate and are provided for information purposes only.
NOTE 1—For mixing pastes and mortars, a 500-ml rubber dental bowl
1.4 The text of this standard references notes and footnotes
is a convenience.
which provide explanatory material. These notes and footnotes
NOTE 2—Use care when drying gypsum, gypsum plasters, or gypsum
(excluding those in tables and figures) are not requirements of concrete. Exceeding the specified drying temperatures may calcine the
specimens, which will cause inaccurate test results.
the standard.
5. Reagents and Materials
1.5 This standard does not purport to address all of the
5.1 Distilled or Deionized Water—free of chlorides and
safety concerns, if any, associated with its use. It is the
sulfates at a temperature of 21 6 1°C (70 6 2°F).
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica- 5.2 Standard Sand— Specification C778, 20–30 sand.
bility of regulatory limitations prior to use. For a specific
6. Free Water
precautionary statement, see X1.2.1.
6.1 Significance and Use—This test method determines the
free water contained in gypsum, gypsum plasters, and gypsum
concrete samples, and prepares the sample for subsequent
These test methods are under the jurisdiction of ASTM Committee C11 on
testing.
Gypsum and Related Building Materials and Systems and are the direct responsi-
bility 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 Sept. 1, 2009. Published September 2009. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1961. Last previous edition approved in 2004 as C472–99(2004). DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C0472-99R09. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C472−99 (2009)
retained material temporarily to another vessel, invert the sieve over a
6.2 Apparatus:
sheet of paper on the table and tap it sharply against the table. Then
6.2.1 Balance, capable of weighing not less than 500 g at
transfer all the retained material back into the sieve and continue sieving.
a precision of 0.1 g.
7.4 Report—Report the percent by weight retained on each
6.2.2 Drying Oven, set at 45 6 3°C.
sieve or passing particular sieves in accordance with the
6.2.3 Desiccator, containing calcium chloride or equiva-
material specification to the nearest full percentage point.
lent desiccant.
7.5 Precision and Bias—The precision and bias of the
6.3 Procedure:
fineness test method have not been determined.
6.3.1 Weigh a sample of not less than 500 g of the material
as received to the nearest 0.1 g and spread it to a thin layer in
8. Normal Consistency of Gypsum Plaster
a suitable-vessel. Place in an oven (6.2.2) and dry for 2 h; then
cool in a desiccator (6.2.3) and weigh again. 8.1 Significance and Use—This test method is used to
determine the volume of water required for mixing gypsum
6.3.2 Retain the dried sample in an airtight container until
used for the fineness test (Section 7). plaster when performing the setting time and compressive
strength tests.
6.4 Report—Report the loss in weight as a percentage of the
original weight of the sample as received to a precision of 8.2 Apparatus:
0.1%. 8.2.1 Modified Vicat Apparatus—The modified Vicat appa-
ratus (Fig. 1) shall consist of a bracket, A, bearing a movable
6.5 Precision and Bias—The precision and bias of the free
brassrod,B,6.3mmindiameterandofsuitablelengthtofitthe
water test method have not been determined.
Vicat Bracket. A conical plunger made of aluminum with an
7. Fineness
apex angle of 53° 08 min and a height of 45 mm shall be
attachedtothelowerendoftherod.Thetotalweightoftherod
7.1 Significance and Use—This test method covers a proce-
dure for determining the fineness of gypsum and gypsum
plasters and is used to determine compliance with gypsum and
This method is described by Kuntze, R. A., “An Improved Method for the
gypsum plaster specifications. The degree of correlation be-
Normal Consistency of Gypsum Plasters,” ASTM Bulletin No. 246, ASTM, May
tween the results of this test method and service performance
1960, p. 35.
has not been determined.
7.2 Apparatus:
7.2.1 Sieves, as required by a particular gypsum or gypsum
plaster specification, in accordance with Specification E11.
7.2.2 Balance, capable of weighing not less than 1000 g at
a precision of 0.1 g.
