ASTM D4885-2001(2018) Standard Test Method for Determining Performance Strength of Geomembranes by the Wide Strip Tensile Method《用宽带拉伸法测定土工膜性能强度的标准试验方法》.pdf

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1、Designation: D4885 01 (Reapproved 2018)Standard Test Method forDetermining Performance Strength of Geomembranes bythe Wide Strip Tensile Method1This standard is issued under the fixed designation D4885; the number immediately following the designation indicates the year oforiginal adoption or, in th

2、e case of revision, the year of last 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 determination of the perfor-mance strength of synthetic ge

3、omembranes by subjecting widestrips of material to tensile loading.1.2 This test method covers the measurement of tensilestrength and elongation of geomembranes and includes direc-tions for calculating initial modulus, offset modulus, secantmodulus, and breaking toughness.1.3 The basic distinctions

4、between this test method andother methods measuring tensile strength of geomembranes arethe width of the specimens tested and the speed of appliedforce. The greater width of the specimens specified in this testmethod minimizes the contraction edge effect (necking) whichoccurs in many geosynthetics a

5、nd provides a closer relation-ship to actual material behavior in service. The slower speed ofapplied strain also provides a closer relationship to actualmaterial behavior in service.1.4 As a performance test, this method will be used rela-tively infrequently, and to test large lots of material. Thi

6、s testmethod is not intended for routine quality control testing ofgeomembranes.1.5 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with it

7、s use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized princ

8、iples on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D76/D76M Specification for Tensi

9、le Testing Machines forTextilesD123 Terminology Relating to TextilesD751 Test Methods for Coated FabricsD882 Test Method for Tensile Properties of Thin PlasticSheetingD1593 Specification for Nonrigid Vinyl Chloride PlasticFilm and SheetingD1909 Standard Tables of Commercial Moisture Regainsand Comme

10、rcial Allowances for Textile FibersD4354 Practice for Sampling of Geosynthetics and RolledErosion Control Products (RECPs) for TestingD4439 Terminology for Geosynthetics3. Terminology3.1 Definitions:3.1.1 atmosphere for testing geomembranes, nair main-tained at a relative humidity of 50 to 70 % and

11、a temperatureof 21 6 2 C (70 6 4 F).3.1.1.1 DiscussionWithin the range of 50 to 70 % relativehumidity, moisture content is not expected to affect the tensileproperties of geomembrane materials. In addition, geotextilestandard test methods restrict the range of relative humidity to65 6 5 %, while geo

12、membrane standard test methods restrictthe range of relative humidity to 55 6 5 %. The restrictedrange in this test method is made broader to reduce the need fortesting laboratories to change laboratory conditions, and con-sidering the lack of expected effect of moisture on geomem-branes. The user s

13、hould consult Table D1909 to resolvequestions regarding moisture regains of textile fibers, espe-cially if the user is testing a new or unknown material.3.1.2 breaking force, (F), J, nthe force at failure.3.1.3 breaking toughness, T, (FL1), Jm2, nforgeosynthetics, the actual work per unit volume of

14、a materialcorresponding to the breaking force.1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.10 on Geomem-branes.Current edition approved May 1, 2018. Published May 2018. Originallyapproved in 1988. Last previous

15、 edition approved in 2011 as D4885 01 (2011).DOI: 10.1520/D4885-01R18.2For 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

16、 website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment

17、 of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.1.3.1 DiscussionBreaking toughness is proportional tothe area under the force-elongation curve from the origin to thebreaking point (see also, work-to-break).

18、 Breaking toughness iscalculated from work-to-break and width of a specimen. Ingeomembranes, breaking toughness is often expressed as forceper unit width of material in inch-pound values. In othermaterials, breaking toughness is often expressed as work perunit mass of material.3.1.4 corresponding fo

19、rce, nsynonym for force at speci-fied elongation.3.1.5 elastic limit, nin mechanics, the stress intensity atwhich stress and deformation of a material subjected to anincreasing force cease to be proportional; the limit of stresswithin which a material will return to its original size and shapewhen t

