ASTM D8212-24
(Practice)Standard Practice for Determination of the Radial Tensile Properties of Geogrids Under Low Radial Strain
Standard Practice for Determination of the Radial Tensile Properties of Geogrids Under Low Radial Strain
SIGNIFICANCE AND USE
4.1 The determination of the tensile force-elongation values of geogrids provides index property values. This standard practice shall be used for the determination of radial properties, judgment of conformity of product manufactured, and acceptance of commercial shipments of geogrids.
4.2 The standard strain at which this practice is applied is 2 %, as this has been established and accepted over the years as the lowest strain at which consistent measurement of the properties of geogrids can be achieved. However, if a customer or specifier requires calculation at a lower strain, this can be done provided the higher standard deviation this can give is accepted.
4.3 In cases of dispute arising from differences in reported results when using this standard practice for acceptance testing of commercial shipments, the purchaser and supplier should conduct comparative tests and calculations to determine if there is a statistical bias between their laboratories. Competent statistical assistance is recommended for the investigation of bias. As a minimum, the two parties should take a group of test specimens which are as homogeneous as possible and which are from a lot of material of the type in question. The test specimens should then be randomly assigned in equal numbers to each laboratory for testing. The average results from the two laboratories should be compared using Student's t-test for unpaired data and an acceptable probability level chosen by the two parties before the testing began. If a bias is found, either its cause must be found and corrected or the purchaser and supplier must agree to interpret future results in light of the known bias.
4.4 This standard practice is applicable to all geogrids with two or three sets of ribs in which variation of tensile properties between different sets of parallel ribs is 20 % or less. For multiple-layered geogrids, it should be applied to each layer individually and the results for all layers summed in each radial di...
SCOPE
1.1 This practice presents a method for determining in-air index values (see Note 1) of the radial load and radial stiffness at low strain in each symmetric direction of a balanced geogrid (see Note 2) subjected to 360° radial strain. This determination is based on tensile test results from testing in accordance with Test Method D6637/D6637M and an analysis of the radial force balance in each symmetric direction across a circle of geogrid that is assumed to be strained uniformly in all radial directions to a low strain level.
1.2 Symmetric directions relative to the machine direction:
1.2.1 For geogrids with square or rectangular apertures: 0°, 45°, 90°, 135°.
1.2.2 For geogrids with triangular apertures: 0°, 30°, 60°, 90°, 120°, 150°.
Note 1: These index properties are not to be used for design or performance purposes.
Note 2: A balanced geogrid is one in which the manufacturer’s specification indicates that variation of tensile properties between different sets of parallel ribs is 20 % or less.
1.3 This practice will facilitate comparisons of the radial tensile properties of different balanced geogrids and judgment of conformity of product manufactured and acceptance of commercial shipments of geogrids by standardizing the data used and the method by which the calculations are performed.
1.4 This standard practice is restricted in application to geogrids with two sets of parallel ribs arranged at nominally 90° to each other or three sets of parallel ribs arranged at nominally 60° to each other with one set lying in the cross-machine direction.
1.5 Further, this practice is restricted to 20 % variation in the specified unit tensile properties of the different sets of ribs in a geogrid in order to enable the development of the mathematics that use these properties of each set of ribs in the geogrid. This generates index values for the unit tensile properties in the nominal directions as outlined in ...
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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: D8212 − 24
Standard Practice for
Determination of the Radial Tensile Properties of Geogrids
1
Under Low Radial Strain
This standard is issued under the fixed designation D8212; 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 1.2.2 of a geogrid that is under 360° radial strain at any
designated strain level. A 2 % strain level is set as the default
1.1 This practice presents a method for determining in-air
strain of choice as it has been found that this is the lowest strain
index values (see Note 1) of the radial load and radial stiffness
level at which most test laboratories can achieve consistent
at low strain in each symmetric direction of a balanced geogrid
low-strain tensile test results on geogrids.
(see Note 2) subjected to 360° radial strain. This determination
is based on tensile test results from testing in accordance with 1.6 Calculations in accordance with this practice determine
Test Method D6637/D6637M and an analysis of the radial the radial component of the unit tensions generated in the
force balance in each symmetric direction across a circle of geogrid. Differences in the unit tensions of different rib sets
geogrid that is assumed to be strained uniformly in all radial will also give tangential components of force. With a difference
directions to a low strain level. in tension between rib sets restricted to 20 % or less, it has been
found that these tangential components will be approximately
1.2 Symmetric directions relative to the machine direction:
10 % or less of the values of the radial components. Therefore,
1.2.1 For geogrids with square or rectangular apertures: 0°,
the resultant of the radial and tangential component in any
45°, 90°, 135°.
symmetric direction will be less than 0.5 % greater than the
1.2.2 For geogrids with triangular apertures: 0°, 30°, 60°,
radial component. As this is less than the variation normally
90°, 120°, 150°.
found in tensile testing of a set of rib or wide-width specimens,
NOTE 1—These index properties are not to be used for design or
it does not detract from the calculated radial tensions being
performance purposes.
valid index properties of the geogrid.
NOTE 2—A balanced geogrid is one in which the manufacturer’s
specification indicates that variation of tensile properties between different
1.7 This practice is not applicable to uniaxial geogrids.
sets of parallel ribs is 20 % or less.
