ASTM D4533-91(1996)

Standard Test Method for Trapezoid Tearing Strength of Geotextiles

SCOPE
1.1 This test method is an index test used to measure the force required to continue or propagate a tear in woven or non-woven geotextiles by the trapezoid method. While useful for quality control and acceptance testing, the trapezoid tear test does not provide all the information needed for all design applications and other test methods should be used.  
1.2 This test method is applicable to most geotextiles that include woven fabrics, nonwoven fabrics, layered fabrics, knit fabrics, and felts that are used for geotextile applications.  
1.3 The values stated in SI units are to be regarded as the standard.  
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

• Status: Historical
• Publication Date: 09-Jun-1996
• ICS: 59.080.70 - Geotextiles
• Technical Committee: D35 - Geosynthetics
• Drafting Committee: D35.01 - Mechanical Properties

Relations

• Replaced By: ASTM D4533-04 - Standard Test Method for Trapezoid Tearing Strength of Geotextiles
• Effective Date: 01-Nov-2004
• Referred By: ASTM D6389-17 - Standard Practice for Tests to Evaluate the Chemical Resistance of Geotextiles to Liquids
• Effective Date: 10-Jun-1996
• Referred By: ASTM F2970-22 - Standard Practice for Design, Manufacture, Installation, Operation, Maintenance, Inspection and Major Modification of Trampoline Courts
• Effective Date: 10-Jun-1996
• Referred By: ASTM D6685-01(2015) - Standard Guide for the Selection of Test Methods for Fabrics Used for Fabric Formed Concrete (FFC) (Withdrawn 2024)
• Effective Date: 10-Jun-1996
• Referred By: ASTM D8102-17 - Standard Practice for Manufacturing Quality Control of Geotextiles
• Effective Date: 10-Jun-1996
• Referred By: ASTM D4759-11(2018)e1 - Standard Practice for Determining the Specification Conformance of Geosynthetics
• Effective Date: 10-Jun-1996