20、he force is removed, and hence, not a permanent set.3.1.6 failure, nan arbitrary point beyond which a materialceases to be functionally capable of its intended use.3.1.6.1 DiscussionIn wide strip tensile testing ofgeosynthetics, failure occurs either at the rupture point or at theyield point in the

21、force-elongation curve, whichever occursfirst. For reinforced geomembranes, failure occurs at rupture ofthe reinforcing fabric. For nonreinforced geomembranes thatexhibit a yield point, such as polyethylene materials, failureoccurs at the yield point. Even though the geomembranecontinues to elongate

22、, the force-elongation relationship hasbeen irreversibly altered. For nonreinforced geomembranesthat do not exhibit a yield point, such as plasticized PVCmaterials, failure occurs at rupture of the geomembrane.3.1.7 force at specified elongation, FASE, na force asso-ciated with a specific elongation

23、 on the force-elongation curve.(Synonym for corresponding force.)3.1.8 force-elongation curve, nin a tensile test, a graphicalrepresentation of the relationship between the magnitude of anexternally applied force and the change in length of thespecimen in the direction of the applied force. (Synonym

24、 forstress-strain curve.)3.1.9 geomembrane, nan essentially impermeable geosyn-thetic used with foundation soil, rock, earth, or any othergeotechnical engineering-related material as an integral part ofa manmade project, structure, or system.3.1.9.1 DiscussionOther names under which geomem-branes ar

25、e recognized include: flexible membrane liners(FMLs), liners, and membranes.3.1.10 index test, na test procedure which may contain aknown bias, but which may be used to establish an order for aset of specimens with respect to the property of interest.3.1.11 inflection point, nthe first point of the

26、force-elongation curve at which the second derivative equals zero.3.1.11.1 DiscussionThe inflection point occurs at the firstpoint on the force-elongation curve at which the curve ceasesto curve upward and begins to curve downward (or vice versa).3.1.12 initial tensile modulus, Ji, (FL1), Nm1, nforg

27、eosynthetics, the ratio of the change in force per unit width tothe change in elongation of the initial portion of a force-elongation curve.3.1.13 offset modulus, Jo, (FL1), Nm1, nforgeosynthetics, the ratio of the change in force per unit width tothe change in elongation below an arbitrary offset p

28、oint atwhich there is a proportional relationship between force andelongation, and above the inflection point on the force-elongation curve.3.1.14 performance test, na test which simulates in thelaboratory as closely as practicable selected conditions expe-rienced in the field and which can be used

29、in design. (Synonymfor design test.)3.1.15 secant modulus, Jsec, (FL1), Nm1, nforgeosynthetics, the ratio of change in force per unit width to thechange in elongation between two points on a force-elongationcurve.3.1.16 tensile, adjcapable of tensions, or relating to ten-sion of a material.3.1.17 te

30、nsile modulus, J, (FL1), Nm1, nforgeosynthetics, the ratio of the change in tensile force per unitwidth to a corresponding change in elongation.3.1.18 tensile strength, nthe maximum resistance to de-formation developed by a specific material when subjected totension by an external force.3.1.19 tensi

31、le test, nfor geosynthetics, a test in which amaterial is stretched uniaxially to determine the force-elongation characteristics, the breaking force, or the breakingelongation.3.1.20 tension, nthe force that produces a specified elon-gation.3.1.21 wide strip tensile test, nfor geosynthetics, a tensi

32、letest in which the entire width of a 200-mm (8.0-in.) widespecimen is gripped in the clamps and the gauge length is100 mm (4.0 in.).3.1.22 work-to-break, W, (LF), J, nin tensile testing, thetotal energy required to rupture a specimen.3.1.22.1 DiscussionFor geomembranes, work-to-break isproportional

33、 to the area under the force-elongation curve fromthe origin to the breaking point.3.1.23 yield point, nin geosynthetics, the point on theforce-elongation curve at which the first derivative equals zero(the first maximum).3.1.24 For definitions of other terms used in this testmethod, refer to Termin

34、ologies D123 and 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 type tensiletesting machine operated at a prescribed rate of extension,applying a uniaxial load to the specimen until the specimenruptures. T

