ASTM D4632-91(2003)
(Test Method)Standard Test Method for Grab Breaking Load and Elongation of Geotextiles
Standard Test Method for Grab Breaking Load and Elongation of Geotextiles
SCOPE
1.1 This test method is an index test which provides a procedure for determining the breaking load (grab strength) and elongation (grab elongation) of geotextiles using the grab method. This test method is not suitable for knitted fabrics and alternate test methods should be used. While useful for quality control and acceptance testing for a specific fabric structure, the results can only be used comparatively between fabrics with very similar structures, because each different fabric structure performs in a unique and characteristic manner in this test. The grab test methods does not provide all the information needed for all design applications and other test methods should be used.
1.2 Procedures for measuring the breaking load and elongation by the grab method in both the dry and wet state are included; however, testing is normally done in the dry condition unless specified otherwise in an agreement or specification.
1.3 The values stated in SI units are to be regarded as standard. The values stated in inch-pound units are provided for information only.
1.4 This standard does not purport to address all of the safety problems, 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.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:D4632–91(Reapproved 2003)
Standard Test Method for
Grab Breaking Load and Elongation of Geotextiles
This standard is issued under the fixed designation D 4632; 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 (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope D 2905 Practice for Statements on Number of Specimens
for Textiles
1.1 This test method is an index test which provides a
D 4354 Practice for Sampling of Geosynthetics for Testing
procedure for determining the breaking load (grab strength)
D 4439 Terminology for Geotextiles
and elongation (grab elongation) of geotextiles using the grab
method. This test method is not suitable for knitted fabrics and
3. Terminology
alternate test methods should be used. While useful for quality
3.1 Definitions:
control and acceptance testing for a specific fabric structure,
3.1.1 atmosphere for testing geotextiles, n— air maintained
the results can only be used comparatively between fabrics
at a relative humidity of 65 6 5 % relative humidity and
with very similar structures, because each different fabric
temperature of 21 6 2°C (70 6 4°F).
structure performs in a unique and characteristic manner in this
3.1.2 breaking load, n—the maximum force applied to a
test.The grab test methods does not provide all the information
specimen in a tensile test carried to rupture.
needed for all design applications and other test methods
3.1.3 cross-machine direction, n—the direction in the plane
should be used.
of the fabric perpendicular to the direction of manufacture.
1.2 Procedures for measuring the breaking load and elon-
3.1.4 elongation at break, n—the elongation corresponding
gation by the grab method in both the dry and wet state are
to the breaking load, that is, the maximum load.
included; however, testing is normally done in the dry condi-
3.1.5 geotextile, n—any permeable textile material used
tion unless specified otherwise in an agreement or specifica-
with foundation, soil, rock, earth, or any other geotechnical
tion.
material, as an integral part of a man-made product, structure,
1.3 The values stated in SI units are to be regarded as
or system.
standard. The values stated in inch-pound units are provided
3.1.6 grab test, n—in fabric testing, a tension test in which
for information only.
only a part of the width of the specimen is gripped in the
1.4 This standard does not purport to address all of the
clamps.
safety concerns, if any, associated with its use. It is the
3.1.6.1 Discussion—For example, if the specimen width is
responsibility of the user of this standard to establish appro-
101.6 mm (4 in.) and the width of the jaw faces 25.4 mm (1
priate safety and health practices and determine the applica-
in.), the specimen is gripped centrally in the clamps.
bility of regulatory limitations prior to use.
3.1.7 machine direction, n—the direction in the plane of the
2. Referenced Documents fabric parallel to the direction of manufacture.
3.1.8 For definitions of other terms used in this test method,
2.1 ASTM Standards:
refer to Terminology D 123 or Terminology D 4439.
D76 Specification for Tensile Testing Machines for Tex-
tiles
4. Summary of Test Method
D 123 Terminology Relating to Textiles
2 4.1 A continually increasing load is applied longitudinally
D 461 Methods of Testing Felt
to the specimen and the test is carried to rupture.Values for the
D 1682 Test Methods for Breaking Load and Elongation of
2 breaking load and elongation of the test specimen are obtained
Textile Fabrics
from machine scales or dials, autographic recording charts, or
D 1776 Practice for Conditioning Textiles for Testing
interfaced computers.
5. Significance and Use
This test method is under the jurisdiction of ASTM Committee D35 on
5.1 The grab method is applicable whenever it is desired to
Geosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechani-
determine the “effective strength” of the fabric in use, that is,
cal Properties.
Current edition approved June 10, 2003. Published May 1991. Originally
published as D 4632–86. Last previous edition D 4632–86(1990).