7.2.3 Mechanical Sieving Machine
7.3 Procedure:
7.3.1 Determine fineness by sieving a known weight of the
dried sample through sieves of the specified sizes (Note 3 and
Note 4). The size of the sample to be used in determining
fineness depends upon the particle size of the material. If the
material will pass a 6.3-mm ( ⁄4-in.) sieve, a 100-g sample will
besufficient;ifthelargestparticlesaremorethan25mm(1in.)
in diameter, use not less than a 1000-g sample. With these
limitations the size of sample to be used is left to the discretion
of the operator. Shake the sample through each sieve with as
little abrasion as possible (Note 5). Weigh the amount of
material retained on each sieve and calculate the fineness,
expressed as a percentage of the weight of the original sample.
7.3.2 If a mechanical sieving machine is used, make a series
of tests at one minute intervals, with each type of material and
sieve size combination to be used. When not more than 0.5 g
passes each sieve in a one minute interval, use that time as the
standard sieving time for that test procedure on that machine.
NOTE 3—For suggested method of sieving gypsum through a 45-µm
(No. 325) sieve, see Appendix X1.
NOTE 4—The sizes of the sieves to be used are given in the specifica-
A—Hinged support bracket D—Graduation mark
tions of ASTM covering the particular product in question.
B—Plunger support rod E—Lock screw
NOTE 5—When sieving by hand through a 150-µm (No. 100) sieve, use
C—Conical plunger F—Modified scale
a lateral motion, and tap the side of the sieve with the palm of the hand.
G—Weight
Continuewithoutbrushinguntilnotmorethan0.5gpassesthroughduring
1 min of sieving. If the sieve openings become clogged, transfer the FIG. 1 Modified Vicat Apparatus (Conical Plunger Method)
C472−99 (2009)
andplungershallbe35g.Ameansshallbeprovidedforadding 9.2 Apparatus:
a weight, G, to the rod, increasing the total weight to 50 g. The 9.2.1 Consistometer (Fig. 2)—The consistometer consists of
rod shall be capable of being held in any position by a screw, a conical vessel made of noncorroding, nonabsorbent material,
E. The rod shall have a mark, D, midway between the ends and having an inside diameter of 9 in. (229 mm) at the top and
3 1
which moves under a scale, F, graduated in millimetres, 1 ⁄4 in. (44.5 mm) at the bottom, and a height of 5 ⁄2 in. (139.7
attached to the bracket, A. mm). It shall be provided with a sliding gate at the bottom and
8.2.2 Mold—The conical ring mold shall be made of a supported so that the bottom is 4 in. (102 mm) above the base
noncorroding, nonabsorbent material, and shall have an inside plate. The base plate shall be of plate glass, free of scratches
diameter of 60 mm at the base and 70 mm at the top and a and about 18 in. (457 mm) square.
height of 40 mm. 9.2.2 Balance, capable of weighing not less than 2000 g at
8.2.3 Base Plate—The base plate for supporting the ring a precision of 1 g.
mold shall be of plate glass and about 100 mm square.
9.3 Procedure:
8.2.4 Balance, capable of weighing not less than 500 g at a
9.3.1 Cleananddrytheconsistometerandthebaseplateand
precision of 0.1 g.
close the sliding gate.
8.2.5 Graduated Cylinder, shall be made to deliver the
9.3.2 Sift 2000 g of the sample into a known volume of
indicated volume at 20°C (68°F) and shall be subdivided to not
water (see 5.1) to which 1.0 g of sodium citrate has previously
less than 1 mL.
been added. After allowing the sample to soak for 1 min, stir
8.3 Procedure: the mixture for 3 min to an even fluidity. Pour the mixture into
8.3.1 Clean the plunger, mold, and base plate of the modi- the consistometer until level with the top. Then rapidly and
fied Vicat apparatus. Apply a thin coat of petroleum jelly or completely open the sliding gate, allowing the mixture to run
other suitable lubricant to the upper surface of the base plate in out onto the base plate. When the sliding gate is opened, take
order to prevent leaks during the test. care to avoid jarring the consistometer.
