1、Designation: D4595 11Standard Test Method forTensile Properties of Geotextiles by the Wide-Width StripMethod1This standard is issued under the fixed designation D4595; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the measurement of tensileproperties of geotextiles using a wide-width strip specimentensile meth
3、od. This test method is applicable to most geotex-tiles that include woven fabrics, nonwoven fabrics, layeredfabrics, knit fabrics, and felts that are used for geotextileapplication.1.2 This test method covers the measurement of tensilestrength and elongation of geotextiles and includes directionsfo
4、r the calculation of initial modulus, offset modulus, secantmodulus, and breaking toughness.1.3 Procedures for measuring the tensile properties of bothconditioned and wet geotextiles by the wide-width stripmethod are included.1.4 The basic distinction between this test method and othermethods for me
5、asuring strip tensile properties is the width ofthe specimen. Some fabrics used in geotextile applicationshave a tendency to contract (neck down) under a force in thegage length area. The greater width of the specimen specifiedin this test method minimizes the contraction effect of thosefabrics and
6、provides a closer relationship to expected geotextilebehavior in the field and a standard comparison.1.5 This 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 hea
7、lth practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D76 Specification for Tensile Testing Machines for TextilesD123 Terminology Relating to TextilesD579 Specification for Greige Woven Glass FabricsD1776 Practice for Conditi
8、oning and Testing TextilesD2905 Practice for Statements on Number of Specimens forTextiles3D4439 Terminology for Geosynthetics3. Terminology3.1 atmosphere for testing geotextiles, n.air maintained ata relative humidity of 65 6 5 % and a temperature of 21 6 2C(70 6 4F).3.2 breaking toughness, T, (FL1
9、), Jm2, n.for geotextiles,the actual work-to-break per unit surface area of material.3.2.1 DiscussionBreaking toughness is proportional tothe area under the force elongation curve from the origin tothe breaking point (see also work-to-break). Breaking tough-ness is calculated from work-to-break, gag
10、e length, and widthof a specimen.3.3 corresponding force, Fc,n.the force associated with aspecific elongation on the force-per-unit-width strain curve.(Syn. load at specified elongation, LASE.)3.4 geotechnical engineering, n.the engineering applica-tion of geotechnics.3.5 geotechnics, n.the applicat
11、ion of scientific methodsand engineering principles to the acquisition, interpretation,and use of knowledge of materials of the earths crust to thesolution of engineering problems.3.5.1 DiscussionGeotechnics embraces the fields of soilmechanics, rock mechanics, and many of the engineeringaspects of
12、geology, geophysics, hydrology, and related sci-ences.3.6 geotextile, n.any permeable textile material used withfoundation, soil, rock, earth, or any other geotechnical engi-neering related material, as an integral part of a man-madeproject, structure, or system.3.7 initial tensile modulus, Ji, (FL1
13、), Nm1, n.for geo-textiles, the ratio of the change in tensile force per unit width1This 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 Oct. 1, 2011. Published Marc
14、h 2009. Originallyapproved in 1986. Last previous edition approved in 2009 as D4595 09. DOI:10.1520/D4595-11.2For 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 sta
15、ndards Document Summary page onthe ASTM website.3Withdrawn. The last 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.to a change in strain (slope) of the initi
16、al portion of a force perunit width strain curve.3.8 offset tensile modulus, Jo, (FL1), Nm1, n.for geo-textiles, the ratio of the change in force per unit width to achange in strain (slope) below the proportional limit point andabove the tangent point on the force elongation curve.3.9 proportional l
17、imit, n.the greatest stress which a ma-terial is capable of sustaining without any deviation fromproportionality of stress to strain (Hookes law).3.10 secant tensile modulus, Jsec(FL1), Nm1, n.forgeotextiles, the ratio of change in force per unit width to achange in strain (slope) between two points
18、 on a force per unitwidth strain curve.3.11 tangent point, n.for geotextiles, the first point of theforce elongation curve at which a major decrease in slopeoccurs.3.11.1 DiscussionThe tangent point is determined bydrawing a tangent line passing through the zero axis and theproportional elastic limi
19、t. The point from the zero force axisthat the force elongation curve first touches that tangent lineis the tangent point.3.12 tensile modulus, J, (FL1), Nm1, n.for geotextiles,the ratio of the change in tensile force per unit width to acorresponding change in strain (slope).3.13 tensile strength, n.
