1、Designation: D6637 11D6637/D6637M 15Standard Test Method forDetermining Tensile Properties of Geogrids by the Single orMulti-Rib Tensile Method1This standard is issued under the fixed designation D6637;D6637/D6637M; the number immediately following the designation indicatesthe year of original adopt
2、ion or, in the 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.1. Scope1.1 This test method covers the determination of the tensile strength propert
3、ies of geogrids by subjecting strips of varying widthto tensile loading.1.2 Three alternative procedures are provided to determine the tensile strength, as follows:1.2.1 Method ATesting a single geogrid rib in tension (N or lbf).1.2.2 Method BTesting multiple geogrid ribs in tension (kN/m or lbf/ft)
4、.1.2.3 Method CTesting multiple layers of multiple geogrid ribs in tension (kN/m or lbf/ft).1.3 This test method is intended for quality control and conformance testing of geogrids.1.4 The values stated in either SI units or inch-pound units are to be regarded separately as the standard. The inch-po
5、und valuesstated in parentheses are provided for information only.each system may not be exact equivalents; therefore, each system shall beused independently of the other. Combining values from the two systems may result in non-conformance with the standard.1.5 This standard may involve hazardous ma
6、terials, operations, and equipment. This standard does not purport to address allof the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriatesafety and health practices and determine the applicability of regulatory limitation
7、s prior to use.2. Referenced Documents2.1 ASTM Standards:2D76D76/D76M Specification for Tensile Testing Machines for TextilesD123 Terminology Relating to TextilesD1909 Standard Tables of Commercial Moisture Regains and Commercial Allowances for Textile FibersD4354 Practice for Sampling of Geosynthet
8、ics and Rolled Erosion Control Products(RECPs) for TestingD4439 Terminology for GeosyntheticsD5262 Test Method for Evaluating the Unconfined Tension Creep and Creep Rupture Behavior of Geosynthetics3. Terminology3.1 Definitions:3.1.1 atmosphere for testing geosynthetics, nair maintained at a relativ
9、e humidity of 50 to 70 % and a temperature of 21 62C (7070 6 4F).4F.3.1.2 breaking force, (F), nthe force at failure.3.1.3 corresponding force, nsynonym for force at specified elongation.3.1.4 force at specified elongation, FASE, na force associated with a specific elongation on the force-elongation
10、 curve(synonym for corresponding force.)3.1.5 force-elongation curve, nin a tensile test, a graphical representation of the relationship between the magnitude of anexternally applied force and the change in length of the specimen in the direction of the applied force (synonym for stress-straincurve.
11、)1 This test method is under the jurisdiction ofASTM Committee D35 on Geosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechanical Properties.Current edition approved Oct. 1, 2011July 15, 2015. Published October 2011September 2015. Originally approved in 2001. Last previous ed
12、ition approved in 20102011as D663701(2010).D663711. DOI: 10.1520/D6637-11.10.1520/D6637_D6637M-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 Docum
13、ent Summary page on the ASTM website.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 re
14、commends 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 19428-2959. United States13.1.6 geogr
15、id, na geosynthetic formed by a regular network of integrally connected elements with apereturesapertures greaterthan 6.35 mm (14 in.)in. to allow interlocking with surrounding soil, rock, earth, and other surrounding materials to primarilyfunction as reinforcement. D52623.1.7 geosynthetic, na produ
16、ct manufactured from polymeric material used with soil, rock, earth, or other geotechnicalengineering related material as an integral part of a man made project, structure, or system.3.1.8 index test, na test procedure which may contain known bias, but which may be used to establish an order for a s
17、et ofspecimens with respect to the property of interest.3.1.9 integral, adjin geosynthetics, forming a necessary part of the whole; a constituent.3.1.10 junction, nthe point where geogrid ribs are interconnected to provide structure and dimensional stability.3.1.11 rib, nfor geogrids, the continuous
18、 elements of a geogrid which are interconnected to a node or junction.3.1.12 rupture, nfor geogrids, the breaking or tearing apart of ribs.3.1.13 tensile, adjcapable of tensions, or relating to tension of a material.3.1.14 tensile strength, (f), nfor geogrids the maximum resistance to deformation de
19、veloped for a specific material whensubjected to tension by an external force. Tensile strength of geogrids is the characteristic of a sample as distinct from a specimenand is expressed in force per unit width.3.1.15 tensile test, nfor geosynthetics, a test in which a material is stretched uniaxiall
20、y to determine the force-elongationcharacteristics, the breaking force, or the breaking elongation.3.1.16 tension, nthe force that produces a specified elongation.3.2 For definitions of other terms used in this test method, refer to Terminologies D123 and D4439.4. Summary of Test Method4.1 Method AI
