1、Designation: D4533 11D4533/D4533M 15Standard Test Method forTrapezoid Tearing Strength of Geotextiles1This standard is issued under the fixed designation D4533;D4533/D4533M; the number immediately following the designation indicatesthe year of original adoption or, in the case of revision, the year
2、of last revision. A number in parentheses indicates the year of lastreapproval. 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. Scope1.1 This test method is an index
3、test used to measure the force required to continue or propagate a tear in woven or non-wovengeotextiles by the trapezoid method. While useful for quality control and acceptance testing, the trapezoid tear test does not provideall the information needed for all design applications and other test met
4、hods 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 either SI units or inch-pound units are to be regarded as the standard.
5、No other units of measurementare included in this separately as standard. The values stated in each system may not be exact equivalents; therefore, each systemshall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.1.4 This stan
6、dard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 AST
7、M Standards:2D76D76/D76M Specification for Tensile Testing Machines for TextilesD123 Terminology Relating to TextilesD1776 Practice for Conditioning and Testing TextilesD2905 Practice for Statements on Number of Specimens for Textiles (Withdrawn 2008)3D4354 Practice for Sampling of Geosynthetics and
8、 Rolled Erosion Control Products(RECPs) for TestingD4439 Terminology for GeosyntheticsE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method3. Terminology3.1 Definitions:3.1.1 atmosph
9、ere for testing geotextiles, nair maintained at a relative humidity of 65 6 5 % and a temperature of 21 6 2C(70 6 4F).21 6 2C 70 6 4F.3.1.2 geotextile, nany permeable textile material used with foundation, soil, rock, earth, or any other geotechnical engineeringrelated material as an integral part o
10、f a man-made product, structure, or system.3.1.3 tearing strength, nthe force required to either (1) start, or (2) continue or propagate a tear in a fabric under specifiedconditions.3.1.3.1 Discussion1 This test method is under the jurisdiction ofASTM Committee D35 on Geosynthetics and is the direct
11、 responsibility of Subcommittee D35.01 on Mechanical Properties.Current edition approved June 1, 2011Jan. 1, 2015. Published July 2011February 2015. Originally approved in 1991. Last previous edition approved in 20002011 as D4533 04(2009).11. DOI: 10.1520/D4533-11.10.1520/D4533_D4533M-15.2 For refer
12、encedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. ForAnnual Book ofASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on w
13、ww.astm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consu
14、lt prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1This test method uses the maximum va
15、lue of the tearing force as the tearing strength.3.1.4 For definitions of other terms used in this test method, refer to Terminology D123 or Terminology D4439.4. Summary of Test Method4.1 An outline of an isosceles trapezoid is marked on a rectangular specimen cut for the determination of tearing st
16、rength (seeFig. 1), and the nonparallel sides of the trapezoid marked on the specimen are clamped in parallel jaws of a tensile testing machine.The separation of the jaws is continuously increased so the tear propagates across the specimen. At the same time, the forcedeveloped is recorded. The teari
17、ng strength, which is the maximum value of the tearing force, is obtained from the autographicforce extension curve (see Fig. 2).5. Significance and Use5.1 The trapezoid tear method is a test that produces tension along a reasonably defined course such that the tear propagatesacross the width of the
18、 specimen. The trapezoid tearing strength for woven fabrics is determined primarily by the properties of theyarns that are gripped in the clamps. In nonwoven fabrics, because the individual fibers are more or less randomly oriented andcapable of some reorientation in the direction of the applied loa
19、d, the maximum trapezoid tearing strength is reached when theresistance 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 dif
20、ferentdirections in the same fabric.5.3 This test method may be used for acceptance testing of commercial shipments; however, caution is advised sinceinformation 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 arisi
21、ng from differences in reported test results when using this test method for acceptance testing ofcommercial shipments, the purchaser and the supplier should conduct comparative tests to determine if there is a statistical biasbetween their laboratories. Competent statistical assistance is recommend
22、ed for the investigation of bias. As a minimum, the twoparties should take a group of test specimens that are as homogeneous as possible and that are from a lot of material of the typein question. Test specimens should then be randomly assigned in equal numbers to each laboratory for testing. The av
23、erage resultsfrom the two laboratories should be compared using the appropriate Students t-test and an acceptable probability level chosen bythe two parties before testing is begun. If a bias is found, either its cause must be found and corrected or the purchaser and thesupplier must agree to interp
24、ret future test results in the light of the known bias.5.4 Most geotextile fabrics can be tested by this test method. Some modification of clamping techniques may be necessary fora given fabric, depending upon its structure. Special adaptation may be necessary with strong fabrics, or fabrics made fr
25、om glassfibers, 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 tensionmachines. However, there may be no overall correlation between
26、 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. Apparatus6.1 Tensile Testing Machine, of the constant-rate-of-extension (CRE) or constant-rate-of-traverse (
27、CRT) type with autographicrecorder conforming to the requirements of Specification D76D76/D76M.6.2 Clamps, having all gripping surfaces parallel, flat, and capable of preventing slipping of the specimen during a test, andmeasuring 50.8 by no less than 76.2 mm (22 by no less than 3 in.),in., with the
28、 longer dimension perpendicular to the directionof application of the load.FIG. 1 Trapezoidal Template for Trapezoid Tearing Strength TestD4533/D4533M 1526.3 Trapezoidal Template, optional, having the dimensions shown in Fig. 1.7. Sampling and Selection7.1 Lot SampleAs a lot sample for acceptance te
