ASTM C531-18(2023)
(Test Method)Standard Test Method for Linear Shrinkage and Coefficient of Thermal Expansion of Chemical-Resistant Mortars, Grouts, Monolithic Surfacings, and Polymer Concretes
Standard Test Method for Linear Shrinkage and Coefficient of Thermal Expansion of Chemical-Resistant Mortars, Grouts, Monolithic Surfacings, and Polymer Concretes
SIGNIFICANCE AND USE
4.1 This test method offers a means of comparing the relative linear shrinkage and coefficient of thermal expansion.
4.1.1 The material to be tested is placed in the mold in a fluid or plastic state. As the material makes a transition to a solid state, it adheres to and captures the end studs.
4.1.2 The linear shrinkage measured is the change in length that occurs after the material is rigid enough and strong enough to move the studs.
4.2 This test method can be used for research purposes to provide information on linear changes taking place in the test materials. Other dimensional changes may occur that do not manifest themselves as changes in length.
SCOPE
1.1 This test method covers the measurement of the linear shrinkage during setting and curing and the coefficient of thermal expansion of chemical-resistant mortars, grouts, monolithic surfacings, and polymer concretes.
1.2 A bar of square cross-section is cast to a prescribed length in a mold that holds measuring studs that are captured in the ends of the finished casting.
1.2.1 The change in length after curing is measured and used to calculate shrinkage.
Note 1: Shrinkage determinations should not be made on sulfur mortars, since this test method cannot truly reflect the overall linear shrinkage of a sulfur mortar.
1.2.2 The change in length at a specific elevated temperature is measured and used to calculate the coefficient of thermal expansion.
1.3 This test method is limited to materials with aggregate size of 0.25 in. (6 mm) or less.
1.4 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.6 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.
General Information
Relations
Standards Content (Sample)
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: C531 − 18 (Reapproved 2023)
Standard Test Method for
Linear Shrinkage and Coefficient of Thermal Expansion of
Chemical-Resistant Mortars, Grouts, Monolithic Surfacings,
and Polymer Concretes
This standard is issued under the fixed designation C531; 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 mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This test method covers the measurement of the linear
shrinkage during setting and curing and the coefficient of
2. Referenced Documents
thermal expansion of chemical-resistant mortars, grouts, mono-
2.1 ASTM Standards:
lithic surfacings, and polymer concretes.
C287 Specification for Chemical-Resistant Sulfur Mortar
1.2 A bar of square cross-section is cast to a prescribed
(Withdrawn 2021)
length in a mold that holds measuring studs that are captured in
C490 Practice for Use of Apparatus for the Determination of
the ends of the finished casting.
Length Change of Hardened Cement Paste, Mortar, and
1.2.1 The change in length after curing is measured and
Concrete
used to calculate shrinkage.
C904 Terminology Relating to Chemical-Resistant Nonme-
NOTE 1—Shrinkage determinations should not be made on sulfur
tallic Materials
mortars, since this test method cannot truly reflect the overall linear
E177 Practice for Use of the Terms Precision and Bias in
shrinkage of a sulfur mortar.
ASTM Test Methods
1.2.2 The change in length at a specific elevated temperature
E691 Practice for Conducting an Interlaboratory Study to
is measured and used to calculate the coefficient of thermal
Determine the Precision of a Test Method
expansion.
3. Terminology
1.3 This test method is limited to materials with aggregate
size of 0.25 in. (6 mm) or less.
3.1 Definitions—For definitions of terms used in this test
method, see Terminology C904.
1.4 The values stated in inch-pound units are to be regarded
as standard. The values given in parentheses are mathematical
4. Significance and Use
conversions to SI units that are provided for information only
and are not considered standard.
4.1 This test method offers a means of comparing the
relative linear shrinkage and coefficient of thermal expansion.
1.5 This standard does not purport to address all of the
4.1.1 The material to be tested is placed in the mold in a
safety concerns, if any, associated with its use. It is the
fluid or plastic state. As the material makes a transition to a
responsibility of the user of this standard to establish appro-
solid state, it adheres to and captures the end studs.
priate safety, health, and environmental practices and deter-
4.1.2 The linear shrinkage measured is the change in length
mine the applicability of regulatory limitations prior to use.
that occurs after the material is rigid enough and strong enough
1.6 This international standard was developed in accor-
to move the studs.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4.2 This test method can be used for research purposes to
Development of International Standards, Guides and Recom-
provide information on linear changes taking place in the test
1 2
This test method is under the jurisdiction of ASTM Committee D01 on Paint For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and Related Coatings, Materials, and Applications and is the direct responsibility of contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Subcommittee D01.46 on Industrial Protective Coatings. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Oct. 1, 2023. Published October 2023. Originally the ASTM website.
approved in 1963. Last previous edition approved in 2018 as C531 – 18. DOI: The last approved version of this historical standard is referenced on
10.1520/C0531-18R23. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C531 − 18 (2023)
materials. Other dimensional changes may occur that do not 6.4.3 Measure the lengths of the studs with a micrometer to
manifest themselves as changes in length. 60.0001 in. (0.0025 mm).