20、for geotextiles, the maximumresistance to deformation developed for a specific materialwhen subjected to tension by an external force.3.13.1 DiscussionTensile strength of geotextiles is thecharacteristic of a sample as distinct from a specimen and isexpressed in force per unit width.3.14 tensile tes
21、t, n.in textiles, a test in which a textilematerial is stretched in one direction to determine theforce elongation characteristics, the breaking force, or thebreaking elongation.3.15 wide-width strip tensile test, n.for geotextiles,auniaxial tensile test in which the entire width of a 200-mm(8.0-in.
22、) wide specimen is gripped in the clamps and the gagelength is 100 mm (4.0 in.).3.16 work-to-break, W, (LF), n.in tensile testing, the totalenergy required to rupture a specimen.3.16.1 DiscussionFor geotextiles, work-to-break is pro-portional to the area under the force elongation curve fromthe orig
23、in to the breaking point, and is commonly expressed injoules (inch-pound-force).3.17 yield point, n.the first point of the force elongationcurve above the proportional (linear) section at which anincrease in elongation occurs without a corresponding increasein force.3.18 For terminology of other ter
24、ms used in this testmethod, refer to Terminology D123 and Terminology D4439.4. Summary of Test Method4.1 A relatively wide specimen is gripped across its entirewidth in the clamps of a constant rate of extension (CRE) typetensile testing machine operated at a prescribed rate of exten-sion, applying
25、a longitudinal force to the specimen until thespecimen ruptures. Tensile strength, elongation, initial andsecant modulus, and breaking toughness of the test specimencan be calculated from machine scales, dials, recording charts,or an interfaced computer.5. Significance and Use5.1 The determination o
26、f the wide-width strip force elon-gation properties of geotextiles provides design parameters forreinforcement type applications, for example design of rein-forced embankments over soft subgrades, reinforced soil re-taining walls, and reinforcement of slopes. When strength isnot necessarily a design
27、 consideration, an alternative testmethod may be used for acceptance testing. Test MethodD4595 for the determination of the wide-width strip tensileproperties of geotextiles may be used for the acceptance testingof commercial shipments of geotextiles but caution is advisedsince information about bet
28、ween-laboratory precision is in-complete (Note 6). Comparative tests as directed in 5.1.1 maybe advisable.5.1.1 In cases of a dispute arising from differences inreported test results when using Test Method D4595 foracceptance testing of commercial shipments, the purchaser andthe supplier should cond
29、uct comparative tests to determine ifthere is a statistical bias between their laboratories. Competentstatistical assistance is recommended for the investigation ofbias.As a minimum, the two parties should take a group of testspecimens which are as homogeneous as possible and whichare from a lot of
30、material of the type in question. The testspecimens should then be randomly assigned in equal numbersto each laboratory for testing. The average results from the twolaboratories should be compared using Students t-test forunpaired data and an acceptable probability level chosen by thetwo parties bef
31、ore the testing began. 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.5.2 Most geotextiles can be tested by this test method. Somemodification of clamping techniques may be nec
32、essary for agiven geotextile depending upon its structure. Special clamp-ing adaptions may be necessary with strong geotextiles orgeotextiles made from glass fibers to prevent them fromslipping in the clamps or being damaged as a result of beinggripped in the clamps. Specimen clamping may be modifie
33、d asrequired at the discretion of the individual laboratory providinga representative tensile strength is obtained. In any event, theprocedure described in Section 10 of this test method forobtaining wide-width strip tensile strength must be maintained.5.3 This test method is applicable for testing
34、geotextileseither dry or wet. It is used with a constant rate of extensiontype tension apparatus.5.4 The use of tensile strength test methods that restrict theclamped width dimension to 50 mm (2 in.) or less, such as theravel, cut strip, and grab test procedures, have been found lesssuitable than th
35、is test method for determining design strengthparameters for some geotextiles. This is particularly the casefor nonwoven geotextiles. The wide-width strip technique hasbeen explored by the industry and is recommended in thesecases for geotextile applications.5.4.1 This test method may not be suited
