1、Designation: D4632/D4632M 08 (Reapproved 2013)2D4632/D4632M 15Standard Test Method forGrab Breaking Load and Elongation of Geotextiles1This standard is issued under the fixed designation D4632/D4632M; the number immediately following the designation indicates theyear of original adoption or, in the
2、case of revision, the year 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 NOTEUnits in
3、formation was editorially corrected in June 2013.2 NOTETable 1 was editorially inserted in Section 8.1.1 in March 2014.1. Scope1.1 This test method is an index test which provides a procedure for determining the breaking load (grab strength) andelongation (grab elongation) of geotextiles using the g
4、rab method. This test method is not suitable for knitted fabrics and alternatetest methods should be used. While useful for quality control and acceptance testing for a specific fabric structure, the results canonly be used comparatively between fabrics with very similar structures, because each dif
5、ferent fabric structure performs in aunique and characteristic manner in this test. The grab test methods does not provide all the information needed for all designapplications and other test methods should be used.1.2 Procedures for measuring the breaking load and elongation by the grab method in b
6、oth 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 either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be
7、 exact equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result in non-conformance with the standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilit
8、yof 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 ASTM Standards:2D76/D76M Specification for Tensile Testing Machines for TextilesD123 Terminology Relating to TextilesD17
9、76 Practice for Conditioning and Testing TextilesD2905 Practice for Statements on Number of Specimens for Textiles (Withdrawn 2008)3D4354 Practice for Sampling of Geosynthetics and Rolled Erosion Control Products(RECPs) for TestingD4439 Terminology for GeosyntheticsE177 Practice for Use of the Terms
10、 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 atmosphere for testing geotextiles, nair maintained at a relative humidity of 65 6 5 % relative humidity and temperatureof 21 6
11、 2C 70 6 4F.3.1.2 breaking load, nthe maximum force applied to a specimen in a tensile test carried to rupture.3.1.3 cross-machine direction, nthe direction in the plane of the fabric perpendicular to the direction of manufacture.1 This test method is under the jurisdiction ofASTM Committee D35 on G
12、eosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechanical Properties.Current edition approved May 1, 2013Jan. 1, 2015. Published June 2013February 2015. Originally approved in 1991. Last previous edition approved in 20082013 asD4632D4632/D4632M08. 08(2013)2. DOI: 10.1520/D46
13、32_D4632M-08R13E02.10.1520/D4632_D4632M-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approve
14、d version of this historical standard is referenced on www.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
15、all changes accurately, ASTM recommends that users consult 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-
16、2959. United States13.1.4 elongation at break, nthe elongation corresponding to the breaking load, that is, the maximum load.3.1.5 geotextile, nany permeable textile material used with foundation, soil, rock, earth, or any other geotechnical material,as an integral part of a man-made product, struct
17、ure, or system.3.1.6 grab test, nin fabric testing, a tension test in which only a part of the width of the specimen is gripped in the clamps.3.1.6.1 DiscussionFor example, if the specimen width is 101.6 mm 4 in. and the width of the jaw faces 25.4 mm 1 in., mm 1 in., the specimenis gripped centrall
18、y in the clamps.3.1.7 machine direction, nthe direction in the plane of the fabric parallel to the direction of manufacture.3.1.8 For definitions of other terms used in this test method, refer to Terminology D123 or Terminology D4439.4. Summary of Test Method4.1 A continually increasing load is appl
19、ied longitudinally to the specimen and the test is carried to rupture. Values for thebreaking load and elongation of the test specimen are obtained from machine scales or dials, autographic recording charts, orinterfaced computers.5. Significance and Use5.1 The grab method is applicable whenever it
20、is desired to determine the “effective strength” of the fabric in use, that is, thestrength of the material in a specific width, together with the additional strength contributed by adjacent material. There is nosimple relationship between grab tests and strip tests since the amount of fabric assist
21、ance depends on the construction of the fabric.It is useful as a quality control or acceptance test.5.2 The procedure in Test Method D4632/D4632M for the determination of grab strength of geotextiles may be used foracceptance testing of commercial shipments, but caution is advised since information
22、about between-laboratory precision isincomplete. Comparative tests as directed in 5.2.1 are advisable.5.2.1 In case of a dispute arising from differences in reported test results when using the procedures in Test MethodD4632/D4632M for acceptance testing of commercial shipments, the purchaser and th
23、e manufacturer should conduct comparativetests to determine if there is a statistical bias between their laboratories. Competent statistical assistance is recommended for theinvestigation of bias. As a minimum, the two parties should take a group of test specimens that are as homogeneous as possible
24、and which are from a lot of material of the type in question. The test specimens should then be randomly assigned in equal numbersto each laboratory for testing. The average results from the two laboratories should be compared using the appropriate Studentst-test and an acceptable probability level
25、chosen by the two parties before testing is begun. If a bias is found, either its cause mustbe found and corrected or the purchaser and the manufacturer must agree to interpret future test results in the light of the knownbias.5.3 Most geotextile fabrics can be tested by this test method. Some modif
26、ication of clamping techniques may be necessary fora given fabric, depending upon its structure. Special adaptation may be necessary with strong fabrics, or fabrics made from glassfibers, to prevent them from slipping in the clamps or being damaged as a result of being gripped in the clamps, such as
