1、Designation: D4533 11Standard Test Method forTrapezoid Tearing Strength of Geotextiles1This standard is issued under the fixed designation D4533; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number i
2、n parentheses indicates the year of last reapproval. Asuperscript epsilon () 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. Scope1.1 This test method is an index test used to measure theforce req
3、uired to continue or propagate a tear in woven ornon-woven geotextiles by the trapezoid method. While usefulfor quality control and acceptance testing, the trapezoid teartest does not provide all the information needed for all designapplications and other test methods should be used.1.2 This test me
4、thod is applicable to most geotextiles thatinclude woven fabrics, nonwoven fabrics, layered fabrics, knitfabrics, and felts that are used for geotextile applications.1.3 The values stated in SI units are to be regarded as thestandard. No other units of measurement are included in thisstandard.1.4 Th
5、is standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documen
6、ts2.1 ASTM Standards:2D76 Specification for Tensile Testing Machines for TextilesD123 Terminology Relating to TextilesD1776 Practice for Conditioning and Testing TextilesD2905 Practice for Statements on Number of Specimens forTextiles3D4354 Practice for Sampling of Geosynthetics for TestingD4439 Ter
7、minology for Geosynthetics3. Terminology3.1 Definitions:3.1.1 atmosphere for testing geotextiles, nair maintainedat a relative humidity of 65 6 5 % and a temperature of 21 62C (70 6 4F).3.1.2 geotextile, nany permeable textile material usedwith foundation, soil, rock, earth, or any other geotechnica
8、lengineering related material as an integral part of a man-madeproduct, 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 underspecified conditions.3.1.3.1 DiscussionThis test method uses the maximumvalue of the teari
9、ng 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 arectangular specimen cut for the determination of tearingstrength (see Fig. 1)
10、, and the nonparallel sides of the trapezoidmarked on the specimen are clamped in parallel jaws of atensile testing machine. The separation of the jaws is continu-ously increased so the tear propagates across the specimen. Atthe same time, the force developed is recorded. The tearingstrength, which
11、is the maximum value of the tearing force, isobtained from the autographic force extension curve (see Fig.2).5. Significance and Use5.1 The trapezoid tear method is a test that produces tensionalong a reasonably defined course such that the tear propagatesacross the width of the specimen. The trapez
12、oid tearingstrength for woven fabrics is determined primarily by theproperties of the yarns that are gripped in the clamps. Innonwoven fabrics, because the individual fibers are more orless randomly oriented and capable of some reorientation in thedirection of the applied load, the maximum trapezoid
13、 tearingstrength is reached when the resistance to further reorientationis greater than the force required to rupture one or more fiberssimultaneously.5.2 The trapezoid tearing strength method is useful forestimating the relative tear resistance of different fabrics ordifferent directions in the sam
14、e fabric.1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechani-cal Properties.Current edition approved June 1, 2011. Published July 2011. Originally approvedin 1991. Last previous edition approved in 2000
15、as D4533 04(2009). DOI:10.1520/D4533-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last
16、approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.3 This test method may be used for acceptance testing ofcommercial shipments; however, caution is advised sin
17、ceinformation 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 inreported test results when using this test method for acceptancetesting of commercial shipments, the purchaser and the sup-plie
18、r should conduct comparative tests to determine if there isa statistical bias between their laboratories. Competent statis-tical assistance is recommended for the investigation of bias.As a minimum, the two parties should take a group of testspecimens that are as homogeneous as possible and that are
