ASTM D4533/D4533M-15(2023)

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: D4533/D4533M − 15 (Reapproved 2023)
Standard Test Method for
Trapezoid Tearing Strength of Geotextiles
This standard is issued under the fixed designation D4533/D4533M; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope D123 Terminology Relating to Textiles
D1776/D1776M Practice for Conditioning and Testing Tex-
1.1 This test method is an index test used to measure the
tiles
force required to continue or propagate a tear in woven or
D2905 Practice for Statements on Number of Specimens for
nonwoven geotextiles by the trapezoid method. While useful
Textiles (Withdrawn 2008)
for quality control and acceptance testing, the trapezoid tear
D4354 Practice for Sampling of Geosynthetics and Rolled
test does not provide all the information needed for all design
Erosion Control Products (RECPs) for Testing
applications and other test methods should be used.
D4439 Terminology for Geosynthetics
1.2 This test method is applicable to most geotextiles that
E177 Practice for Use of the Terms Precision and Bias in
include woven fabrics, nonwoven fabrics, layered fabrics, knit
ASTM Test Methods
fabrics, and felts that are used for geotextile applications.
E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.3 The values stated in either SI units or inch-pound units
are to be regarded separately as standard. The values stated in
3. Terminology
each system are not necessarily exact equivalents; therefore, to
ensure conformance with the standard, each system shall be
3.1 Definitions:
used independently of the other, and values from the two
3.1.1 atmosphere for testing geotextiles, n—air maintained
systems shall not be combined.
at a relative humidity of 65 6 5 % and a temperature of
21 6 2 °C [70 6 4 °F].
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.1.2 geotextile, n—any permeable textile material used
responsibility of the user of this standard to establish appro-
with foundation, soil, rock, earth, or any other geotechnical
priate safety, health, and environmental practices and deter-
engineering related material as an integral part of a man-made
mine the applicability of regulatory limitations prior to use.
product, structure, or system.
1.5 This international standard was developed in accor-
3.1.3 tearing strength, n—the force required to either (1)
dance with internationally recognized principles on standard-
start, or (2) continue or propagate a tear in a fabric under
ization established in the Decision on Principles for the
specified conditions.
Development of International Standards, Guides and Recom-
3.1.3.1 Discussion—This test method uses the maximum
mendations issued by the World Trade Organization Technical
value of the tearing force as the tearing strength.
Barriers to Trade (TBT) Committee.
3.1.4 For definitions of other terms used in this test method,
2. Referenced Documents refer to Terminology D123 or Terminology D4439.
2.1 ASTM Standards:
4. Summary of Test Method
D76/D76M Specification for Tensile Testing Machines for
4.1 An outline of an isosceles trapezoid is marked on a
Textiles
rectangular specimen cut for the determination of tearing
strength (see Fig. 1), and the nonparallel sides of the trapezoid
This test method is under the jurisdiction of ASTM Committee D35 on
marked on the specimen are clamped in parallel jaws of a
Geosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechani-
tensile testing machine. The separation of the jaws is continu-
cal Properties.
Current edition approved June 15, 2023. Published June 2023. Originally ously increased so the tear propagates across the specimen. At
approved in 1991. Last previous edition approved in 2015 as D4533/D4533M – 15.
the same time, the force developed is recorded. The tearing
DOI: 10.1520/D4533_D4533M-15R23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4533/D4533M − 15 (2023)
strength is reached when the resistance to further reorientation
is greater than the force required to rupture one or more fibers
simultaneously.
5.2 The trapezoid tearing strength method is useful for
estimating the relative tear resistance of different fabrics or
different directions in the same fabric.
5.3 This test method may be used for acceptance testing of
commercial shipments; however, caution is advised since
information about between-laboratory precision is incomplete.
Comparative tests as directed in 5.3.1 may be advisable.
5.3.1 In case of a dispute arising from differences in
FIG. 1 Trapezoidal Template for Trapezoid Tearing Strength Test reported test results when using this test method for acceptance
testing of commercial shipments, the purchaser and the sup-
plier should conduct comparative tests to determine if there is
strength, which is the maximum value of the tearing force, is
a statistical bias between their laboratories. Competent statis-
obtained from the autographic force-extension curve (see Fig.
tical assistance is recommended for the investigation of bias.