27、 cushioningthe clamp or boarding the specimen within the clamp.5.4 This test method is applicable for testing fabrics either dry or wet. It may be used with constant-rate-of-traverse (CRT) orconstant-rate-of-extension (CRE) type tension machines. However, there may be no overall correlation between
28、the resultsobtained 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 (CR
29、T) type with autographicrecorder conforming to the requirements of Specification D76/D76M.6.2 Clamps, having all gripping surfaces parallel, flat, and capable of preventing slipping of the specimen during a test. Eachclamp shall have one jaw face measuring 25.4 by 50.8 mm 1 by 2 in., with the longer
30、 dimension parallel to the direction ofapplication of the load. The other jaw face of each clamp shall be at least as large as its mate. Each jaw face shall be in line, bothwith respect to its mate in the same clamp and to the corresponding jaw of the other clamp.7. Sampling and Selection7.1 Divisio
31、n into Lots and Lot SamplesDivide the material into lots and take a lot sample as directed in Practice D4354. Rollsof fabric are the primary sampling unit.7.2 Laboratory SampleTake for the laboratory sample a swatch extending the width of the fabric and approximately 1 m 1 m39.37 in. along the selva
32、ge from each roll in the lot sample. The swatch may be taken from the end portion of a roll providedD4632/D4632M 152there is no evidence that it is distorted or different from other portions of the roll. In cases of dispute, take a swatch that will excludefabric from the outer wrap of the roll or th
33、e inner wrap around the core.7.3 Test SpecimensCut the number of specimens from each swatch in the laboratory sample determined as directed in Section8. Take no specimens nearer the selvage of fabric edge than 120 of the fabric width or 150 mm 6 in., whichever is the smaller.Cut rectangular specimen
34、s 101.6 by 203.2 mm 4 by 8 in. mm 4 by 8 in. Cut the specimens to be used for grab tests in themachine direction with the longer dimension parallel to the machine direction and the specimens to be used for grab tests in thecross-machine direction with the longer dimension parallel to the cross-machi
35、ne direction. Locate each group of specimens alonga diagonal line on the swatch so that each specimen will contain different warp ends and filling picks. Draw a line 37 mm 1.5in. 37 mm 1.5 in. from the edge of the specimen running its full length. For woven and reinforced nonwoven fabrics, this line
36、must be accurately parallel to the lengthwise yarns in the specimen.8. Number of Specimens8.1 Unless otherwise agreed upon as when provided in an applicable material specification, take a number of test specimens perswatch in the laboratory sample such that the user may expect at the 95 % probabilit
37、y level that the test result is no more than 5 %above the true average for each swatch in the laboratory sample for each the machine and cross-machine direction, respectively.8.1.1 Reliable Estimate of vWhen there is a reliable estimate of v based upon extensive past records for similar materialstes
38、ted in the users laboratory as directed in the method, calculate the required number of specimens using Eq 1, 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 mat
39、erials 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.8.1.
40、2 No Reliable Estimate of vWhen there is no reliable estimate of v for the users laboratory, Eq 1 should not be useddirectly. Instead, specify the fixed number of 10 specimens for the machine direction tests and 10 specimens for the cross-machinedirection tests. The number of specimens is calculated
41、 using v = 9.5 % of the average for both machine direction and cross-machinedirection. These values for v are somewhat larger than usually found in practice. When a reliable estimate of v for the userslaboratory becomes available, Eq 1 will usually require fewer than the fixed number of specimens.9.
42、 Conditioning9.1 Bring the specimens to moisture equilibrium in the atmosphere for testing geotextiles. Equilibrium is considered to havebeen reached when the increase in mass of the specimen in successive weighings made at intervals of not less than 2 h does notexceed 0.1 % of the mass of the speci
43、men. In general practice, the industry approaches equilibrium from the “as received” side.NOTE 1It is recognized that in practice geotextile materials are frequently not weighed to determine when moisture equilibrium has been reached.While such a procedure cannot be accepted in cases of dispute, it
44、may be sufficient in routine testing to expose the material to the standard atmospherefor testing 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,TABLE 1 Values of Students t for One-Sided Limitsand the 95 % Pr
45、obabilityAdf One-Sideddf One-Sideddf One-sideddf One-Sided df One-Sided df One-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 1.746 40 1.6847 1.895 17 1.740 50 1.6768 1.860 18 1.734 60 1.6719 1.833 19 1.729
46、 120 1.65810 1.812 20 1.725 1.645A Values in this table were calculated using Hewlett Packard HP 67/97 UsersLibrary Programs 03848D, “One-Sided and Two-Sided Critical Values ofStudentsStudents t t” ” and 00350D, “Improved Normal and Inverse Distribution.”For values at other than the 95 % probability
47、 level, see published tables of criticalvalues of Students t in any standard statistical text. Further use of this table isdefined in Practice D2905.D4632/D4632M 153certain fibers may exhibit slow moisture equalization rates from the “as received” wet side. When this is known, a preconditioning cycl
48、e, as describedin Practice D1776, may be agreed upon between contractual parties.9.2 Specimens to be tested in the wet condition shall be immersed in water maintained at a temperature of 21 6 2C 70 6 4F.The time of immersion must be sufficient to wet-out the specimens thoroughly, as indicated by no
49、significant change in strengthor elongation following a longer period of immersion, and at least 2 min. To obtain thorough wetting, it may be necessary oradvisable to add not more than 0.05 % of a nonionic neutral wetting agent to the water.10. Procedure10.1 Test the conditioned specimens in the standard atmosphere for testing in accordance with Section 9.10.2 Set the distance between the clamps at the start of the test at 75 6 1 mm 3 6 0.05 in. Select the load range of the testingmachine such that the maximum lo
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