8.3.2 Sift a weighed quantity of the sample (200 to 300 g as 9.3.3 Measure the resulting patty along its major and minor
required to fill the mold) into a known volume of water (See axes and determine the average diameter.
5.1). If the plaster is unretarded, add to the mixing water 0.2 g 9.3.4 Test gypsum concrete with different amounts of water
of sodium citrate per 100 g of sample. After allowing the until a patty diameter of 380 6 13 mm (15 6 ⁄2 in.) is
sample to soak for 2 min, stir the mixture for 1 min to an even obtained.
fluidity. Pour this sample into the ring mold, work slightly to
9.4 Report—Report the normal consistency as the number
remove air bubbles, and then strike off flush with the top of the
of millilitres of water to the nearest whole millilitre required to
mold. Wet the plunger of the modified Vicat apparatus and
be added to 100 g of the gypsum concrete.
lowerittothesurfaceofthesampleatapproximatelythecenter
9.5 Precision and Bias—The precision and bias of the test
of the mold. Read the scale and release the plunger immedi-
method for normal consistency of gypsum concrete have not
ately.After the rod has settled, read the scale again. Make three
been determined.
determinations on each mix, care being taken to have the mold
completely filled and the plunger clean and wet.
10. Setting Time
8.3.3 Test gypsum molding plaster and gypsum gauging
plasterwithdifferentamountsofwateruntilapenetrationof30
10.1 Significance and Use—This test method is used to
6 2 mm is obtained. Use the rod and plunger for this
determine the setting time of gypsum plaster and gypsum
determination weighing 35 g.
concrete, and is used to determine compliance with gypsum
8.3.4 Test all gypsum mixtures containing aggregates with
plaster and gypsum concrete specifications. Since variable job
different amounts of water until a penetration of 20 62mmis
conditions influence the setting time, the degree of correlation
obtained. Add weight to the rod and plunger to bring the total
between this test method and service performance has not been
weight to 50 g for these determinations.
determined.
8.3.5 Mix gypsum neat plaster with standard sand (see 5.2)
10.1.1 This test method does not determine the time of
in the ratio of 200 g of sand to 100 g of plaster before testing
complete hydration of gypsum plaster or gypsum concrete. To
for normal consistency.
determine the time of complete hydration see Setting Time,
(Temperature Rise Method,) Section 11.
8.4 Report: Report the normal consistency as the average
number of millilitres of water required to be added to 100 g of
10.2 Apparatus:
the dry mixture to the nearest whole millilitre.
10.2.1 Vicat Apparatus—The Vicat apparatus (Fig. 3) shall
consist of a frame, A, bearing a movable rod, B, weighing 300
8.5 Precision and Bias—The precision and bias of the test
g, one end, C, the plunger end, being 10 mm in diameter for a
method for normal consistency of gypsum plaster have not
distance of not less than 50 mm, the other end having a
been determined.
removable needle, D, 1 mm in diameter and 50 mm in length.
9. Normal Consistency of Gypsum Concrete
The rod, B, shall be reversible, shall be able to be held in any
9.1 Significance and Use—This test method is used to position by a screw, E, and shall have an adjustable indicator,
determine the volume of water required for mixing gypsum F, that moves over a scale (graduated in millimetres) attached
concrete when performing the setting time and compressive to the frame, A. The paste shall be held in a rigid conical ring,
strength tests. G, resting on a glass plate, H, about 100 mm square. The ring
C472−99 (2009)
FIG. 2 Consistometer
shall be made of a noncorroding, nonabsorbent material and 10.3 Procedure:
shall have an inside diameter of 70 mm at the base and 60 mm
10.3.1 Gypsum Concrete and All Gypsum Plasters, Except
at the top, and a height of 40 mm.
Gypsum Neat Plaster—Start the timing of the test approxi-
10.2.2 In addition, the Vicat apparatus shall conform to the
mately at the moment of contact of the dry material with the
following requirements:
water (see 5.1). Mix enough paste to fill the conical ring. For
Weight of plunger 300 ± 0.5 g the quantity of water and directions for mixing, see Section 8,
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