ASTM D5262-07(2012)
(Test Method)Standard Test Method for Evaluating the Unconfined Tension Creep and Creep Rupture Behavior of Geosynthetics
Standard Test Method for Evaluating the Unconfined Tension Creep and Creep Rupture Behavior of Geosynthetics
SIGNIFICANCE AND USE
5.1 This test method is developed for use in the determination of anticipated total elongation or time to rupture that may occur in geosynthetics under sustained loading conditions.
5.1.1 The test data can be used in conjunction with interpretive methods to evaluate creep strain potential at design loads.
5.1.2 The test data can be used in conjunction with interpretive methods to evaluate creep rupture potential at various loads.
5.2 This test method is not intended for routine acceptance testing of geosynthetics. This test method should be used to characterize geosynthetics intended for use in applications in which creep or creep rupture is of concern. The plane strain or rupture condition imposed during testing must be considered when using the test results for design.
5.3 The basic distinctions between this test method and other test methods for measuring tension creep and creep rupture behavior are (1) the width of the specimens (Section 8) and (2) the measurement of total elongation or time to rupture from the moment of specimen loading. The greater widths of the specimens specified in this test method minimize the contraction edge effect (necking) that occurs in many geosynthetic materials and provides a closer relationship to actual material behavior in plane strain tension conditions.
5.4 The creep or stress rupture of a given geosynthetic is likely to be reduced in soil because of load transfer to the soil. The unconfined environment represents a controlled test, in which the results are conservative with regard to the behavior of the material in service. Confined or in-soil testing may model the field behavior of the geosynthetic more accurately.
SCOPE
1.1 This test method is intended for use in determining the unconfined tension creep and creep rupture behavior of geosynthetics at constant temperature when subjected to a sustained tensile loading. This test method is applicable to all geosynthetics.
1.2 The test method measures total elongation of the geosynthetic test specimen, from the time of loading, while being maintained at a constant temperature. It includes procedures for measuring the tension creep and creep rupture behavior at constant temperature of conditioned geosynthetics as well as directions for calculating tension creep and creep rupture curves.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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.
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Designation:D5262 −07(Reapproved 2012)
Standard Test Method for
Evaluating the Unconfined Tension Creep and Creep
Rupture Behavior of Geosynthetics
This standard is issued under the fixed designation D5262; 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 D4491 Test Methods for Water Permeability of Geotextiles
by Permittivity
1.1 This test method is intended for use in determining the
D4595 Test Method for Tensile Properties of Geotextiles by
unconfined tension creep and creep rupture behavior of geo-
the Wide-Width Strip Method
synthetics at constant temperature when subjected to a sus-
D6637 Test Method for Determining Tensile Properties of
tained tensile loading. This test method is applicable to all
Geogrids by the Single or Multi-Rib Tensile Method
geosynthetics.
E6 Terminology Relating to Methods of Mechanical Testing
1.2 The test method measures total elongation of the geo-
synthetic test specimen, from the time of loading, while being
3. Terminology
maintained at a constant temperature. It includes procedures
3.1 Definitions—For definitions of many terms used in this
for measuring the tension creep and creep rupture behavior at
test method, refer to Terminologies D123, D4439 and E6.
constant temperature of conditioned geosynthetics as well as
3.2 Definitions of Terms Specific to This Standard:
directions for calculating tension creep and creep rupture
3.2.1 atmosphere for testing geosynthetics, n—air main-
curves.
tained at a relative humidity between 50 and 70 % and the test
1.3 The values stated in SI units are to be regarded as the
(Section 10.2).
standard. The values given in parentheses are for information
3.2.2 creep,n—thetime-dependentincreaseinaccumulative
only.
strain in a material resulting from an applied constant force.
1.4 This standard does not purport to address all of the
3.2.3 design load, n—the load at which the geosynthetic is
safety concerns, if any, associated with its use. It is the
required to operate in order to perform its intended function.
responsibility of the user of this standard to establish appro-
3.2.4 failure, n—an arbitrary point at which a material
priate safety and health practices and determine the applica-
ceases to be functionally capable of its intended use.
bility of regulatory limitations prior to use.
3.2.5 geogrid, n—a geosynthetic formed by a regular net-
work of integrally connected elements with apertures greater
2. Referenced Documents
than 6.35 mm ( ⁄4 in.) to allow interlocking with surrounding
2.1 ASTM Standards:
soil, rock, earth, and other surrounding materials to function
D123 Terminology Relating to Textiles
primarily as reinforcement.
D1776 Practice for Conditioning and Testing Textiles
3.2.6 geomembrane,n—anessentiallyimpermeablegeosyn-
D2990 Test Methods for Tensile, Compressive, and Flexural
thetic composed of one or more synthetic sheets.
Creep and Creep-Rupture of Plastics
3.2.6.1 Discussion—In geotechnical engineering, essen-
D4354 Practice for Sampling of Geosynthetics and Rolled
tially impermeable means that no measurable liquid flows
Erosion Control Products(RECPs) for Testing
through a geosynthetic when tested in accordance with Test
D4439 Terminology for Geosynthetics
Methods D4491.