2 3
Annual Book of ASTM Standards, Vol 07.01. Annual Book of ASTM Standards, Vol 04.13.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4632–91 (2003)
the strength of the material in a specific width, together with 7. Sampling and Selection
the additional strength contributed by adjacent material. There
7.1 Division into Lots and Lot Samples— Divide the mate-
isnosimplerelationshipbetweengrabtestsandstriptestssince
rial into lots and take a lot sample as directed in Practice
the amount of fabric assistance depends on the construction of
D 4354. Rolls of fabric are the primary sampling unit.
the fabric. It is useful as a quality control or acceptance test.
7.2 Laboratory Sample—Take for the laboratory sample a
5.2 The procedure in Test Method D 4632 for the determi-
swatch extending the width of the fabric and approximately 1
nation of grab strength of geotextiles may be used for accep-
m(39.37in.)alongtheselvagefromeachrollinthelotsample.
tance testing of commercial shipments, but caution is advised
The swatch may be taken from the end portion of a roll
since information about between-laboratory precision is in-
provided there is no evidence that it is distorted or different
complete. Comparative tests as directed in 5.2.1 are advisable.
from other portions of the roll. In cases of dispute, take a
5.2.1 In case of a dispute arising from differences in swatch that will exclude fabric from the outer wrap of the roll
or the inner wrap around the core.
reported test results when using the procedures in Test Method
D 4632 for acceptance testing of commercial shipments, the 7.3 Test Specimens—Cut the number of specimens from
purchaser and the manufacturer should conduct comparative each swatch in the laboratory sample determined as directed in
Section 8. Take no specimens nearer the selvage of fabric edge
tests to determine if there is a statistical bias between their
laboratories. Competent statistical assistance is recommended than ⁄20 of the fabric width or 150 mm (6 in.), whichever is the
smaller. Cut rectangular specimens 101.6 by 203.2 mm (4 by 8
for the investigation of bias. As a minimum, the two parties
should take a group of test specimens that are as homogeneous in.). Cut the specimens to be used for grab tests in the machine
direction with the longer dimension parallel to the machine
as possible and which are from a lot of material of the type in
direction and the specimens to be used for grab tests in the
question.Thetestspecimensshouldthenberandomlyassigned
cross-machine direction with the longer dimension parallel to
in equal numbers to each laboratory for testing. The average
the cross-machine direction. Locate each group of specimens
results from the two laboratories should be compared using the
along a diagonal line on the swatch so that each specimen will
appropriate Student’s t-test and an acceptable probability level
contain different warp ends and filling picks. Draw a line 37
chosen by the two parties before testing is begun. If a bias is
mm (1.5 in.) from the edge of the specimen running its full
found, either its cause must be found and corrected or the
length. For woven and reinforced nonwoven fabrics, this line
purchaser and the manufacturer must agree to interpret future
must be accurately parallel to the lengthwise yarns in the
test results in the light of the known bias.
specimen.
5.3 Mostgeotextilefabricscanbetestedbythistestmethod.
Some modification of clamping techniques may be necessary
8. Number of Specimens
for a given fabric, depending upon its structure. Special
adaptation may be necessary with strong fabrics, or fabrics 8.1 Unless otherwise agreed upon as when provided in an
made from glass fibers, to prevent them from slipping in the
applicable material specification, take a number of test speci-
clamps or being damaged as a result of being gripped in the mens per swatch in the laboratory sample such that the user
clamps,suchascushioningtheclamporboardingthespecimen may expect at the 95 % probability level that the test result is
within the clamp. nomorethan5 %abovethetrueaverageforeachswatchinthe
laboratory sample for each the machine and cross-machine
5.4 This test method is applicable for testing fabrics either
direction, respectively.
dryorwet.Itmaybeusedwithconstant-rate-of-traverse(CRT)
8.1.1 Reliable Estimate of v—When there is a reliable
or constant-rate-of-extension (CRE) type tension machines.
estimate of v based upon extensive past records for similar
However, there may be no overall correlation between the
materials tested in the user’s laboratory as directed in the
results obtained with the CRT machine and the CRE machine.
method, calculate the required number of specimens using Eq
Consequently, these two tension testers cannot be used inter-
1, as follows:
changeably. In case of controversy, the CRE machine shall
prevail.
n 5 ~tv/A! (1)
where:
6. Apparatus
n = number of test specimens (rounded upward to a whole
6.1 Tensile Testing Machine, of the constant-rate-of-
number),
extension (CRE) or constant-rate-of-traverse (CRT) type with
v = reliable estimate of the coefficient of variation of
autographic recorder conforming to the requirements of Speci-
individual observations on similar materials in the
ficationD76.
user’s laboratory under conditions of single-operator
6.2 Clamps, having all gripping surfaces parallel, flat, and
precision, %,
capable of preventing slipping of the specimen during a test. t = the value of Student’s t for one-sided limits (see Table
Each clamp shall have one jaw face measuring 25.4 by 50.8 1), a 95 % probability level, and the degrees of
mm (1 by 2 in.), with the longer di
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.