2).
As a minimum, the two parties should take a group of test
specimens that are as homogeneous as possible and that are
5. Significance and Use
from a lot of material of the type in question. Test specimens
5.1 The trapezoid tear method is a test that produces tension
should then be randomly assigned in equal numbers to each
along a reasonably defined course such that the tear propagates
laboratory for testing. The average results from the two
across the width of the specimen. The trapezoid tearing
laboratories should be compared using the appropriate Stu-
strength for woven fabrics is determined primarily by the
dent’s t-test and an acceptable probability level chosen by the
properties of the yarns that are gripped in the clamps. In
two parties before testing is begun. If a bias is found, either its
nonwoven fabrics, because the individual fibers are more or
cause must be found and corrected or the purchaser and the
less randomly oriented and capable of some reorientation in the
supplier must agree to interpret future test results in the light of
direction of the applied load, the maximum trapezoid tearing
the known bias.
5.4 Most geotextile fabrics can be tested by this test method.
Some modification of clamping techniques may be necessary
for a given fabric, depending upon its structure. Special
adaptation may be necessary with strong fabrics, or fabrics
made from glass fibers, to prevent them from slipping in the
clamps or being damaged as a result of being gripped in the
clamps.
5.5 This test method may be used with constant-rate-of-
traverse (CRT) or constant-rate-of-extension (CRE) type ten-
sion machines. However, there may be no overall correlation
between the results obtained with the CRT machine and the
CRE machine. Consequently, these two tension testers cannot
be used interchangeably. In case of controversy, the CRE
machine shall prevail.
6. Apparatus
6.1 Tensile Testing Machine, of the constant-rate-of-
extension (CRE) or constant-rate-of-traverse (CRT) type with
autographic recorder conforming to the requirements of Speci-
fication D76/D76M.
6.2 Clamps, having all gripping surfaces parallel, flat, and
capable of preventing slipping of the specimen during a test,
and measuring 50.8 by no less than 76.2 mm [2 by no less than
3 in.], with the longer dimension perpendicular to the direction
of application of the load.
6.3 Trapezoidal Template, optional, having the dimensions
FIG. 2 Typical Tearing Force-Extension Curves for Individual Test
Specimens shown in Fig. 1.
D4533/D4533M − 15 (2023)
7. Sampling and Selection 7.3.3 Cutting Test Specimens—Take no specimens nearer
the selvage or edge of the fabric than 1/20th of the fabric width
7.1 Lot Sample—As a lot sample for acceptance testing, take
or 150 mm [6 in.], whichever is smaller. Cut rectangular
at random the number of rolls of fabric directed in an
specimens 76.2 by 201.6 mm [3 by 8 in.]. Cut the specimens to
applicable material specification or other agreement between
be used for the measurement of the tearing strength in the
the purchaser and the supplier, such as agreement to sample as
machine direction (or warp yarns), with the longer dimension
directed in Practice D4354. Consider rolls of fabric to be the
parallel to the machine direction (or warp yarns). Cut the
primary sampling units.
specimens to be used for the measurement of the tearing
NOTE 1—An adequate specification or other agreement between the
strength in the cross-machine direction (or filling yarns) with
purchaser and the supplier requires taking into account the variability
the longer dimension parallel to the cross-machine direction (or
between rolls of fabric and between specimens from a swatch from a roll
of fabric so as to provide a sampling plan with a meaningful producer’s filling yarns). Mark each specimen with an isosceles trapezoid
risk, consumer’s risk, acceptable quality level, and limiting quality level.
template (see Fig. 1). Make a preliminary cut 15.9 mm [0.625
7.2 Laboratory Sample—Take for the laboratory sample a in.] long at the center of the 25.4 mm [1 in.] edge, as shown
Fig. 1.
