1、Designation: D 6693 04Standard Test Method forDetermining Tensile Properties of NonreinforcedPolyethylene and Nonreinforced Flexible PolypropyleneGeomembranes1This standard is issued under the fixed designation D 6693; the number immediately following the designation indicates the year oforiginal ad
2、option or, in the case of revision, the year of last 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 determination of the tensileproperties of
3、 nonreinforced geomembranes in the form ofstandard dumbbell-shaped test specimens when tested underdefined conditions of pretreatment, temperature, and machinespeed.1.2 This test method can be used for testing materialsthickness between 0.25 mm (0.010 in) and 6.3 mm (0.25 in.).NOTE 1This test method
4、 is not intended to cover precise physicalprocedures. The constant rate of crosshead movement of this test lacksaccuracy from a theoretical standpoint. A wide difference may existbetween the rate of crosshead movement and the rate of strain of thespecimen indicating that the testing speeds specified
5、 may disguiseimportant effects or characteristics of these materials in the plastic state.Further, it is realized that variations in the thicknesses of test specimens,as permitted by this test method, produce variations in the surface-volumeratios of such specimens, and that these variations may inf
6、luence the testresults. Hence, where directly comparable results are desired, all samplesshould be of equal thickness. Special additional tests should be used wheremore precise physical data are needed.1.3 Test data obtained by this test method are relevant andmay be appropriate for use in engineeri
7、ng design with consid-eration of test conditions as compared with in-service condi-tions.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.5 This standard does not purport to address all of thesafety concerns, if any, assoc
8、iated with its use. It is theresponsibility 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:2D 638 Test Method for Tensile Properties of PlasticsD 4000
9、 Classification System for Specifying Plastic Mate-rialsD 4439 Terminology for GeosyntheticsD 5199 Test Method for Measuring Nominal Thickness ofGeosyntheticsD 5994 Test Method for Measuring Core Thickness ofTextured GeomembraneE 4 Practices for Force Verification of Testing MachinesE 691 Practice f
10、or Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 DefinitionsDefinitions of terms applying to this testmethod appear in Terminology D 4439.4. Significance and Use4.1 This test method is designed to produce tensile propertydata for the control and spec
11、ification of nonreinforced poly-ethylene and flexible nonreinforced polypropylene geomem-branes. These data are also useful for qualitative characteriza-tion and for research and development. It may be necessary tomodify this procedure for use in testing certain materials asrecommended by the materi
12、al specifications. Therefore, it isadvisable to refer to that materials specification before usingthis test method. Table 1 in Classification D 4000 lists theASTM materials standards that currently exist.4.2 Tensile properties may vary with specimen preparation,test speed, and environment of testing
13、. Consequently, whereprecise comparative results are desired, these factors must becarefully monitored and controlled.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 Ju
14、ne 1, 2004. Published July 2004. Originally approvedin 2001. Last previous edition approved in 2003 as D 6963 03.2For 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
15、 standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2.1 It is realized that a material cannot be tested withoutalso testing the method of preparation of that material. Hence,when comp
16、arative tests of materials are desired, the care mustbe exercised to ensure that all samples are prepared in exactlythe same way, unless the test is to include the effects of samplepreparation. Similarly, for referee purposes or comparisonswithin any given series of specimens, care must be taken tos
17、ecure the maximum degree of uniformity in details of prepa-ration, treatment, and handling.NOTE 2Tensile properties may provide useful data for plastics engi-neering design purposes. However, because of the high degree ofsensitivity exhibited by many plastics to rate of straining and environ-mental
18、conditions, data obtained by this test method cannot be consideredvalid for applications involving load-time scales or environments widelydifferent from those of this test method. In cases of such dissimilarity, noreliable estimation of the limit of usefulness can be made for most plastics.This sens
19、itivity to rate of straining and environment necessitates testingover a broad load-time scale and range of environmental conditions iftensile properties are to suffice for engineering design purposes.5. Apparatus5.1 Testing MachineA testing machine of the constant-rate-of-crosshead-movement type and
20、 comprising essentiallythe following:5.1.1 Fixed MemberA fixed or essentially stationarymember carrying one grip.5.1.2 Movable MemberA movable member carrying asecond grip.5.1.3 GripsGrips for holding the test specimen betweenthe fixed member and the movable member of the testapparatus can be either
21、 a fixed or self-aligning type.5.1.3.1 Fixed grips are rigidly attached to the fixed andmovable members of the test apparatus. Extreme care shouldbe taken when this type of grip is used to ensure that the testspecimen is inserted and clamped so that the long axis of thetest specimen coincides with t
22、he direction of pull through thecenterline of the grip assembly.5.1.3.2 Self-aligning grips are attached to the fixed andmovable members of the test apparatus. This type of gripassembly is such that they will move freely into alignment assoon as any load is applied as long as the long axis of the te
23、stspecimen will coincide with the direction of the applied pullthrough the centerline of the grip assembly. The specimensshould be aligned as perfectly as possible with the direction ofpull so that no rotary motion will occur in the grips therebyinducing slippage; there is a limit to the amount of m
24、isalign-ment self-aligning grips will accommodate.5.1.3.3 The test specimen shall be held in such a way thatslippage relative to the grips is prevented as much as possible.Grip surfaces that are deeply scored or serrated with a patternsimilar to those of a coarse single-cut file, serrations about 2.
