ASTM D6392-12(2018) Standard Test Method for Determining the Integrity of Nonreinforced Geomembrane Seams Produced Using Thermo-Fusion Methods.pdf

1、Designation: D6392 12 (Reapproved 2018)Standard Test Method forDetermining the Integrity of Nonreinforced GeomembraneSeams Produced Using Thermo-Fusion Methods1This standard is issued under the fixed designation D6392; 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method describes destructive quality controland quality assu

3、rance tests used to determine the integrity ofgeomembrane seams produced by thermo-fusion methods.This test method presents the procedures used for determiningthe quality of nonbituminous bonded seams subjected to bothpeel and shear tests. These test procedures are intended fornonreinforced geomembr

4、anes only.1.2 The types of thermal field seaming techniques used toconstruct geomembrane seams include the following:1.2.1 Hot AirThis technique introduces high-temperatureair or gas between two geomembrane surfaces to facilitatemelting. Pressure is applied to the top or bottom geomembrane,forcing t

5、ogether the two surfaces to form a continuous bond.1.2.2 Hot Wedge (or Knife)This technique melts the twogeomembrane surfaces to be seamed by running a hot metalwedge between them. Pressure is applied to the top or bottomgeomembrane, or both, to form a continuous bond. Someseams of this kind are mad

6、e with dual bond tracks separated bya nonbonded gap. These seams are sometimes referred to asdual hot wedge seams or double-track seams.1.2.3 ExtrusionThis technique encompasses extrudingmolten resin between two geomembranes or at the edge of twooverlapped geomembranes to effect a continuous bond.1.

7、3 The types of materials covered by this test methodinclude the following:1.3.1 Very low-density polyethylene (VLDPE).1.3.2 Linear low-density polyethylene (LLDPE).1.3.3 Very flexible polyethylene (VFPE).1.3.4 Linear medium-density polyethylene (LMDPE).1.3.5 High-density polyethylene (HDPE).1.3.6 Po

8、lyvinyl chloride (PVC).1.3.7 Flexible polypropylene (fPP).NOTE 1The polyethylene identifiers presented in 1.3.1 1.3.5describe the types of materials typically tested using this test method.These are industry-accepted trade descriptions and are not technicalmaterial classifications based upon materia

9、l density.1.4 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, health, and environmental practices and deter-mine the applicability of regulatory limitations pr

10、ior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization Technical

11、Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D638 Test Method for Tensile Properties of PlasticsD4439 Terminology for GeosyntheticsD5199 Test Method for Measuring the Nominal Thicknessof GeosyntheticsD5994/D5994M Test Method for Measuring Core Thicknessof Textured Geo

12、membranes2.2 EPA Standard:3EPA/600/2-88/052 Lining of Waste Containment and OtherContainment Facilities, Appendix NLocus of BreakCodes for Various Types of FML Seams3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 geomembrane, nessentially impermeable geosyn-thetic composed of

13、one or more synthetic sheets.3.1.2 quality assurance, nall planned and systematic ac-tions necessary to provide adequate confidence that an item ora facility will perform satisfactorily in service.3.1.3 quality control, nthe operational techniques and theactivities which sustain a quality of materia

14、l, product, system,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 Feb. 1, 2018. Published February 2018. Originallyapproved in 1999. Last previous edition approved in

15、2012 as D6392 12. DOI:10.1520/D6392-12R18.2For 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 website.3Available from the

16、 Superintendent of Documents, US Government PrintingOffice, Washington, DC 20402.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 stan

17、dardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1or service that will satisfy given needs; also the use of suchtechniques and activities.

18、4. Significance and Use4.1 The use of geomembranes as barrier materials to restrictliquid migration from one location to another in soil and rockhas created a need for a standard test method to evaluate thequality of geomembrane seams produced by thermo-fusionmethods. In the case of geomembranes, it

19、 has become evidentthat geomembrane seams can exhibit separation in the fieldunder certain conditions. Although this is an index-type testmethod used for quality assurance and quality controlpurposes, it is also intended to provide the quality assuranceengineer with sufficient seam peel and shear da

20、ta to evaluateseam quality. Recording and reporting data, such as separationthat occurs during the peel test and elongation during the sheartest, will allow the quality assurance engineer to take measuresnecessary to ensure the repair of inferior seams during facilityconstruction, and therefore, min

