1、Designation: D 4595 05Standard Test Method forTensile Properties of Geotextiles by the Wide-Width StripMethod1This standard is issued under the fixed designation D 4595; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 m
3、ethod. 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 direction
4、sfor 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
5、 measuring strip tensile properties is the width ofthe specimen. This width, by contrast, is greater than the lengthof the 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
6、 this test method minimizes the contraction effect of thosefabrics and 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 theresponsibilit
7、y 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 Documents2.1 ASTM Standards:2D76 Specification for Tensile Testing Machines for TextilesD 123 Terminology Relating to TextilesD 5
8、79 Specification for Greige Woven Glass FabricsD 1776 Practice for Conditioning Textiles for TestingD 2905 Practice for Statements on Number of Specimensfor TextilesD 4439 Terminology for Geosynthetics3. Terminology3.1 atmosphere for testing geotextiles, n.air maintained ata relative humidity of 65
9、6 5 % and a temperature of 21 6 2C(70 6 4F).3.2 breaking toughness, T, (FL1), 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 als
10、o work-to-break). Breaking tough-ness is calculated from work-to-break, gage 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.
11、the engineering applica-tion of geotechnics.3.5 geotechnics, n.the application 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 fiel
12、ds of soilmechanics, rock mechanics, and many of the engineeringaspects of 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
13、man-madeproject, structure, or system.3.7 initial tensile modulus, Ji, (FL1), Nm1, n.for geo-textiles, the ratio of the change in tensile force per unit widthto a change in strain (slope) of the initial portion of a force perunit width strain curve.1This test method is under the jurisdiction of ASTM
14、 Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechani-cal Properties.Current edition approved Aug. 15, 2005. Published September 2005. Originallyapproved in 1986. Last previous edition approved in 2001 as D459586(2001).2For referenced ASTM standards, visit
15、 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-295
16、9, United States.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 limit, n.the greatest stress whic
17、h 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 on a force per unitwidth strain
18、 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 limit. The point from the zero force
19、 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.for geotextiles, the maximumresi
20、stance 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 test, n.in textiles, a test in whic
21、h 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.) wide specimen is gripped in th
22、e 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 origin to the breaking point, and is
23、 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 terms used in this testmethod, refe
24、r to Terminology D 123 and Terminology D 4439.4. Summary of 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 a longitudinal force to the specime
25、n 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 of the wide-width stripforce elongat
26、ion properties of geotextiles provides designparameters for reinforcement type applications, for exampledesign of reinforced embankments over soft subgrades, rein-forced soil retaining walls, and reinforcement of slopes. Whenstrength is not necessarily a design consideration, an alterna-tive test me
27、thod may be used for acceptance testing. TestMethod D 4595 for the determination of the wide-width striptensile properties of geotextiles may be used for the acceptancetesting of commercial shipments of geotextiles but caution isadvised since information about between-laboratory precisionis incomple
28、te (Note 6). Comparative tests as directed in 5.1.1may be advisable.5.1.1 In cases of a dispute arising from differences inreported test results when using Test Method D 4595 foracceptance testing of commercial shipments, the purchaser andthe supplier should conduct comparative tests to determine if
29、there 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 material of the type in question. The
30、 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 before the testing began. If a bias is f
31、ound, 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 necessary for agiven geotextile dependin
32、g 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 modified asrequired at the discretion of the
33、 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 geotextileseither dry or wet. It is u
34、sed 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 this test method for determining design
35、 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 for some wovenfabrics used in geotext
36、ile applications that exhibit strengthsapproximately 100 kN/m or 600 lbf/in. due to clamping andequipment limitations. In those cases, 100-mm (4-in.) widthD4595052specimens may be substituted for 200-mm (8-in.) width speci-mens. On those fabrics, the contraction effect cited in 1.4 isminimal and, co
37、nsequently, 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, therecorder must have adequate pen response
38、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 Two basic clamp designs are shown in Fig. 1, Fig. 2,Fi
39、g. 3, and Fig. 4. These designs have been used in thelaboratory and have provided reproducible tensile strengths.These clamps may be modified to provide greater ease andspeed of clamping. In any event, caution must be taken toensure the type material and dimensions of the clamp areadequate for the u
40、sers expected fabric strength.6.2.2 Size of Jaw FacesEach clamp shall have jaw facesmeasuring wider than the width of the specimen, 200 mm (8in.), and a minimum of 50-mm (2-in.) length in the direction ofthe applied force.6.3 Area-Measuring DeviceUse an integrating accessoryto the tensile testing ma
41、chine or a planimeter.6.4 Distilled Water and Nonionic Wetting Agent, 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 sampl
42、ing for wide-width strip tensileproperties is generally defined in 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
43、parties, and what the basisfor the certification is, such as, historical data generated from materialmanufactured under the same conditions.7.2 Laboratory SampleFor the laboratory sample, take afull-width swatch approximately 1 m (40 in.) long in theFIG. 1 Wide Width Test ClampsD4595053machine direc
44、tion 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 other portions ofthe roll. In cases of dispute, take a sample that will excludefabric from the outer wrap of the roll or the inner wrap aroundth
45、e core.7.3 Test SpecimensFor tests in the machine direction andthe cross-machine direction, respectively, take from eachswatch in the laboratory sample the number of specimensdirected in Section 8. Take specimens at random from thelaboratory sample, with those for the measurement of themachine direc
46、tion tensile properties from different positionsacross the geotextile width, and the specimens for the mea-surement of the cross-machine direction tensile properties fromdifferent positions along the length of the geotextile. Take nospecimens nearer the selvage or edge of the geotextile than1/10 the
47、 width of the geotextile (see 8.2).8. Test Specimen Preparation8.1 Number of Specimens:8.1.1 Unless otherwise agreed upon, as when 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 re
48、sult is not more than 5.0 % ofthe average above or below the true average of the swatch foreach, the machine and cross-machine direction, respectively.Determine the number of specimens as follows:8.1.1.1 Reliable Estimate of vWhen there is a reliableestimate of v based upon extensive past records fo
49、r similarmaterials tested in the users laboratory as directed in themethod, calculate the required number of specimens using Eq1, as follows:n 5 tv/A!2(1)where:n = number of specimens (rounded upward to a wholenumber),v = reliable estimate of the coefficient of variation 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 th