25、4mm (0.09 in) apart and about 1.6 mm (0.06 in.) deep, havebeen found satisfactory for most thermoplastics. Finer serra-tions have been found to be more satisfactory for harderplastics, such as the thermosetting materials. The serrationsshould be kept clean and sharp. Breaking in the grips mayoccur a
26、t times, even when deep serrations or abraded specimensurfaces are used; other techniques must be used in these cases.Other techniques that have been found useful, particularly withsmooth-faced grips, are abrading that portion of the surface ofthe specimen that will be in the grips, and interposing
27、thinpieces of abrasive cloth, abrasive paper, plastic, or rubber-coated fabric, commonly called hospital sheeting, between thespecimen and the grip surface. No. 80 double-sided abrasivepaper has been found effective in many cases. An open-meshfabric, in which the threads are coated with abrasive, ha
28、s alsobeen effective. Reducing the cross-sectional area of the speci-men may also be effective. The use of special types of grips issometimes necessary to eliminate slippage and breakage in thegrips.5.1.4 Drive MechanismA drive mechanism for impartingto the movable member a uniform, controlled veloc
29、ity withrespect to the stationary member, with this velocity to beregulated as specified in Section 9.5.1.5 Load IndicatorA suitable load-indicating mecha-nism capable of showing the total tensile load carried by thetest specimen when held by the grips. This mechanism shall beessentially free of ine
30、rtia lag at the specified rate of testing andshall indicate the load with an accuracy of 61 % of theindicated value, or better. The accuracy of the testing machineshall be verified in accordance with Practices E 4.NOTE 3Experience has shown that many testing machines now in useare incapable of maint
31、aining accuracy for as long as the periods betweeninspection recommended in Practices E 4. Hence, it is recommended thateach machine be studied individually and verified as often as may befound necessary. It frequently will be necessary to perform this functiondaily.6. Test Specimens6.1 Sheet, Plate
32、, and Molded Plastics:6.1.1 The test specimens shall conform to the dimensionsshown in Fig. 1. This specimen geometry was adopted fromTest Method D 638 and is therefore equivalent to Type IV ofsaid standard.6.1.2 Test specimens shall be prepared by die cutting frommaterials in sheet, plate, slab, or
33、 similar form.6.2 All surfaces of the specimen shall be free of visibleflaws, scratches, or imperfections. If the specimen exhibitssuch markings, it should be discarded and replaced. If theseflaws or imperfections are present in the new specimen, the dieshould be inspected for flaws.NOTE 4Negative e
34、ffects from imperfections on the edge of thespecimens can severely impact the results of this test and should thereforebe carefully monitored. In cases of dispute over the results, inspection ofthe die and specimen preparation should take place.7. Conditioning7.1 ConditioningSpecimens should be test
35、ed once thematerial has reached temperature equilibrium. The time re-quired to reach a temperature equilibrium may vary accordingto the manufacturing process, material type, and materialthickness.7.2 Test ConditionsConduct tests in the Standard Labora-tory Atmosphere of 21 6 2C (69.8 6 3.6F) unless
36、otherwisespecified in the test methods.NOTE 5A humidity requirement has intentionally been left out of thetest conditions due to the fact that polyolefins are not significantly affectedD6693042by large fluctuations in humidity thereby making such a restrictionunnecessary.NOTE 6The tensile properties
37、 of some plastics change rapidly withsmall changes in temperature. Since heat may be generated as a result ofstraining the specimen at high rates, conduct tests without forced coolingto ensure uniformity of test conditions. Measure the temperature in thereduced section of the specimen and record it