21、imize the potential for seamseparation in service.5. Apparatus5.1 Tensile instrumentation shall meet the requirementsoutlined in Test Method D638.5.2 Grip FacesGrip faces shall be 25 mm (1 in.) wide anda minimum of 25 mm (1 in.) in length. Smooth rubber, fineserrated, or coarse serrated grip faces h

22、ave all been found to besuitable for testing geomembrane seams.6. Sample and Specimen Preparation6.1 Seam SamplesCut a portion of the fabricated seamsample from the installed liner in accordance with the projectspecifications. It is recommended that the cutout sample be0.3 m (1 ft) wide and 0.45 m (

23、1.5 ft) in length with the seamcentered in the middle.6.2 Specimen PreparationTen specimens shall be cutfrom the sample submittal. The specimens shall be die cutusing a 25 mm (nominal 1 in.) wide by a minimum of 150 mm(nominal 6 in.) long die. Specimens that will be subjected topeel and shear tests

24、shall be selected alternately from thesample and labeled as shown in Fig. 1. Specimens shall be cutsuch that the seam is perpendicular to the longer dimension ofthe strip specimen.6.3 ConditioningSamples should be conditioned for 40 hin a standard laboratory environment that conforms to therequireme

25、nts for testing geosynthetics as stated in TerminologyD4439. Long sample conditioning times typically are notpossible for most applications that require seam testing. Priorto testing, samples should be conditioned for a minimum of 1 hat 23 6 2 C and a relative humidity between 50 and 70 %.7. Destruc

26、tive Test Methods7.1 Peel TestingSubject five specimens to the 90 “T-peel” test (see Fig. 2). If the tested sample is a dual hot wedgeseam, five specimens must be examined for each external trackof the seam. Maintaining the specimen in a horizontal positionthroughout the test is not required. Fully

27、grip the test specimenacross the width of the specimen. Grip the peel specimen bysecuring grips 25 mm (1 in.) on each side of the start of theseam bond, a constant machine crosshead speed of 50 mm(2 in.) min for HDPE, LMDPE, and PVC, 500 mm (20in.)/min for LLDPE, VLDPE, VFPE, and fPP. The test iscom

28、plete when the specimen ruptures.7.2 Shear TestingSubject five specimens to the shear test(see Fig. 2). Fully support the test specimen within the gripsacross the width of the specimen. Secure the grips 25 mm(1 in.) on each side of the start of the seam bond, a constantmachine crosshead speed of 50

29、mm (2 in.)/min for LMDPEand HDPE, 500 mm (20 in.)/min for fPP, LLDPE, VFPE,VLDPE, and PVC. The test is complete for HDPE and LMDPEFIG. 1 Seam SampleD6392 12 (2018)2once the specimen has elongated 50 %. PVC, fPP, LLDPE,VFPE, and VLDPE geomembranes should be tested to rupture.NOTE 2Both peel and shear

30、 tests for fPP, LLDPE, VLDPE, and PVCgeomembranes have been tested routinely at both 2 and 20 in./min. Whenconducting seam peel or shear testing for quality control or qualityassurance purposes, or both, it may be necessary to select the manufac-turers recommended testing speed. In the absence of ex

31、plicit testingspeed requirements, follow those recommended in 7.1 and 7.2.8. Calculations and Observations8.1 Estimate of Seam Peel SeparationVisually estimatethe seam separation demonstrated prior to rupture for peelspecimens. The estimate shall be based upon the proportion ofthe area of the separa

32、ted bond, to the area of original bondingto the nearest 5 %. However, if at any point across the width ofthe peel specimen seam separation continues to the other sideof the bonded area, the estimate of seam peel separation shallbe 100 % regardless of the proportion of the area of theseparated bond t

33、o the area of the original bonding.8.1.1 In cases of dispute, the peel separation estimate maybe documented via direct measure.8.1.2 ProcedureDetermine the total area of bonded areafor which the peel test was performed using calipers to spanmeasure the maximum length of the bond, being careful notin

34、clude squeeze-out or tack-welded areas. Verify the seamwidth of one inch.8.1.3 Assign appropriate geometric shapes to approximatethe area of each separated portion of the peeled zone.8.1.4 Place the peeled specimen flat against the surface of aflatbed scanner set at 100 % scale.8.1.5 Produce a recor