36、for some wovenfabrics used in geotextile applications that exhibit strengthsapproximately 100 kN/m or 600 lbf/in. due to clamping andD4595 112equipment limitations. In those cases, 100-mm (4-in.) widthspecimens may be substituted for 200-mm (8-in.) width speci-mens. On those fabrics, the contraction
37、 effect cited in 1.4 isminimal and, consequently, the standard comparison can con-tinue to be made.6. Apparatus and Reagents6.1 Tensile Testing MachineA constant rate of extension(CRE) type of testing machine described in Specification D76shall be used. When using the CRE type tensile tester, therec
38、order must have adequate pen response to properly recordthe forceelongation curve as specified in Specification D76.6.2 ClampsThe clamps shall be sufficiently wide to gripthe entire width of the sample and with appropriate clampingpower to prevent slipping or crushing (damage).6.2.1 There are severa
39、l types of clamp designs available.Three basic clamp design examples are shown in Fig. 1, Fig. 2,and Fig. 3. These designs have been used in the laboratory andhave provided reproducible tensile strengths. These clampsmay be modified to provide greater ease and speed of clamp-ing. In any event, cauti
40、on must be taken to ensure the typematerial and dimensions of the clamp are adequate for theusers expected fabric strength.Additional guidance is given inAppendix X56.2.2 Size of Jaw FacesEach clamp shall have jaw facesmeasuring wider than the width of the specimen, 200 mm (8in.), and a minimum of 5
41、0-mm (2-in.) length in the direction ofthe applied force.6.3 External extensometers or other external means ofmeasurement are encouraged for all tests where modulus is tobe measured. In this case, the distance between the moving feetof the extensometer determines the gage length for use inelongation
42、 calculations and not test speed. Examples of contactand noncontact extensometers are shown in Fig. 5, Fig. 6, andFig. 7. Please see Note 6 and Appendix X5.6.4 Area-Measuring DeviceUse an integrating accessoryto the tensile testing machine or a planimeter.6.5 Distilled Water and Nonionic Wetting Age
43、nt, for wetspecimens only.7. Sampling7.1 Lot SampleFor the lot sample, take rolls of geotextilesas directed in an applicable material specification, or as agreedupon between the purchaser and the supplier.NOTE 1The extent of the sampling for wide-width strip tensileproperties is generally defined in
44、 an applicable order or contract. Amongthe options available to the purchaser and the supplier is for the purchaserto accept certification by the manufacturer that the material in questionmeets the requirements agreed upon by the two parties, and what the basisfor the certification is, such as, hist
45、orical data generated from materialmanufactured under the same conditions.7.2 Laboratory SampleFor the laboratory sample, take afull-width swatch from each roll in the lot sample. The samplemay be taken from the end portion of a roll provided there isno evidence it is distorted or different from oth
46、er portions ofthe roll. In cases of dispute, take a sample that will excludefabric from the outer wrap of the roll or the inner wrap aroundthe core.7.3 Test SpecimensFor tests in the machine direction andthe cross-machine direction, respectively, take from eachswatch in the laboratory sample the num
47、ber of specimensdirected in Section 8. Take specimens at random from thelaboratory sample, with those for the measurement of themachine direction tensile properties from different positionsacross the geotextile width, and the specimens for the mea-surement of the cross-machine direction tensile prop
48、erties fromdifferent positions along the length of the geotextile. Take nospecimens nearer the selvage or edge of the geotextile than1/10 the width of the geotextile (see 8.2).FIG. 1 Wedge ClampsD4595 1138. Test Specimen Preparation8.1 Number of Specimens:8.1.1 Unless otherwise agreed upon, as when
49、specified in anapplicable material specification, take a number of specimensper fabric swatch such that the user may expect at the 95 %probability level that the test result is not more than 5.0 % ofthe average above or below the true average of the swatch forFIG. 2 Inserts for Wedge ClampsFIG. 3 Roller ClampsFIG. 4 End View of Composite of Clamp, Insert, and Threaded RodD4595 114each, the machine and cross-machine direction, respectively.Determine the number of specimens as follows:8.1.1.1 Reliable Estimate of vWhe
