ASTM D7406-07(2012)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: D7406 − 07 (Reapproved 2012)
Standard Test Method for
Time-Dependent (Creep) Deformation Under Constant
Pressure for Geosynthetic Drainage Products
This standard is issued under the fixed designation D7406; 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 D5199 Test Method for Measuring the Nominal Thickness
of Geosynthetics
1.1 This test method is used to determine the unconfined
D5261 Test Method for Measuring Mass per Unit Area of
compressive creep characteristics of drainage geotextiles,
Geotextiles
geocomposites, geonets, or any other geosynthetic associated
D5262 Test Method for Evaluating the Unconfined Tension
with drainage at a constant temperature, when subjected to a
Creep and Creep Rupture Behavior of Geosynthetics
constant compressive stress.
D6364 Test Method for Determining Short-Term Compres-
1.2 This test method is intended for use as an unconfined
sion Behavior of Geosynthetics
compressive performance creep test only. For a detailed
2.2 EN Standard:
procedureonhowtoestablishanindextestseetheENstandard
EN 1897
1897.Forperformancetests,thespecimenshallbesubjectedto
the site-specific liquid and/or the site-specific stress (normal
3. Terminology
and potentially shear stress).
3.1 For definitions related to geosynthetics, see Terminol-
NOTE 1—Results achieved from unconfined compressive performance
ogy D4439.
creep may differ from testing performed under confined conditions.
3.2 Fordefinitionsrelatedtocreep,seeTestMethodsD2990
1.3 Because of the changing nature of the geosynthetic
and D5262.
industry, and the wide variety of products already available,
3.3 Definitions:
this particular test method may have to be slightly modified for
3.3.1 compressive creep, n—time-dependent deformation or
unconfined compression creep testing of some products.
compressive strain of a material subjected to a constant
1.4 The values given in SI units are to be considered as the
compressive stress.
standard. The values given in parentheses are for information
3.3.2 compressive creep rupture, n—failure by collapse of a
only.
material subjected to a constant compressive stress.
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Summary of Test Method
responsibility of the user of this standard to establish appro-
4.1 In this performance test method, a geosynthetic drain-
priate safety and health practices and determine the applica-
age product is subjected to a sustained normal and potentially
bility of regulatory limitations prior to use.
shear stresses. Deformations of the specimen are recorded at
designated time intervals, and a graph is drawn.
2. Referenced Documents
4.2 The specimen may be immersed in a site-specific water
2.1 ASTM Standards:
or permeant, to simulate actual field conditions.
D2990 Test Methods for Tensile, Compressive, and Flexural
Creep and Creep-Rupture of Plastics
4.3 For long-term testing it is recommended that the test be
D4439 Terminology for Geosynthetics
run for at least 1000 h. Dwell times up to 10000 hr have been
used, if that longer time data is required.
4.4 Creep load (normal as well as potentially shear) should
This test method is under the jurisdiction of ASTM Committee D35 on
Geosynthetics and is the direct responsibility of Subcommittee D35.02 on Endur- reflect the actual field conditions
ance Properties.
4.5 The test will be conducted at site specific temperatures.
Current edition approved July 1, 2012. Published July 2012. DOI: 10.1520/
D7406-07R12.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 5. Significance and Use
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.1 The performance characteristics of a drainage geosyn-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. thetic are directly related to the integrity under compressive
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7406 − 07 (2012)
loading. If the product is sensitive to compressive creep, its 150 mm (6.0 by 6.0 in.), but can have size of 300 by 300 mm
flow capacity could be greatly reduced or even shut off (12.0 by 12.0 in.) or larger to assure the test setup remains
completely. unconfined.
5.2 The creep sensitivity of a candidate geosynthetic can be 6.3 Base Platen— The base platen shall be rigid enough to
tested at field-simulated normal stress and potentially shear resist bending and, in turn, support a uniform normal stress.A
stresses. thick steel plate is advisable.The base platen shall be placed in
the specimen container to support the tested specimen. When
5.3 This test method does not evaluate the effect of creep of
shear stress is applied it is necessary to avoid slippage of the
a geotextile filter or adjacent membrane.
tested specimen with the base platen (rough surfaces on the
5.4 Compression creep as it relates to reduction in flow
platen are recommended). Ideally the base platen will be larger
capacity of a geosynthetic drainage product is manufacturer
than the specimen size to support the specimen during draping
and product specific. For example, a 10% reduction in original
and flexing under the stress assembly.
thickness of a geonet made by manufacturer A does not
6.4 Loading Platen— The loading platen shall be rigid
necessarily equal the same reduction in flow capacity as a 10%
enough to resist bending and, in turn, apply a uniform normal
reduction in thickness of the same or another type of geonet
stress. When shear stress is applied it is necessary to avoid
made by manufacturer B.
slippage of the tested specimen with the loading platen (rough
5.5 This creep data has is merit directly to the end user,
surfaces on the platen are recommended). The loading platen
because it can be easily interpreted to result into a reduction
shall be slightly larger than the specimen to provide even
factor for creep . The Reduction factor can then be used to
compression during the entire duration of the test. In addition
derive an allowable flow rate .
the loading platen will be attached to the stress assembly in
such a way that no stress is placed on the specimen until the
6. Apparatus
commencement of the test and the weight of which is included
6.1 Overall System— Fig. 1 shows a compression creep test in the measurement of the applied stress when appropriate for
the loading system used.
setup. It consists of a loading platen, a normal stress assembly,
potentially a shear load assembly (not shown in Fig. 1),
6.5 Digital Gages—Atleast3digitalgagesaccurateto0.01
potentially a specimen container, and three digital gages (one
mm (0.0005 in.) shall be used to measure specimen deforma-
shown in Fig. 1).
tion for the normal stress assembly. Alternatively, any device
that can measure deformations to an accuracy of 0.01 mm
6.2 Specimen Container— The specimen container shall
have a flat, rigid surface on which the base platen is placed. (0.0005 in.) may be substituted for a digital gage (for example,
The container shall be deep enough to allow the test specimen a linear variable differential transformer (LVDT)). If a shear
to be completely immersed during testing. The container shall stress assembly is used 1 digital gages shall be used to measure
be large enough to hold a minimum specimen size of 150 by that deformation.
6.6 Normal Stress and Potentially Shear Stress Assembly —
The compressive stress may be applied mechanically,
pneumatically, or hydraulically. The loading device, however,
shall be capable of applying the full magnitude of test stress in
Giroud, J.-P., Zhao, A. and Richardson, G. N. (2000), “Effect of Thickness
one controlled step (with no significant impact). Some systems
Reduction on Geosynthetic Hydraulic Transmissivity,” Geosynthetics International,
may use dead weights to apply stress.At high stress levels, the
Vol. 7, Nos. 4-6, pp. 433-452.
GRI GC-8 standard (2001), “Standard guide for determination of the allowable
flow rate of a drainage geocomposite”
FIG. 1 Creep Apparatus Cross Section
D7406 − 07 (2012)
FIG. 2 Typical Geocomposite Creep Response
magnitude of the weight required may make it diffic
...