35、d of the peeled area for easier shapeassignment and peeled area determination. Care should betaken to ensure intimate contact between the peeled specimenand the scanner surface so as to preserve dimensions.8.1.6 Using the same calipers, record the dimensions ofeach peeled area.8.1.7 Using the record

36、ed dimensions, calculate percent peelas follows and round to the nearest 5%.S 5 100* AAo(1)where:S = percent peel separation,A = area of peel separation measured, andAo= area of original bonded region (not including trackweld, tack weld, or squeeze-out, see Notes 3 and 4).NOTE 3During the thermo-fus

37、ion welding process, some of themelted polymer may be shifted to the outside of the weld during thepressing of the geomembrane panels together. This melted polymer issometimes called “squeeze-out” or “bleed-out” and is not considered partof the bond. Care must be exercised during estimation of the s

38、eam peelseparation to segregate the squeeze or bleed-out area from the peeled bondarea. The reported peel separation shall include the peeled bond area only.NOTE 4The exact area of original bond (Ao) for use in Eq 1 for peelseparation is sometimes ambiguous. For most cases, the area of peelmeasured

39、for thermo-fusion extrusion seams is that area defined by thewidth of the specimen multiplied by the distance between the terminationof the top geomembrane and the outermost edge of the extrusion weldalong the bottom geomembrane. To be counted as part of the weld, theextruded material must be at lea

40、st as thick as the nominal thickness of thegeomembrane.FIG. 2 Shear and T-Peel SpecimensD6392 12 (2018)38.2 Rupture Mode SelectionDetermine the locus of breakfor both the peel and shear specimens as shown in Figs. 3 and4. The locus of break for shear specimens that do not ruptureprior to test end (5

41、0 % elongation) shall be interpreted asoccurring in the membrane that exhibits yielding.8.3 Shear Percent ElongationCalculate the percent elon-gation on shear specimens according to Eq 2. Divide theextension at test end by the original gage length of 25 mm andmultiply by 100.ElongationE! 5LL03100 (2

42、)where:L = extension at test end, andL0= original gauge length.NOTE 5The intent of measuring elongation using this test method isto identify relatively large reductions in typical break elongation values ofseam samples. Length is defined as the distance from one grip to the seamedge. Using this defi

43、nition implies that all strain experienced by thespecimen during the shear test occurs on one side of the seam. Of coursethis assumption is inaccurate, since some strain will occur on each side ofthe seam, and in the seam area itself; however, it is difficult to make anaccurate measurement of the st

44、rain distribution which occurs in thespecimen during testing. Further, it is not critical to know the exactlocation of all the strain which occurs during testing but rather to simplyidentify when significant reductions in elongation (when compared withthe typical elongation of a new material) have o

45、ccurred.9. Report9.1 The report shall include the following information:9.1.1 Report the individual peel and shear specimen maxi-mum unit tension values in N/mm of width (lb/in.).NOTE 6If requested, report the maximum peel or shear stress. Thiscalculation will require an accurate measurement of thic

46、kness for eachspecimen. These measurements should be made in accordance with TestMethod D5199 for smooth geomembranes and Test Method D5994/D5994M for textured geomembranes.9.1.2 Report the crosshead speed used during peel and sheartesting.9.1.3 Report the average of the individual peel and shearsam

47、ple values recorded.9.1.4 If the peel or shear specimen does not rupture, reportthe elongation at the maximum crosshead travel limitation. Ifthe gage length is reduced to less than 25 mm (1 in.), this mustbe noted in the report.9.1.5 Report the mode of specimen rupture for peel andshear specimens ac

48、cording to Fig. 3 or Fig. 4.FIG. 3 Locus-of-Break Codes for Dual Hot Wedge Seams in Unreinforced Geomembranes Tested for Seam Strength in Shear and PeelModesD6392 12 (2018)4NOTE 7“Locus of failure” (Figs. 3 and 4) includes only some of thetypically found seam configurations found in the industry. Wh

49、en this testmethod is applied to seams bonded in configurations other than thoseidentified in Fig. 3 or Fig. 4, the users of this test method must agree onapplicable descriptions for modes of specimen rupture.10. Precision and Bias10.1 No statement can be made at this time concerningprecision or bias.FIG. 4 Locus-of-Break Codes for Fillet Extrusion Weld Seams in Unreinforced Geomembranes Tested for Seam Strength in Shear andPeel ModesD6392 12 (2018)5ASTM International takes no position respecting the validity of any pate