3.2.7 geosynthetic, n—a planar product manufactured from
1 polymeric material used with soil, rock, earth, or other geo-
This test method is under the jurisdiction of ASTM Committee D35 on
Geosynthetics and is the direct responsibility of Subcommittee D35.02 on Endur- technical engineering-related material as an integral part of a
ance Properties.
man-made project, structure, or system.
Current edition approved July 1, 2012. Published July 2012. Originally approved
3.2.8 geotextile, n—a permeable geosynthetic comprised
in 1992. Last previous edition approved in 2007 as D5262 – 07. DOI: 10.1520/
D5262-07R12.
solely of textiles.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.2.8.1 Discussion—Current manufacturing techniques pro-
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
duce nonwoven fabrics, knitted (non-tubular) fabrics, and
Standardsvolume information, refer to the standards’s Document Summary page on
the ASTM website. woven fabrics.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5262−07 (2012)
3.2.9 index test, n—a test procedure that may contain a 6.1.1 Clamps should be at least as wide as the specimen,
known bias, but that may be used to establish an order for a set with appropriate clamping power that will prevent slipping or
of specimens with respect to the property being measured. damage of the test specimen within or at the faces of the
clamps. The clamps and clamping technique shall be designed
3.2.10 rate of creep, n—the slope of the creep-time curve at
to minimize eccentric loading of the specimen. A swivel or
a given time.
universal joint shall be used on one of the clamps at the end of
−1
3.2.11 tensile creep rupture strength, [FL ],n—for
the specimen. It is recommended that clamps permit the final
geosynthetics, the force per unit width that will produce failure
centering of the specimen prior to application of the load.
byruptureinacreeptestinagiventime,ataspecifiedconstant
6.1.2 Geotextiles and Geomembranes —Each clamp shall
environment.
be sufficiently wide to grip the entire width of the specimen,
3.2.12 tensile creep strain, n—the total strain at any given
200 mm (8.0 in.), and a minimum of 50-mm (2.0-in.) length in
time.
the direction of the applied force.
6.1.3 Geogrids—These should be clamped to assure com-
3.2.13 wide strip tensile test, n—for geosynthetics, a tensile
test in which the entire width of a 200-mm (8.0 in.)-wide plete tension load transfer through test direction members. The
specimen is gripped in the clamps with a gage length of 100 type of clamp and load transfer mechanism should be detailed
in the test report. Roller grips or low melting point alloy with
mm (4.0 in.).
adequate strength may be used to assist proper clamping. See
4. Summary of Test Method
Test Method D6637.
4.1 The tension creep and creep rupture behavior of geo-
6.1.4 Other Related Products—Where special clamps are
synthetics is measured by applying a sustained load in one step used to grip these products, they should conform to the general
and measuring the total elongation of the test specimen as a
requirements for clamps used to grip geotextiles,
function of time while maintaining a specified temperature and geomembranes, and geogrids, and the clamping methods used
humidity.
should always be detailed in the report.
6.2 Loading System—The loading system must be designed
5. Significance and Use
so that the load applied and maintained on the specimen is
5.1 This test method is developed for use in the determina-
within 61 % of the desired load. Loads may be applied by
tion of anticipated total elongation or time to rupture that may
weights, weights and fulcrums, or pneumatics. The loading
occur in geosynthetics under sustained loading conditions.
mechanism must permit reproducibly rapid and smooth
5.1.1 The test data can be used in conjunction with inter-
loading, as specified in 11.4. No dynamic forces on placement
pretive methods to evaluate creep strain potential at design
of the loads shall be allowed. Provision must also be made to
loads.
ensure that shock loading, caused by specimen failure, is not
5.1.2 The test data can be used in conjunction with inter-
transferred to other specimens undergoing testing.
pretive methods to evaluate creep rupture potential at various
6.3 Extension Measurement—Extensometers are preferred
loads.
for the measurement of elongation in geosynthetics. Whenever
5.2 This test method is not intended for routine acceptance
possible, other means of measuring elongation should be
testing of geosynthetics. This test method should be used to
calibrated against extensometers. In any case, the device
characterize geosynthetics intended for use in applications in
chosen shall be capable of measuring deformations to an
which creep or creep rupture is of concern. The plane strain or
accuracy of at least 0.003 6 mm (0.0001 6 in.). The means of
rupture condition imposed during testing must be considered
measuring elongation should be indicated clearly in the report.
when using the test results for design.
6.4 Vibration Control—Creep and creep rupture tests are
5.3 The basic distinctions between this test method and
sensitive to shock and vibration. The location of the apparatus,
other test methods for measuring tension creep and creep
test equipment, and mounting shall be designed so that the
rupture behavior are (1) the width of the specimens (Section 8)
specimen is isolated from vibration. Multi-station test equip-
and (2) the measurement of total elongation or time to rupture
ment must be of sufficient rigidity so that no significant
from the moment of specimen loading. The greater widths of
deflection due to shock or vibration occurs during testing.
the specimens specified in this test method minimize the
6.5 Time Measurement—The accuracy of the time measur-
contraction edge effect (necking) that occurs in many geosyn-
ing device shall be 61 % of the elapsed time of each creep or
thetic materials and provides a closer relationship to actual
creep rupture measurement load increment.
material behavior in plane strain tension conditions.