6.4.4 In assembling the mold, the end blocks must move
5. Apparatus freely in the mold before securing to the mold with machine
screws.
5.1 Weighing Equipment, shall be capable of weighing
6.4.5 Measure the measuring studs with micrometers and
materials or specimens to 60.3 % accuracy.
carefully adjust in the end blocks by means of the standard bar
5.2 Equipment for Mixing, consisting of a container of
supplied with the mold.
suitable size preferably made of corrosion-resistant metal, or a
6.4.6 Fill the molds with the material, taking care to
porcelain pan, and a sturdy spatula or trowel.
eliminate air pockets by working the material with a spatula or
thin trowel. Level the top surface with the spatula and strike off
5.3 Specimen Mold, (see Practice C490) permitting the
molding of bars with a metal stud embedded in each end. The the excess evenly. In the case of sulfur mortars, at least three
separate pourings shall be made.
bars shall be 1 in. (25 mm) square by 10 in. (250 mm) between
studs when molded. A standard 10 in. (250 mm) metal bar shall 6.4.7 After casting the specimens, remove the machine
screws holding the end blocks to permit free movement of the
be provided; this is used to space the studs.
blocks.
5.4 Studs—Nickel alloy studs, which have linear coefficient
−6 −6
of thermal expansion of 7.2 × 10 per °F (4 × 10 per °C),
7. Conditioning
knurled on one end and threaded on the other (for securing in
7.1 Resin and Sulfur Materials—Test specimens shall be
end blocks), approximately 0.8 in. (20 mm) long. Remove any
removed from molds only after an initial curing time deemed
machining burrs from the flat end of the stud.
suitable by the manufacturer.
5.5 Comparator—A direct-reading dial or digital microm-
7.2 Silica and Silicate Materials—Immediately after mold-
eter to permit readings to 0.0001 in. (0.0025 mm).
ing the specimens, cover the mold with polyethylene sheeting
5.6 Micrometers, one having a range suitable for measuring
or other suitable material to prevent rapid evaporation of
the studs (0.8 in.), and one having a range suitable for
surface moisture and subsequent deformation of the specimen
measuring the standard 10 in. (254 mm) bar, both readable to
bar. Disassemble the mold (deviations in the time mortars, etc.
0.0001 in. (0.0025 mm).
are kept in the mold, are to be reported) as described in 7.1.
5.7 Constant-Temperature Oven—An oven capable of at-
8. Procedure for Linear Shrinkage
taining temperatures to 210 °F (99 °C) is required. The oven
should be capable of maintaining a set temperature constant to 8.1 Determine the length of the bar by inserting it in the
63 °F (61.5 °C). length comparator.
NOTE 2—In cases where shrinkage in the specimens is great enough that
6. Test Specimens
comparator readings are no longer possible, insertion of a spacer (such as
a metal washer) under the bottom stud holder of the comparator will
6.1 Temperature—The standard temperature of the product
enable readings to be made. When this is necessary, standard bar readings
constituents, mold apparatus, and the temperature in the
will also change and proper adjustments in calculation must be made.
vicinity of the mixing operation shall be 73 °F 6 4 °F (23 °C
8.2 The frequency of shrinkage measurement depends on
6 2 °C), unless otherwise specified by the manufacturer. The
the information desired; for example, if it is desired to follow
actual temperature shall be recorded.
the shrinkage at room temperature, or at a specific temperature,
6.2 Number of Specimens—A minimum of four test bar
readings can be made as long as shrinkage continues. A typical
specimens shall be prepared for each material tested.
schedule is as follows: daily for 2 weeks at 73 °F 6 4 °F (23 °C
6.3 Preparation of Materials: 6 2 °C), then after 3 days at 210 °F (99 °C) or 140 °F (60 °C),
depending on the material (see 9.2). If the specimens are heated
6.3.1 Mix the material in the proportions specified by the
manufacturer of the materials. If the proportions so specified to induce cure, cool overnight at 73 °F (23
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