38、for materials whereself-heating is suspected.8. Number of Test Specimens8.1 Test at least five specimens for each sample in the caseof isotropic materials.8.2 Test ten specimens, five normal to and five parallel withthe principle axis of anisotropy, for each sample in the case ofanisotropic material
39、s.8.3 Discard specimens that break at some obvious flaw andprepare new specimens for retest, unless such flaws constitutea variable to be studied.9. Speed of Testing9.1 Speed of testing shall be the relative rate of motion ofthe grips or test fixtures during the test. The rate of motion ofthe driven
40、 grip or fixture when the test apparatus is running idlemay be used, if it can be shown that the resulting speed oftesting is within the limits of variation allowed.9.2 The test speed shall be 50 mm/min (2 in./min) forpolyethylene geomembranes and 500 mm/min (20 in./min) fornonreinforced flexible po
41、lypropylene geomembranes.NOTE 7Some nonreinforced polyethylene materials approaching butless than a density of 0.940 g/cc exhibit less variation when tested at 2 ipmrather than 20 ipm. If a test speed other than that indicated in 9.2 is used,this modification should be noted in the report.10. Proced
42、ure10.1 Measure the width and thickness of rigid flat speci-mens (Fig. 1) in accordance with Test Method D 5199 forsmooth geomembranes and Test Method D 5994 for textured(non-smooth) geomembranes.10.2 Place the specimen in the grips of the test apparatus,taking care to align the long axis of the spe
43、cimen and the gripswith an imaginary line joining the points of attachment of thegrips to the machine. The distance between the ends of thegripping surfaces, when using flat specimens, shall be asindicated in Fig. 1. Tighten the grips evenly and firmly to thedegree necessary to prevent slippage of t
44、he specimen duringthe test, but not to the point where the specimen would becrushed.10.3 Set the speed of testing at the proper rate in accordancewith Section 9, and start the machine.FIG. 1 Type IV Dog Bone SpecimenTABLE 1 Specimen Dimensions for Type IV Dog Bone of Thickness, T, mm (in.)Descriptio
45、n Dimension, mm (in.) Tolerances, mm (in.)Wwidth of narrow section 6 (0.25) 60.5 (60.02)Llength of narrow section 33 (1.30) 60.5 (60.02)GLYgage length for yield 33 (1.30) 60.5 (60.02)GLBgage length for break 50 (2.0) 60.5 (60.02)WOwidth overall 19 (0.75) 66.4 (60.25)LOlength overall 115 (4.5) No max
46、, No minGgage length 25 (1.00) 60.5 (60.02)Ddistance between grips 65 (2.5) 60.13 (60.005)Rradius of fillet 14 (0.56) 61(60.04)ROouter radius 25 (1.00) 61(60.04)D669304310.4 Record the load-extension curve of the specimen.10.5 Record the load and extension at the yield point (if oneexists) and the l
47、oad and extension at the moment of rupture(break point).11. Calculation11.1 Tensile Yield StrengthCalculate the load correspond-ing to the yield point in newtons (or pounds-force). Divide thatload by the original minimum width of the specimen in metres(or inches). Express the result in newtons per m
48、illimetre (orpounds-force per inch) and report it to three significant figuresas tensile yield strength.11.2 Tensile Break StrengthCalculate the load corre-sponding to the point of rupture (break) in newtons (orpounds-force). Divide that load by the original minimum widthof the specimen in metres (o
49、r inches). Express the result innewtons per millimetre (or pounds-force per inch) and report itto three significant figures as tensile break strength.11.3 Percent Yield ElongationCalculate percent elonga-tion at the yield point by reading the extension (change in gagelength) at the moment the applicable load is reached. Dividethat extension by the gage length for yield listed in Fig. 1(GLY) and multiply by 100. Report percent yield elongation tothe nearest 1%.11.4 Percent Break ElongationCalculate percent elonga-tion at the break point by reading the