21、n this method, a single, representative rib specimen of a geogrid is clamped and placed under a tensile forceusing a constant rate of extension testing machine. The tensile force required to fail (rupture) the specimen is recorded. Theultimate single rib tensile strength (N or lbf) is then determine
22、d based on the average of six single rib tensile tests.4.2 Method BA relatively wide specimen is gripped across its entire width in the clamps of a constant rate of extension typetensile testing machine operated at a prescribed rate of extension, applying a uniaxial load to the specimen until the sp
23、ecimenruptures. Tensile strength (kN/m or lbf/ft), elongation, and secant modulus of the test specimen can be calculated from machinescales, dials, recording charts, or an interfaced computer.4.3 Method CA relatively wide, multiple layered specimen is gripped across its entire width in the clamps of
24、 a constant rateof extension type tensile testing machine operated at a prescribed rate of extension, applying a uniaxial load to the specimen untilthe specimen ruptures. Tensile strength (kN/m or lbf/ft), elongation and secant modulus of the test specimen can be calculated frommachine scales, dials
25、 recording charts, or an interfaced computer.5. Significance and Use5.1 The determination of the tensile force-elongation values of geogrids provides index property values. This test method shallbe used for quality control and acceptance testing of commercial shipments of geogrids.5.2 In cases of di
26、spute arising from differences in reported test results when using this test method for acceptance testing ofcommercial shipments, the purchaser and supplier should conduct comparative tests to determine if there is a statistical biasbetween their laboratories. Competent statistical assistance is re
27、commended for the investigation of bias. As a minimum, the twoparties should take a group of test specimens which are as homogeneous as possible and which are from a lot of material of thetype in question. The test specimens should then be randomly assigned in equal numbers to each laboratory for te
28、sting. The averageresults from the two laboratories should be compared using Students t-test for unpaired data and an acceptable probability levelchosen by the two parties before the testing began. If a bias is found, either its cause must be found and corrected or the purchaserand supplier must agr
29、ee to interpret future test results in light of the known bias.5.3 All geogrids can be tested by any of these methods. Some modification of techniques may be necessary for a given geogriddepending upon its physical make-up. Special adaptations may be necessary with strong geogrids, multiple layered
30、geogrids, orgeogrids that tend to slip in the clamps or those which tend to be damaged by the clamps.6. Apparatus6.1 Testing ClampsThe clamps shall be sufficiently wide to grip the entire width of the specimen (as determined by the testmethod) and with appropriate clamping power to prevent slipping
31、or crushing (damage). For a given product, the same clamps shallbe used in testing methods A, B, and C prior to making any comparison between results.6.1.1 Size of Jaw FacesEach clamp shall have jaw faces measuring wider than the width of the specimen.D6637/D6637M 1526.2 Tensile Testing MachineA tes
32、ting machine of the constant rate of extension type as described in SpecificationD76D76/D76M shall be used. The machine shall be equipped with a device for recording the tensile force and the amount ofseparation of the grips. Both of these measuring systems shall be accurate to 6 1.0 % 61.0 % and, p
33、referably, shall be externalto the testing machine. The rate of separation shall be uniform and capable of adjustment within the range of the test.6.3 Distilled Water and Nonionic Wetting Agent, shall be used for wet specimens only.6.4 ExtensometerWhen required by the method, a device capable of mea
34、suring the distance between two reference points onthe specimen without any damage to the specimen or slippage, care being taken to ensure that the measurement represents the truemovement of the reference points. Examples of extensometers include mechanical, optical, infrared or electrical devices.7
35、. Sampling7.1 Lot SampleDivide the product into lots and take the lot sample as directed in Practice D4354.7.2 Laboratory SampleFor the laboratory sample, take a full roll width swatch long enough in the machine direction fromeach roll in the lot sample to ensure that the requirements in 8.1 can be
36、met. The sample may be taken from the end portion ofa roll provided there is no evidence it is distorted or different from other portions of the roll.8. Test Specimen8.1 The specimens shall consist of at least three (3) junctions or 300 mm in length (12 in.),12 in. in length, in order to establisha
37、minimum specimen length in the direction of the test (either the machine or cross-machine direction). test. The direction of thetest shall be defined as either the machine direction (MD), cross-machine direction (CMD), or a nominal skewed angle referencedfrom the machine direction, according to Fig.