35、ensile strength, elongation, initial and secantmodulus, and breaking toughness of the test specimen can becalculated from machine scales, dials, recording charts, or aninterfaced computer.5. Significance and Use5.1 This test method is a performance test intended as adesign aid used to determine the

36、ability of geomembranes toD4885 01 (2018)2withstand the stresses and strains imposed under design con-ditions. This test method assists the design engineer in com-paring several candidate geomembranes under specific testconditions.5.2 As a performance test, this method is not intended forroutine acc

37、eptance testing of commercial shipments ofgeomembranes. Other more easily performed test methods,such as Test Methods D751 or Test Method D882, can be usedfor routine acceptance testing of geomembranes. This testmethod will be used relatively infrequently and to establishperformance characteristics

38、of geomembrane materials.5.2.1 There is no known correlation between this testmethod and index test methods, such as Test Methods D751.5.3 All geomembranes can be tested by this method. Somemodification of techniques may be necessary for a givengeomembrane depending upon its physical makeup. Special

39、adaptations may be necessary with strong geomembranes orgeomembranes with extremely slick surfaces, to prevent themfrom slipping in the clamps or being damaged by the clamps.6. Apparatus6.1 ClampsA gripping system that minimizes (with thegoal of eliminating) slippage, damage to the specimen, andunev

40、en stress distribution. The gripping system shall extend toor beyond the outer edge of the specimen to be tested.36.2 Specimen CutterAn appropriate cutting device whichdoes not create irregularities or imperfections in the edge of thespecimen. For wide strip specimens, a jig may not be necessaryprov

41、ided that the actual cut dimensions of the specimen can bemeasured accurately to the nearest 1.0 mm (0.04 in.), and thatthe width of the specimen is constant to within 1.0 mm(0.04 in.).6.3 Tensile Testing MachineA testing machine of theconstant rate of extension type as described in SpecificationD76

42、/D76M shall be used. The machine shall be equipped witha device for recording the tensile force and the amount ofseparation of the grips. Both of these measuring systems shallbe accurate to 62 % and, preferably, shall be external to thetesting machine. The rate of separation shall be uniform andcapa

43、ble of adjustment within the range of the test.7. Sampling7.1 Lot SampleDivide the product into lots and take thelot sample as directed in Practice D4354.7.2 Laboratory SampleFor the laboratory sample, take afull-width swatch approximately 1 m (40 in.) long in themachine direction from each roll in

44、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.7.3 Test SpecimensTake a total of twelve specimens fromeach swatch in the laboratory sample, with six specimens fortests in the machine dire

45、ction and six specimens for tests in thecross-machine direction. Take the specimens from a diagonalon the swatch, with no specimen nearer the edge of thegeomembrane than one-tenth of the width of the geomem-brane. Cut each specimen 200 mm (8.0 in.) wide by at least200 mm (8.0 in.) long, with the len

46、gth precisely aligned withthe direction in which the specimen is to be tested. Thespecimens must be long enough to extend completely throughboth clamps of the testing machine. Draw two parallel linesnear the center of each specimen length that: (1) are separatedby 100 mm (4.0 in.); (2) extend the fu

47、ll width of the specimen;and (3) are exactly perpendicular to the length of the specimen.Exercise the utmost care in selecting, cutting, and preparingspecimens to avoid nicks, tears, scratches, folds, or otherimperfections that are likely to cause premature failure.8. Conditioning8.1 Expose the spec

48、imens to the standard atmosphere fortesting geomembranes for a period long enough to allow thegeomembrane to reach equilibrium with the standard atmo-sphere. Consider the specimen to be at moisture equilibriumwhen the change in mass of the specimen in successiveweighings made at intervals of not les

49、s than 2 h does notexceed 0.1 % of the mass of the specimen. Consider thespecimen to be at temperature equilibrium after1hofexposureto the standard atmosphere for testing.9. Procedure9.1 Test adequately conditioned specimens. Conduct tests ata temperature of 21 6 2 C (70 6 4 F) and at a relativehumidity of 50 to 70 %. The engineer may specify additionaltemperatures based upon expected service conditions for theinstallation.9.2 Measure for the specimens thickness at the four cornersof the specimen. Select specimens used in this proced