ASTM D8058-23

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Designation: D8058 − 19 D8058 − 23
Standard Test Method for
Determining the Flexural Strength of a Geosynthetic
Cementitious Composite Mat (GCCM) Using the Three-Point
Bending Test
This standard is issued under the fixed designation D8058; 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.
1. Scope
1.1 This test method provides guidelines for testing the flexural strength of cured geosynthetic cementitious composite mat
(GCCM) products in a three (3)-point bend apparatus.
1.2 The values in SI units are to be regarded as the standard. Values in inch-pound units are in parentheses for information.
1.3 This standard may involve hazardous operations, equipment, and climates. 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:
D76/D76M Specification for Tensile Testing Machines for Textiles
D4354 Practice for Sampling of Geosynthetics and Rolled Erosion Control Products (RECPs) for Testing
D4439 Terminology for Geosynthetics
D5994/D5994M Test Method for Measuring Core Thickness of Textured Geomembranes
D8030/D8030M Practice for Sample Preparation for GCCM
3. Terminology
3.1 For definitions of common technical terms used in this standard, refer to Terminology D4439.
3.2 Definitions:
3.2.1 cured, adj—a description of the state of a GCCM after hydration for a specified period of time and quantity of water when
known under specified conditions, followed by a period of time where the GCCM is kept under a specified environmental condition
during which the cementitious material continues to cure and develop compressive strength.
This test method is under the jurisdiction of ASTM Committee D35 on Geosynthetics and is the direct responsibility of Subcommittee D35.05 on Geosynthetic Erosion
Control.
Current edition approved Jan. 1, 2019Feb. 1, 2023. Published January 2019March 2023. Originally approved in 2017. Last previous edition approved in 20172019 as
D8058 – 17.D8058 – 19. DOI: 10.1520/D8058-19.10.1520/D8058-23.
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3.2.2 curing time, n—the time subsequent to initial hydration of the GCCM and immediately prior to the testing of the material,
during which the cementitious material is allowed to harden and form its final strength using the specific process for curing as
specified in 8.3.
3.2.3 dry, adj—a description of the state of a GCCM before it has been exposed to a hydration source and typically describes the
“as-received” dry product after conditioning in a prescribed manner.
3.2.3 final breaking load, n—the maximum load achieved prior to rupture of materials.materials, measured between 0 and 30 mm
(1.2 in.) of displacement from the start of the test.
3.2.4 final deflection—the deflection of the specimen from its initial position (before testing begins) measured at mid span at the
final breaking load.
3.2.5 final flexural strength, n—the final flexural strength, expressed in megapascals (pound-force per square inch), is calculated
from the final breaking load of a hydrated and cured GCCM specimen, oriented in either the machine or cross-machine direction,
loaded as simple beams, when breaks occur perpendicular to the specimen length, with the load applied at the center, in a
three-point loading fixture.
3.2.6 geosynthetic cementitious composite barrier (GCCB), n—a composite material consisting of a geosynthetic barrier bonded
to an integral GCCM protective cover layer. The geosynthetic barrier component of adjacent material must be seamed to reduce
or prevent the flow of fluid through the construction.
3.2.6.1 Discussion—
The terms geosynthetic barrier,GCCM, and seam are defined in Terminology D4439.
3.2.7 hydration, n—exposure of the GCCM, in this case, to water in prescribed conditions for a prescribed time and water quantity
when known.
3.2.8 initial breaking load, n—the maximum load at which the first crack in the cementitious matrix of the GCCM forms.forms
(the first recorded zero slope on a load/displacement graph), measured between 0 and 2 mm (0.08 in.) displacement from the start
of the test.
3.2.9 initial deflection, n—the deflection of the specimen from its initial position (before testing begins) measured at mid span at
the initial breaking load.
3.2.10 initial flexural strength, n—the initial flexural strength, expressed in megapascals (pound-force per square inch), is
calculated from the initial breaking load (maximum load at first crack) of a hydrated and cured GCCM specimen, oriented in either
the machine or cross-machine direction, loaded as simple beams, with the load applied at the center, in a three-point loading fixture.
3.2.11 initial modulus of elasticity, n—a measure of a specimen’s resistance to elastic deformation, measured in the region of linear
response, before the initial breaking load.
3.2.12 mean final flexural strength, n—the mean final flexural strength is the average result of ten or more final flexural strength
values expressed in megapascals (pound-force per square inch).
3.2.13 mean initial flexural strength, n—the mean initial flexural strength is the arithmetic mean of ten or more initial flexural
strength values when breaks occur perpendicular to the specimen length. Breaks expressed in megapascals (pound-force per square
inch).