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:D4533–91(Reapproved 1996)
Standard Test Method for
Trapezoid Tearing Strength of Geotextiles
This standard is issued under the fixed designation D 4533; 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.
1. Scope 3.1.3 tearing strength, n—the force required to either (1)
start, or (2) continue or propagate a tear in a fabric under
1.1 This test method is an index test used to measure the
specified conditions.
force required to continue or propagate a tear in woven or
3.1.3.1 Discussion—This test method uses the maximum
non-woven geotextiles by the trapezoid method. While useful
value of the tearing force as the tearing strength.
for quality control and acceptance testing, the trapezoid tear
3.1.4 For definitions of other terms used in this test method,
test does not provide all the information needed for all design
refer to Terminology D 123 or Terminology D 4439.
applications and other test methods should be used.
1.2 This test method is applicable to most geotextiles that
4. Summary of Test Method
include woven fabrics, nonwoven fabrics, layered fabrics, knit
4.1 An outline of an isosceles trapezoid is marked on a
fabrics, and felts that are used for geotextile applications.
rectangular specimen cut for the determination of tearing
1.3 The values stated in SI units are to be regarded as the
strength (see Fig. 1), and the nonparallel sides of the trapezoid
standard.
marked on the specimen are clamped in parallel jaws of a
1.4 This standard does not purport to address all of the
tensile testing machine. The separation of the jaws is continu-
safety concerns, if any, associated with its use. It is the
ously increased so the tear propagates across the specimen. At
responsibility of the user of this standard to establish appro-
the same time, the force developed is recorded. The tearing
priate safety and health practices and determine the applica-
strength, which is the maximum value of the tearing force, is
bility of regulatory limitations prior to use.
obtainedfromtheautographicforce–extensioncurve(seeFig.
2. Referenced Documents 2).
2.1 ASTM Standards:
5. Significance and Use
D 76 Specification for Tensile Testing Machines for Tex-
5.1 The trapezoid tear method is a test that produces tension
tiles
2 along a reasonably defined course such that the tear propagates
D 123 Terminology Relating to Textiles
across the width of the specimen. The trapezoid tearing
D 1776 Practice for Conditioning Textiles for Testing
strength for woven fabrics is determined primarily by the
D 2905 Practice for Statements on Number of Specimens
properties of the yarns that are gripped in the clamps. In
for Textiles
3 nonwoven fabrics, because the individual fibers are more or
D 4354 Practice for Sampling of Geosynthetics for Testing
lessrandomlyorientedandcapableofsomereorientationinthe
D 4439 Terminology for Relating to Geosynthetics
direction of the applied load, the maximum trapezoid tearing
3. Terminology strength is reached when the resistance to further reorientation
is greater than the force required to rupture one or more fibers
3.1 Definitions:
simultaneously.
3.1.1 atmosphere for testing geotextiles, n—air maintained
5.2 The trapezoid tearing strength method is useful for
at a relative humidity of 65 6 5 % and a temperature of 21 6
estimating the relative tear resistance of different fabrics or
2°C (70 6 4°F).
different directions in the same fabric.
3.1.2 geotextile, n—any permeable textile material used
5.3 This test method may be used for acceptance testing of
with foundation, soil, rock, earth, or any other geotechnical
commercial shipments; however, caution is advised since
engineering related material as an integral part of a man-made
information about between-laboratory precision is incomplete.
product, structure, or system.
Comparative tests as directed in 5.3.1 may be advisable.
5.3.1 In case of a dispute arising from differences in
This test method is under the jurisdiction of ASTM Committee D-35 on
reported test results when using this test method for acceptance
Geosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechani-
testing of commercial shipments, the purchaser and the sup-
cal Properties.
plier should conduct comparative tests to determine if there is
Current edition approved Aug. 15, 1991. Published December 1991.
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.
D4533–91 (1996)
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.
FIG. 1 Trapezoidal Template for Trapezoid Tearing Strength Test
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 D 76.
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
shown in Fig. 1.
7. Sampling and Selection
7.1 Lot Sample—As a lot sample for acceptance testing,
take at random the number of rolls of fabric directed in an
applicable material specification or other agreement between
the purchaser and the supplier, such as agreement to sample as
directed in Practice D 4354. Consider rolls of fabric to be the
primary sampling units.
NOTE 1—An adequate specification or other agreement between the
purchaser and the supplier requires taking into account the variability
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
risk, consumer’s risk, acceptable quality level, and limiting quality level.
7.2 Laboratory Sample—Take for the laboratory sample a
sample extending the width of the fabric and approximately 1
m(39.37in.)alongtheselvagefromeachrollinthelotsample.
FIG. 2 Typical Tearing Force – Extension Curves for Individual
The sample may be taken from the end portion of a roll,
Test Specimens
provided there is no evidence that it is distorted or different
from other portions of the roll. In cases of dispute, take a
a statistical bias between their laboratories. Competent statis-
sample that will exclude fabric from the outer wrap of the roll
tical assistance is recommended for the investigation of bias. or the inner wrap around the core.
As a minimum, the two parties should take a group of test 7.3 Test Specimens—Take test specimens as follows:
specimens that are as homogeneous as possible and that are 7.3.1 Woven Fabrics—Take the specimens to be used for
from a lot of material of the type in question. Test specimens the measurement of the tearing strength of machine direction
should then be randomly assigned in equal numbers to each yarns from different sets of machine direction yarns. Take the
laboratory for testing. The average results from the two specimens to be used for the measurement of the tearing
laboratories should be compared using the appropriate Stu- strength of cross-machine direction yarns from different sets of
dent’s t-test and an acceptable probability level chosen by the cross-machine direction yarns and, when possible, from fabric
two parties before testing is begun. If a bias is found, either its woven from different bobbins.
cause must be found and corrected or the purchaser and the 7.3.2 Nonwoven Fabrics—Take the specimens for the mea-
supplier must agree to interpret future test results in the light of surement of the machine direction tearing strength from
the known bias. different positions across the fabric.Take the specimens for the
5.4 Mostgeotextilefabricscanbetestedbythistestmethod. measurement of the cross-machine direction tearing strength
Some modification of clamping techniques may be necessary from different positions along the length of the fabric.
D4533–91 (19
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