6.6 Temperature Control and Measurement:
5.4 The creep or stress rupture of a given geosynthetic is
6.6.1 The temperature in the test space, especially close to
likely to be reduced in soil because of load transfer to the soil.
the gage length of the specimen, shall be maintained within
The unconfined environment represents a controlled test, in
62.0°C (63.6°F) of the targeted value by a suitable automatic
which the results are conservative with regard to the behavior
device and shall be stated in the report. It is generally
of the material in service. Confined or in-soil testing may
model the field behavior of the geosynthetic more accurately.
6. Apparatus
Examples of clamping, loading, and extensometer systems that have been used
6.1 Clamps: successfully are found in the appendixes.
D5262−07 (2012)
recognized that thermal contraction and expansion, associated 8.1.1 Geotextiles—Prepare specimen width to 200 mm (8.0
with small temperature changes during the test, may produce in) wide by at least 200 mm (8.0 in) long.
changes in the apparent creep rate, especially near the transi- 8.1.2 Geogrids—Prepare specimen width to include at least
tion temperature. three longitudinal elements abreast parallel to the direction that
the creep or creep rupture behavior is being measured with
6.6.2 Temperature measurements shall be recorded at fre-
each element long enough to include at least three apertures, as
quent intervals, or recorded continuously, in order to ensure an
illustrated in Fig. X2.1.
accurate determination of the average test temperature and
compliance with 6.6.1.
8.2 The length of the specimen depends on the type of
clamps being used. The specimen must be long enough to
6.7 Environmental Control and Measurement:
extend through the full length of both clamps, as determined
6.7.1 When the test environment is air, the relative humidity
for the direction of the test.
shall be maintained between 50 and 70 % unless the creep or
creep rupture behavior of the geosynthetic has been shown to
8.3 When specimen integrity is not affected, the specimen
be unaffected by humidity. The relative humidity shall be
may be cut initially to the finished width.
recorded at frequent intervals to ensure that an accurate
8.4 This test method may not be suitable for some woven
determination of the average test humidity can be made.
geotextilesorgeogridsthatexhibitbreakingstrengthsinexcess
6.7.2 The test environment shall be maintained constant
of 100 kN/m (570 lbf/in.), due to clamping and equipment
throughoutthetest.Safetyprecautionsshouldbetakentoavoid
limitations.
personal contact during the test. The area should be isolated
adequately and fenced such that only the test operator has
9. Number of Tests
access to the test station.
9.1 Unless otherwise agreed upon, creep and creep rupture
tests shall be conducted at load levels as specified by the
7. Sampling
designer. Four load levels are recommended for characteriza-
7.1 Laboratory Sample—For the laboratory sample, take a
tion of the material. Loads shall be selected at intervals of
full-width swatch at least 1-m (40-in.) long in the machine
approximately 10 % of the maximum load per unit width as
direction from each roll in the lot sample. The sample may be
determined by applicable ASTM test methods.
taken from the end portion of a roll, provided there is no
9.1.1 For creep test, the loads should be 20, 30, 40, 50 and
evidence that it is different from other portions of the roll. See
60 %oftheultimatetensilestrengthofthesamplebeingtested,
Practice D4354.
unless otherwise agreed upon by the parties involved.
9.1.2 For creep rupture tests, the loads should be 50, 60, 70,
7.2 Test Specimens:
80, and 90 % of the ultimate tensile strength of the sample
7.2.1 Geotextiles and Geomembranes—For tests in the ma-
being tested, unless otherwise agreed upon by the parties
chine and cross-machine directions, respectively, take from
involved.
each sample the number of specimens as directed in 9.1. Take
the specimens from a diagonal on the sample, with no
NOTE 2—It is generally recognized that characterization involves
identification of the load levels at which there is no creep (no increase in
specimens closer than ⁄10 the width of the roll or 150 mm (6
strainwiththelogoftime),lowtomoderatecreep(linearincreaseinstrain
in.), whichever is smaller. For geomembranes, exercise care in
with the log of time), and high creep (exponential increase in strain with
selecting, cutting, and preparing the specimens to avoid nicks,
the log of time).
tears, scratches, folds, or other imperfections that are likely to
9.2 To evaluate design creep strains, it is recommended that
cause premature failure.
a minimum of two creep tests be performed for each test
NOTE 1—Nonreinforced geomembranes are extremely sensitive in this
temperature (that is, one at the design load and one at a load
regard.
that exceeds the design load, as specified by the designer).
7.2.2 Geogrids and Other Related Products—For tests in
9.3 To evaluate creep rupture, it is recom
...
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