1.8 The values stated in SI units are to be regarded as the
1.3 This practice will facilitate comparisons of the radial
standard. The values given in parentheses are for information
tensile properties of different balanced geogrids and judgment
only.
of conformity of product manufactured and acceptance of
1.9 This standard does not purport to address all of the
commercial shipments of geogrids by standardizing the data
safety concerns, if any, associated with its use. It is the
used and the method by which the calculations are performed.
responsibility of the user of this standard to establish appro-
1.4 This standard practice is restricted in application to
priate safety, health, and environmental practices and deter-
geogrids with two sets of parallel ribs arranged at nominally
mine the applicability of regulatory limitations prior to use.
90° to each other or three sets of parallel ribs arranged at
1.10 This international standard was developed in accor-
nominally 60° to each other with one set lying in the cross-
dance with internationally recognized principles on standard-
machine direction.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.5 Further, this practice is restricted to 20 % variation in
mendations issued by the World Trade Organization Technical
the specified unit tensile properties of the different sets of ribs
Barriers to Trade (TBT) Committee.
in a geogrid in order to enable the development of the
mathematics that use these properties of each set of ribs in the
2. Referenced Documents
geogrid. This generates index values for the unit tensile
2
2.1 ASTM Standards:
properties in the nominal directions as outlined in 1.2.1 and
D4439 Terminology for Geosynthetics
1
This practice is under the jurisdiction of ASTM Committee D35 on Geosyn-
2
thetics and is the direct responsibility of Subcommittee D35.01 on Mechanical For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Properties. contac
...
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: D8212 − 24
Standard Practice for
Determination of the Radial Tensile Properties of Geogrids
1
Under Low Radial Strain
This standard is issued under the fixed designation D8212; 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 1.2.2 of a geogrid that is under 360° radial strain at any
designated strain level. A 2 % strain level is set as the default
1.1 This practice presents a method for determining in-air
strain of choice as it has been found that this is the lowest strain
index values (see Note 1) of the radial load and radial stiffness
level at which most test laboratories can achieve consistent
at low strain in each symmetric direction of a balanced geogrid
low-strain tensile test results on geogrids.
(see Note 2) subjected to 360° radial strain. This determination
is based on tensile test results from testing in accordance with 1.6 Calculations in accordance with this practice determine
Test Method D6637/D6637M and an analysis of the radial the radial component of the unit tensions generated in the
force balance in each symmetric direction across a circle of geogrid. Differences in the unit tensions of different rib sets
geogrid that is assumed to be strained uniformly in all radial will also give tangential components of force. With a difference
directions to a low strain level. in tension between rib sets restricted to 20 % or less, it has been
found that these tangential components will be approximately
1.2 Symmetric directions relative to the machine direction:
10 % or less of the values of the radial components. Therefore,
1.2.1 For geogrids with square or rectangular apertures: 0°,
the resultant of the radial and tangential component in any
45°, 90°, 135°.
symmetric direction will be less than 0.5 % greater than the
1.2.2 For geogrids with triangular apertures: 0°, 30°, 60°,
radial component. As this is less than the variation normally
90°, 120°, 150°.
found in tensile testing of a set of rib or wide-width specimens,
NOTE 1—These index properties are not to be used for design or
it does not detract from the calculated radial tensions being
performance purposes.
valid index properties of the geogrid.
NOTE 2—A balanced geogrid is one in which the manufacturer’s
specification indicates that variation of tensile properties between different
1.7 This practice is not applicable to uniaxial geogrids.
sets of parallel ribs is 20 % or less.
1.8 The values stated in SI units are to be regarded as the
1.3 This practice will facilitate comparisons of the radial
standard. The values given in parentheses are for information
tensile properties of different balanced geogrids and judgment
only.
of conformity of product manufactured and acceptance of
1.9 This standard does not purport to address all of the
commercial shipments of geogrids by standardizing the data
safety concerns, if any, associated with its use. It is the
used and the method by which the calculations are performed.
responsibility of the user of this standard to establish appro-
1.4 This standard practice is restricted in application to
priate safety, health, and environmental practices and deter-
geogrids with two sets of parallel ribs arranged at nominally
mine the applicability of regulatory limitations prior to use.
90° to each other or three sets of parallel ribs arranged at
1.10 This international standard was developed in accor-
nominally 60° to each other with one set lying in the cross-
dance with internationally recognized principles on standard-
machine direction.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.5 Further, this practice is restricted to 20 % variation in
mendations issued by the World Trade Organization Technical
the specified unit tensile properties of the different sets of ribs
Barriers to Trade (TBT) Committee.
in a geogrid in order to enable the development of the
mathematics that use these properties of each set of ribs in the
2. Referenced Documents
geogrid. This generates index values for the unit tensile
2
2.1 ASTM Standards:
properties in the nominal directions as outlined in 1.2.1 and
D4439 Terminology for Geosynthetics
1
This practice is under the jurisdiction of ASTM Committee D35 on Geosyn-
2
thetics and is the direct responsibility of Subcommittee D35.01 on Mechanical For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Properties. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved Feb. 1, 2024. Published February 2024. DOI: 10.1520/ Standar
...
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