38、 1, where MD and CMD are defined as 0 and 90, respectively.All specimens shouldbe free of surface defects, etc., not typical of the laboratory sample. Take no specimens nearer the selvage edge along the geogridthan 110 the width of the sample.NOTE 1If a comparison of one geogrid to another is to be
39、made the length of each specimen shall be the same (as similar as possibly) and agreedupon by all parties.8.2 Preparation:8.2.1 Method APrepare each finished specimen, as shown in Fig. 12, to contain at least one rib in the cross-test widebyintersecting rib (or set of ribs) crossing the test directi
40、on with at least three junctions (two apertures) long in the direction of thetesting, with the length dimension being designated and accurately cut parallel to the direction for which the tensile strength isbeing measured. See Note 2.NOTE 2In some applications, it may be necessary to perform tensile
41、 tests in more than one direction (for example, both the machine and thecross-machine direction). When testing a geogrid with ribs oriented in more than one direction, in all cases, the nominal rib direction of the tensile testspecimen(s) should be clearly noted per Fig. 1.8.2.2 Method BPrepare each
42、 finished specimen, as shown in Fig. 23, to be a minimum of 200 mm wide and contain five ribsin the cross-test direction wide by at least three junctions (two apertures) or 300 mm (12 in.)12 in. long in the direction of thetesting, with the length dimension being designated and accurately cut parall
43、el to the direction for which the tensile strength isbeing measured.8.2.3 Method CPrepare each finished specimen, as shown in Fig. 23, to be a minimum of 200 mm wide and contain five ribsin the cross-test direction wide by at least three junctions (two apertures) or 300 mm (12 in.)12 in. long in the
44、 direction of thetesting, with the length dimension being designated and accurately cut parallel to the direction for which the tensile strength isbeing measured. This must be repeated for each layer of geogrid included in the test.8.2.4 Within Test Methods A, B, and C, the outermost ribs are common
45、ly cut prior to testing to permit extra width of materialin the clamps to minimize slippage within the clamps. If this procedure causes nonuniform distribution of load to the gauge lengthFIG. 1 Specimen Orientation and Test DirectionD6637/D6637M 153area of the specimen, the same width of material sh
46、all be included in the clamps as will be tested in the gauge length area. In eithercase, the test results shall be based on the unit of width associated with the number of intact ribs.8.3 Number of Test Specimens:8.3.1 Unless otherwise agreed upon as when provided in an applicable material specifica
47、tion, take a number of test specimensper swatch in the laboratory sample such that the user may expect at the 95 % probability level that the test result is no more than5 % above the true average for each swatch in the laboratory sample for each required direction, see Note 2.NOTE 2In some applicati
48、ons, it may be necessary to perform tensile tests in both the machine and the cross-machine directions. In all cases, thedirection of the tensile test specimen(s) should be clearly noted.8.3.2 Reliable Estimate of vWhen there is a reliable estimate of v based upon extensive past records for similar
49、materialstested 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 materials in the users laboratory underconditions of single-operator precision, %,t = the value of Students t for one-sided limits, a 95 % probability level, and the degrees of freedom associated with theestimate of v,
