ASTM C307-23

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Designation: C307 − 18 C307 − 23
Standard Test Method for
Tensile Strength of Chemical-Resistant Mortar, Grouts, and
Monolithic Surfacings
This standard is issued under the fixed designation C307; 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 test method covers the determination of tensile strength of cured chemical-resistant materials in the form of molded
briquets. These materials include mortars, brick and tile grouts, machinery grouts, and monolithic surfacings. These materials shall
be based on resin, silicate, silica, or sulfur binders.
1.2 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.
1.3 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.
1.4 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.
2. Referenced Documents
2.1 ASTM Standards:
C904 Terminology Relating to Chemical-Resistant Nonmetallic Materials
E4 Practices for Force Calibration and Verification of Testing Machines
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this test method, see Terminology C904.
This test method is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.46 on Industrial Protective Coatings.
Current edition approved July 1, 2018June 1, 2023. Published November 2018June 2023. Originally published in 1953. Last previous edition approved in 20122018 as
C307C307 – 18. – 03 (2012). DOI: 10.1520/C0307-18. DOI: 10.1520/C0307-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
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C307 − 23
4. Significance and Use
4.1 It is recognized that chemical-resistant mortars, grouts, and monolithic surfacings are not usually under tension when in
service; however, such data are useful for purposes of determining the rate of cure and other properties.
4.2 This test method is not recommended for mortars, grouts, and monolithic surfacings containing aggregate greater than ⁄4 in.
5. Apparatus
5.1 Weighing Equipment, shall be capable of weighing materials or specimens to 60.3 % accuracy.
5.2 Specimen Molds—The molds for making briquet test specimens shall be sufficiently rigid to prevent deformation during
molding and shall be made of corrosion-resistant material. Gang molds, when used, shall be of the type shown in Fig. 1. The
dimensions of the briquet molds shall be the width of the mold, between inside faces, at waist line of briquet, 1 in. The width and
the depth of the briquet mold at the waist line shall be 1 in. 6 0.02in. (25mm 6 0.5mm).0.02 in. (25 mm 6 0.5 mm). The molds
shall conform to the dimensional requirements shown in Fig. 2.
5.3 Equipment for Mixing Materials, shall consist of a container of suitable size, preferably corrosion resistant, and a strong, sturdy
spatula, trowel, or mechanical mixer.
5.4 The following additional equipment is required for sulfur mortars.
5.4.1 Melting Chamber, of sufficient volume and heat capacity to melt the mortar sample and maintain the temperature of the melt
between 260 and 290°F (127 and 143°C).260 °F and 290 °F (127 °C and 143 °C).
5.4.2 Laboratory Mixer, of such a type and speed to be capable of lifting the aggregate without beating air into the melt.
5.4.3 Ladle, of sufficient capacity to completely pour one briquet.
5.5 Testing Machine, the testing machine shall be of any type sufficient to provide the required load and the rate of crosshead
movement prescribed. It shall have been verified to have an accuracy of 1.0 % or better within 12 months of the time of use in
accordance with Practices E4.
5.6 Tension Clips, for holding the tension test specimens, shall be in accordance with Fig. 3.
6. Test Specimens
6.1 All specimens for a single determination shall be made from a single mix containing sufficient amounts of the components
in the proportions and in the manner specified by the manufacturer of the materials. If the proportions so specified are by volume,
the constituents shall be weighed and the corresponding proportions by weight shall be reported.
6.1.1 Number of Specimens—Prepare a minimum of six briquet specimens for each material tested.
6.2 Temperature:
FIG. 1 Briquet Gang Mold
The sole source of supply of the Forney capping compound melting chamber, Model LA-0130, known to the committee at this time is Forney Industries, Inc., 1565
Broadway Ave., Hermitage, PA 16148. If you are aware of alternative suppliers, please provide this information to ASTM Headquarters. Your comments will receive careful
consideration at a meeting of the responsible technical committee, which you may attend.
C307 − 23
FIG. 2 Briquet Specimens for Tensile Strength Test
6.2.1 Resin, Silicate, and Silica Materials—The standard temperature of the materials, molds apparatus, and the ambient
temperature of the mixing area shall be 73 6 4°F (23 6 2°C).73 °F 6 4 °F (23 °C 6 2 °C). Record the actual temperature.
6.2.2 Sulfur Mortars—The material shall be maintained at 275 6 15°F (135 6 8°C).275 °F 6 15 °F (135 °C 6 8 °C). The
temperature of the molds and the ambient temperature of the mixing area shall be 73 6 4°F (23 6 2°C).73 °F 6 4 °F (23 °C 6
2 °C). Record the actual temperature.
6.3 Molding Test Specimens:
6.3.1 Assemble and lubricate the mold by applying a thin film of an appropriate mold release or lubricant like silicone stop-cock
grease or petroleum jelly.
6.3.2 Resin, Silicate, and Silica Materials—Mix a sufficient amount of the components in the proportions and in the manner
specified by the manufacturer of the materials. Fill the molds one-half full. Remove any entrapped air by using a cutting and
stabbing motion with a spatula or rounded-end rod. Fill the remainder of the mold, working down into the previously placed
portion. Upon completion of the filling operations, the tops of the specimens should extend slightly above the tops of the molds.
When the molds have been filled, strike off the excess material so that it is even with the top of the mold. Permit the material to
remain in the mold until it has set sufficiently to allow removal without danger of deformation or breakage.
6.3.3 Silicate Materials—Some silicates may require covering during the curing period. After removal from the molds, acid-treat
the specimens, if required, in accordance with the recommendations given by the manufacturer. No other treatment shall be
permitted. Record the method of treatment in the report section under Conditioning Procedure.
6.3.4 Sulfur Mortars:
6.3.4.1 Assemble the mold in 6.3.1.
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