19、from a lot of material of the type in question. Test specimensshould then be randomly assigned in equal numbers to eachlaboratory for testing. The average results from the twolaboratories should be compared using the appropriate Stu-dents t-test and an acceptable probability level chosen by thetwo p
20、arties before testing is begun. If a bias is found, either itscause must be found and corrected or the purchaser and thesupplier must agree to interpret future test results in the light ofthe known bias.5.4 Most geotextile fabrics can be tested by this test method.Some modification of clamping techn
21、iques may be necessaryfor a given fabric, depending upon its structure. Specialadaptation may be necessary with strong fabrics, or fabricsmade from glass fibers, to prevent them from slipping in theclamps or being damaged as a result of being gripped in theclamps.5.5 This test method may be used wit
22、h constant-rate-of-traverse (CRT) or constant-rate-of-extension (CRE) type ten-sion machines. However, there may be no overall correlationbetween the results obtained with the CRT machine and theCRE machine. Consequently, these two tension testers cannotbe used interchangeably. In case of controvers
23、y, the CREmachine shall prevail.6. Apparatus6.1 Tensile Testing Machine, of the constant-rate-of-extension (CRE) or constant-rate-of-traverse (CRT) type withautographic recorder conforming to the requirements of Speci-fication D76.6.2 Clamps, having all gripping surfaces parallel, flat, andcapable o
24、f preventing slipping of the specimen during a test,and measuring 50.8 by no less than 76.2 mm (2 by no less than3 in.), with the longer dimension perpendicular to the directionof application of the load.6.3 Trapezoidal Template, optional, having the dimensionsshown in Fig. 1.7. Sampling and Selecti
25、on7.1 Lot SampleAs a lot sample for acceptance testing,take at random the number of rolls of fabric directed in anapplicable material specification or other agreement betweenthe purchaser and the supplier, such as agreement to sample asdirected in Practice D4354. Consider rolls of fabric to be thepr
26、imary sampling units.NOTE 1An adequate specification or other agreement between thepurchaser and the supplier requires taking into account the variabilitybetween rolls of fabric and between specimens from a swatch from a rollof fabric so as to provide a sampling plan with a meaningful producersrisk,
27、 consumers risk, acceptable quality level, and limiting quality level.7.2 Laboratory SampleTake for the laboratory sample asample extending the width of the fabric and approximately1 m (39.37 in.) along the selvage from each roll in the lotsample. The sample may be taken from the end portion of arol
28、l, provided there is no evidence that it is distorted ordifferent from other portions of the roll. In cases of dispute,take a sample that will exclude fabric from the outer wrap ofthe roll or the inner wrap around the core.7.3 Test SpecimensTake test specimens as follows:7.3.1 Woven FabricsTake the
29、specimens to be used forthe measurement of the tearing strength of machine directionyarns from different sets of machine direction yarns. Take thespecimens to be used for the measurement of the tearingFIG. 1 Trapezoidal Template for Trapezoid Tearing Strength TestFIG. 2 Typical Tearing Force Extensi
30、on Curves for IndividualTest SpecimensD4533 112strength of cross-machine direction yarns from different sets ofcross-machine direction yarns and, when possible, from fabricwoven from different bobbins.7.3.2 Nonwoven FabricsTake the specimens for the mea-surement of the machine direction tearing stre
31、ngth fromdifferent positions across the fabric. Take the specimens for themeasurement of the cross-machine direction tearing strengthfrom different positions along the length of the fabric.7.3.3 Cutting Test SpecimensTake no specimens nearerthe selvage or edge of the fabric than 1/20th of the fabric
32、 widthor, 150 mm (6 in.) whichever is smaller. Cut rectangularspecimens 76.2 by 201.6 mm (3 by 8 in.). Cut the specimens tobe used for the measurement of the tearing strength in themachine direction (or warp yarns), with the longer dimensionparallel to the machine direction (or warp yarns). Cut thes
33、pecimens to be used for the measurement of the tearingstrength in the cross-machine direction (or filling yarns) withthe longer dimension parallel to the cross-machine direction (orfilling yarns). Mark each specimen with an isosceles trapezoidtemplate (see Fig. 1). Make a preliminary cut 15.9 mm (0.