29、sting, take at random the number of rolls of fabric directed in an applicablematerial specification or other agreement between the purchaser and the supplier, such as agreement to sample as directed inPractice D4354. Consider rolls of fabric to be the primary sampling units.NOTE 1An adequate specifi
30、cation or other agreement between the purchaser and the supplier requires taking into account the variability between rollsof fabric and between specimens from a swatch from a roll of fabric so as to provide a sampling plan with a meaningful producers risk, consumers risk,acceptable quality level, a
31、nd limiting quality level.7.2 Laboratory SampleTake for the laboratory sample a sample extending the width of the fabric and approximately 1 m(39.37 in.)39.37 in. along the selvage from each roll in the lot sample. The sample may be taken from the end portion of a roll,provided there is no evidence
32、that it is distorted or different from other portions of the roll. In cases of dispute, take a sample thatwill exclude fabric from the outer wrap of the roll or the inner wrap around the core.7.3 Test SpecimensTake test specimens as follows:7.3.1 Woven FabricsTake the specimens to be used for the me
33、asurement of the tearing strength of machine direction yarnsfrom different sets of machine direction yarns. Take the specimens to be used for the measurement of the tearing strength ofcross-machine direction yarns from different sets of cross-machine direction yarns and, when possible, from fabric w
34、oven fromdifferent bobbins.7.3.2 Nonwoven FabricsTake the specimens for the measurement of the machine direction tearing strength from differentpositions across the fabric. Take the specimens for the measurement of the cross-machine direction tearing strength from differentpositions along the length
35、 of the fabric.7.3.3 Cutting Test SpecimensTake no specimens nearer the selvage or edge of the fabric than 1/20th of the fabric width or,150 mm (6 in.)6 in. whichever is smaller. Cut rectangular specimens 76.2 by 201.6 mm (33 by 8 in.).in. Cut the specimensto be used for the measurement of the teari
36、ng strength in the machine direction (or warp yarns), with the longer dimension parallelto the machine direction (or warp yarns). Cut the specimens to be used for the measurement of the tearing strength in thecross-machine direction (or filling yarns) with the longer dimension parallel to the cross-
37、machine direction (or filling yarns). Markeach specimen with an isosceles trapezoid template (see Fig. 1). Make a preliminary cut 15.9 mm (0.625 in.)0.625 in. long atthe center of the 25.4 mm (1 in.)1 in. edge, as shown Fig. 1.FIG. 2 Typical Tearing Force Extension Curves for Individual Test Specime
38、nsD4533/D4533M 153NOTE 2Cutting Test Specimen option:An option to cutting rectangular specimens is to use a six sided die shown in Fig. 3 and Fig. 4. Such specimenfacilitates placement alignment and alleviates the need to use a template and mark the specimen prior to testing.7.3.4 Number of Specimen
39、sUnless otherwise agreed upon, as when provided in an applicable material specification, take anumber of test specimens per swatch in the laboratory sample such that the user may expect at the 95 % probability level that thetest result is not more than 5.0 % of the average above the true average of
40、the swatch when testing in the machine andcross-machine directions, respectively. Determine the number of specimens per swatch as follows:7.3.4.1 Reliable Estimate of vWhen there is a reliable estimate of v based upon extensive past records for similar materialstested in the users laboratory as dire
41、cted in the method, calculate the required number of specimens for the machine andcross-machine directions as follows:n 5tv/A!2 (1)where:n = number of test specimens (rounded upward to a whole number),v = reliable estimate of the coefficient of variation of individual observations on similar materia
42、ls in the users laboratory underconditions of single-operator precision, %,t = the value of Students t for one-sided limits (see Table 1), a 95 % probability level, and the degrees of freedom associatedwith the estimate of v, andA = 5.0 % of the average, the value of the allowable variation.where:n
43、= number of test specimens (rounded upward to a whole number),v = reliable estimate of the coefficient of variation of individual observations on similar materials in the users laboratory underconditions of single-operator precision, %,t = the value of Students t for one-sided limits (see Table 1),
44、a 95 % probability level, and the degrees of freedom associatedwith the estimate of v, andA = 5.0 % of the average, the value of the allowable variation.7.3.4.2 No Reliable Estimate of vWhen there is no reliable estimate of v for the users laboratory, Eq 1 should not be useddirectly. Instead, specif
45、y the fixed number (10) of specimens for the machine direction tests, and 10 specimens for thecross-machine direction tests. The number of specimens is calculated using v = 9.5 % of the average for both machine directionand cross-machine direction tests. These values for v are somewhat larger than u
46、sually found in practice. When a reliable estimateof v for the users laboratory becomes available, Eq 1 will usually require fewer than the fixed number of specimens.Table 1FIG. 3 Optional Trapezoidal Template for Trapezoid Tearing Strength TestD4533/D4533M 1548. Conditioning8.1 Bring the specimens
47、to moisture equilibrium in the atmosphere for testing geotextiles (3.1). Equilibrium is considered tohave been reached when the increase in mass of the specimen, in successive weighings made at intervals of not less than 2 h, doesnot exceed 0.1 % of the mass of the specimen. In general practice, the
48、 industry approaches equilibrium from the “as received” side.NOTE 3It is recognized that in practice, geotextile materials are frequently not weighed to determine when moisture equilibrium has been reached.While such a method cannot be accepted in cases of dispute, it may be sufficient in routine te
49、sting to expose the material to the standard atmosphere fortesting for a reasonable period of time before the specimens are tested. A time of at least 24 h has been found acceptable in most cases. However, certainfibers may exhibit slow moisture equilization rates from the “as received” wet side. When this is known, a preconditioning cycle, as described in PracticeD1776, may be agreed upon by the contractural parties for routine testing.8.2 Specimens to be tested in the wet condition shall be immersed in water maintained at a te