sample extending the width of the fabric and approximately
1 m [39.37 in.] along the selvage from each roll in the lot
NOTE 2—Cutting Test Specimen option: An option to cutting rectangu-
sample. The sample may be taken from the end portion of a
lar specimens is to use a six-sided die shown in Fig. 3 and Fig. 4. Such
roll, provided there is no evidence that it is distorted or
specimen facilitates placement alignment and alleviates the need to use a
different from other portions of the roll. In cases of dispute,
template and mark the specimen prior to testing.
take a sample that will exclude fabric from the outer wrap of
7.3.4 Number of Specimens—Unless otherwise agreed upon,
the roll or the inner wrap around the core.
as when provided in an applicable material specification, take
7.3 Test Specimens—Take test specimens as follows:
a number of test specimens per swatch in the laboratory sample
7.3.1 Woven Fabrics—Take the specimens to be used for the
such that the user may expect at the 95 % probability level that
measurement of the tearing strength of machine direction yarns
the test result is not more than 5.0 % of the average above the
from different sets of machine direction yarns. Take the
true average of the swatch when testing in the machine and
specimens to be used for the measurement of the tearing
cross-machine directions, respectively. Determine the number
strength of cross-machine direction yarns from different sets of
of specimens per swatch as follows:
cross-machine direction yarns and, when possible, from fabric
7.3.4.1 Reliable Estimate of v—When there is a reliable
woven from different bobbins.
estimate of v based upon extensive past records for similar
7.3.2 Nonwoven Fabrics—Take the specimens for the mea-
materials tested in the user’s laboratory as directed in the
surement of the machine direction tearing strength from
method, calculate the required number of specimens for the
different positions across the fabric. Take the specimens for the
machine and cross-machine directions as follows:
measurement of the cross-machine direction tearing strength
n 5 tv/A (1)
from different positions along the length of the fabric. ~ !
FIG. 3 Optional Trapezoidal Template for Trapezoid Tearing Strength Test
D4533/D4533M − 15 (2023)
FIG. 4 Typical and Optional Tearing Force Dies and Individual Test Specimens
TABLE 1 Values of Student’s t for One-Sided Limits
A
where:
and the 95 % Probability
n = number of test specimens (rounded upward to a whole
One- One- One-
df df df
Sided Sided Sided
number),
1 6.314 11 1.796 22 1.717
v = reliable estimate of the coefficient of variation of indi-
2 2.920 12 1.782 24 1.711
vidual observations on similar materials in the user’s
3 2.353 13 1.771 26 1.706
laboratory under conditions of single-operator
4 2.132 14 1.761 28 1.701
5 2.015 15 1.753 30 1.697
precision, %,
6 1.943 16 1.746 40 1.684
t = the value of Student’s t for one-sided limits (see Table
7 1.895 17 1.740 50 1.676
1), a 95 % probability level, and the degrees of freedom
8 1.860 18 1.734 60 1.671
9 1.833 19 1.729 120 1.658
associated with the estimate of v, and
10 1.812 20 1.725 1.645
A = 5.0 % of the average, the value of the allowable
A
Values in this table were calculated using Hewlett Packard HP 67/97 Users’
variation.
Library Programs 03848D, “One-Sided and Two-Sided Critical Values of Student’s
7.3.4.2 No Reliable Estimate of v—When there is no reliable
t” and 00350D, “Improved Normal and Inverse Distribution.” For values at other
than the 95 % probability level, see published tables of critical values of Student’s
estimate of v for the user’s laboratory, Eq 1 should not be used
t in any standard statistical text. Further use of this table is defined in Practice
directly. Instead, specify the fixed number (10) of specimens
D2905.
for the machine direction tests, and 10 specimens for the
cross-machine direction tests. The number of specimens is
calculated using v = 9.5 % of the average for both machine
8. Conditioning
direction and cross-machine direction tests. These values for v
are somewhat larger than usually found in practice. When a 8.1 Bring the specimens to moisture equilibrium in the
reliable estimate of v for the user’s laboratory becomes atmosphere for testing geotextiles (3.1). Equilibrium is consid-
available, Eq 1 will usually require fewer than the fixed ered to have been reached when the increase in mass of the
number of specimens. specimen, in successive weighings made at intervals of not less
D4533/D4533M − 15 (2023)
than 2 h, do
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