34、625in.) long at the center of the 25.4 mm (1 in.) edge, as shownFig. 1.NOTE 2Cutting Test Specimen option: An option to cutting rectangu-lar specimens is to use a six sided die shown in Fig. 3 and Fig. 4. Suchspecimen facilitates placement alignment and alleviates the need to use atemplate and mark
35、the specimen prior to testing.7.3.4 Number of SpecimensUnless otherwise agreedupon, as when provided in an applicable material specification,take a number of test specimens per swatch in the laboratorysample such that the user may expect at the 95 % probabilitylevel that the test result is not more
36、than 5.0 % of the averageabove the true average of the swatch when testing in themachine and cross-machine directions, respectively. Determinethe number of specimens per swatch as follows:7.3.4.1 Reliable Estimate of vWhen there is a reliableestimate of v based upon extensive past records for simila
37、rmaterials tested in the users laboratory as directed in themethod, calculate the required number of specimens for themachine and cross-machine directions as follows:n 5 tv/A!2(1)where:n = number of test specimens (rounded upward to a wholenumber),v = reliable estimate of the coefficient of variatio
38、n ofindividual observations on similar materials in theusers laboratory under conditions of single-operatorprecision, %,t = the value of Students t for one-sided limits (see Table1), a 95 % probability level, and the degrees offreedom associated with the estimate of v, andA = 5.0 % of the average, t
39、he value of the allowablevariation.7.3.4.2 No Reliable Estimate of vWhen there is no reli-able estimate of v for the users laboratory, Eq 1 should not beused directly. Instead, specify the fixed number (10) ofspecimens for the machine direction tests, and 10 specimensfor the cross-machine direction
40、tests. The number of specimensis calculated using v = 9.5 % of the average for both machinedirection and cross-machine direction tests. These values for vare somewhat larger than usually found in practice. When areliable estimate of v for the users laboratory becomesavailable, Eq 1 will usually requ
41、ire fewer than the fixednumber of specimens. Table 1FIG. 3 Optional Trapezoidal Template for Trapezoid Tearing Strength TestD4533 1138. Conditioning8.1 Bring the specimens to moisture equilibrium in theatmosphere for testing geotextiles (3.1). Equilibrium is consid-ered to have been reached when the
42、 increase in mass of thespecimen, in successive weighings made at intervals of not lessthan 2 h, does not exceed 0.1 % of the mass of the specimen.In general practice, the industry approaches equilibrium fromthe “as received” side.NOTE 3It is recognized that in practice, geotextile materials arefreq
43、uently not weighed to determine when moisture equilibrium has beenreached. While such a method cannot be accepted in cases of dispute, itmay be sufficient in routine testing to expose the material to the standardatmosphere for testing for a reasonable period of time before thespecimens are tested. A
44、 time of at least 24 h has been found acceptable inmost cases. However, certain fibers may exhibit slow moisture equiliza-tion rates from the “as received” wet side. When this is known, apreconditioning cycle, as described in Practice D1776, may be agreedupon by the contractural parties for routine
45、testing.8.2 Specimens to be tested in the wet condition shall beimmersed in water maintained at a temperature of 21 6 2C(706 4F). The time of immersion must be sufficient to wet-outthe specimens thoroughly; this is indicated by no significantchange in strength or elongation following a longer period
46、 ofimmersion, and at least 2 min. To obtain thorough wetting, itmay be necessary, and advisable, to add not more than 0.05 %of a nonionic neutral wetting agent to the water.9. Procedure9.1 Test the conditioned specimens in the standard atmo-sphere for testing as defined in 3.1.FIG. 4 Typical and Opt
47、ional Tearing Force Dies and Individual Test SpecimensTABLE 1 Values of Students t for One-Sided Limits and the95 % ProbabilityAdfOne-SideddfOne-SideddfOne-Sided1 6.314 11 1.796 22 1.7172 2.920 12 1.782 24 1.7113 2.353 13 1.771 26 1.7064 2.132 14 1.761 28 1.7015 2.015 15 1.753 30 1.6976 1.943 16 1.7
48、46 40 1.6847 1.895 17 1.740 50 1.6768 1.860 18 1.734 60 1.6719 1.833 19 1.729 120 1.65810 1.812 20 1.725 1.645AValues in this table were calculated using Hewlett Packard HP 67/97 UsersLibrary Programs 03848D, “One-Sided and Two-Sided Critical Values of Studentst” and 00350D,“ Improved Normal and Inv
49、erse Distribution”. For values at otherthan the 95 % probability level, see published tables of critical values of Studentst in any standard statistical text. Further use of this table is defined in PracticeD2905.D4533 1149.2 Test the thoroughly wet specimen in the normal machineset-up within 2 min. after removal from the water.9.3 Set the distance between the clamps at the start of thetest at 25 6 1mm(16 0.05 in.). The upper clamp should besupported by a free swivel or universal joint which will allowthe clamp to rotate in the plane of the f
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