3.2.14 topside, n—the side of the material that would face upwards in a normal installation.
4. Summary of Test Method
4.1 A hydrated and cured GCCM specimen is loaded as a simple beam in a three-point loading fixture, with the load applied at
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the center. The load level is recorded simultaneously with the deflection to characterize the initial and final flexural strength, the
deflection of the specimen at those loads, and the initial modulus of the specimen.
5. Significance and Use
5.1 This test method is applicable for testing geosynthetic cementitious composite mats in a cured state. It is used with a constant
rate of extension-type constant-rate-of-extension type tension apparatus.
5.2 This test is an index test that may be used for manufacturing quality control (MQC). This test is appropriate for characterizing
the flexural properties of a GCCM.
6. Apparatus
6.1 Flexural Testing Machine—A constant rate of extension (CRE)-type of testing machine described in Specification D76/D76M
shall be used. When using the CRE-type tensile tester, the recorder must have adequate pen response to properly record the
force-elongation curve as specified in Specification D76/D76M.
6.2 Three-Point Flexural Fixture—A fixture designed for use with the flexural testing machine with two bottom supports and a
third edge which is used to load the specimen from the top at mid span. The fixture is designed so that the specimen is loaded and
can be analyzed as a simple beam. The supports are cylindrical on the specimen contact surface with a 3.2-mm3.2 mm ( ⁄8-in.) in.)
minimum radius and a 12.7-mm 12.7 mm ( ⁄2-in.) in.) maximum radius. These support points must be designed fixed, polished,
and cleaned so that they cannot exert longitudinal or vertical constraints (rocker-type bearing edges, rollers, etc.). The loading
surface must have a similar edge bearing. The test span shall be 100 6 1.6 mm (4 6 ⁄16 in.) and the load line and support shall
be parallel. Mount a dial micrometer reading to 0.25 mm (0.01 in.), 0.25 mm (0.01 in.), or an equally sensitive apparatus, to bear
on the loading member or on the specimen at mid span to determine the deflection of the specimen at the center of the test span
as the load is measured.
6.3 Sample Containers—Suitable containers which are resistant to corrosion and change in mass upon repeated exposure to
moisture, materials of varying pH, and cleaning.
6.4 Die—A sample-cutting device of dimensions consistent with 8.2.
6.5 Rotary Tile Saw, with diamond-tipped blades capable of dry cutting samples, used for cutting cured samples to predetermined
dimensions using pattern marked on cured specimen with template and markers.
6.6 Miscellaneous – Knives, Templates, Markers, Rulers, Saw, as required for marking, measuring, and cutting specimens to fixed
dimensions before measurement of weight. A knife with a “snap off” type blade is recommended for cutting GCCMs, which can
dull blade tips rapidly.
6.7 Thickness Gage—Gauge and Thickness Gauge Points—A measurement device for characterizing the thickness of the
specimens in the vicinityAs described in Test Method D5994/D5994Mof the breaks which occur during the flexural test. The
thickness gage shall have flat parallel anvils of between 10-mm (0.4-in.) and 15-mm (0.6-in.) diameter with an accuracy of 60.05
mm (60.002 in.).
6.8 Micrometer—A calibrated measurement device used for precise measurement of components with a required accuracy of
60.25 mm (60.01 in.), or an equally sensitive apparatus.
7. Sampling, Test Specimens, and Test Units
7.1 Lot Sample—For the lot sample, refer to Practice D4354 for discussion of recommended practice for breaking up shipments
of GCCMs into lots for testing.
7.2 Laboratory Samples—For the laboratory sample, take a full-width sample approximately 1 m (40 in.) long in the machine
direction from each roll in the lot sample. The exact length must be chosen to ensure enough sample is cured to cut the required
number of specimens for both the machine and cross-machine directions. The sample may be taken from the end portion of a roll,
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provided there is no evidence it is distorted or different from other portions of the roll. In cases of dispute, take a sample that will
exclude material from the outer wrap of the roll or the inner wrap around the core, of at least 30 in. from the interior end of the
roll (wrapped around the core) or exterior end of the material roll, measured from the edge of the cementitious portion of the
material.
7.3 Test Specimens—For tests in the machine direction and the cross-machine direction, respectively, take from each sample in the
laboratory sample the number of specimens directed in Section 8. Take specimens at random from the laboratory sample, with
those for the measurement of the machine direction tensile properties from different positions across the sample width, and the
specimens for the measurement of the cross-machine direction tensile properties from different positions along the length of the
sample. Specimens must not be taken near the edge of the material. Specimens must be taken a m
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