1、Designation: D 7272 06Standard Test Method forDetermining the Integrity of Seams Used in JoiningGeomembranes by Pre-manufactured Taped Methods1This standard is issued under the fixed designation D 7272; 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method describes destructive quality controland/or quality assurance tests
3、to determine the integrity ofseams produced using taped seaming methods. This testmethod presents the procedures used for determining thequality of taped seams subjected to both peel and shear tests.These test procedures are intended for non-reinforced andreinforced geomembranes.1.2 The types of tap
4、e seaming techniques used to constructgeomembrane seams include the following.1.2.1 Inseam TapeThis technique requires the membraneto be overlapped a minimum distance. The top sheet is foldedback and both the bottom sheet and the top sheet are primedwith an adhesive primer. The primer is allowed to
5、flash-off. Thetape adhesive is applied to the bottom sheet so that a minimumof the tape will extend out from under the top sheet when laidover the tape. The top sheet is allowed to lay flat over the tapeand the release paper is removed by pulling it at a 45 to 90degree angle, keeping the release pap
6、er flat to the surface of thebottom sheet. The seam area is then rolled with a siliconesleeved roller.1.2.2 Cover Strip TapeThis technique requires the mem-brane to be overlapped a minimum distance.An area either sideof the seam edge is primed. The primer is allowed to flash-off.The cover strip is a
7、pplied with the adhesive side down centeredover the top sheet edge while removing the release paper as itproceeds along centered over the edge of the top sheet. Thecover strip is then rolled with a silicone sleeved roller.1.3 For nondestructive test methods, see Practice D 4437.1.4 This test method
8、is applicable for seaming processesthat use tape adhesive as a seaming mechanism.1.5 Subsequent decisions as to seam acceptance criteria aremade according to the site-specific contract plans, specifica-tions, and contractor quality control/contractor quality assur-ance (CQC/CQA) documents.1.6 In cas
9、e of a material specific test method, this testmethod shall take precedence.1.7 Hazardous MaterialsAlways consult the proper ma-terial safety data sheets for any hazardous material used for theproper ventilation and protection. The use of the oven in thesetest methods, in this practice, may accelera
10、te fume productionfrom the test specimen.1.8 The values stated in both inch-pound and SI units are tobe regarded separately as the standard. Values in parenthesesare for information only.1.9 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is t
11、heresponsibility 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 413 Test Methods for Rubber PropertyAdhesion toFlexible SubstrateD 638 Test Method
12、for Tensile Properties of PlasticsD 653 Terminology Relating to Soil, Rock, and ContainedFluidsD 882 Test Method for Tensile Properties of Thin PlasticSheetingD 4437 Practice for Determining the Integrity of FieldSeams Used in Joining Flexible Polymeric SheetGeomembranesD 4439 Terminology for Geosyn
13、theticsD 5199 Test Method for Measuring the Nominal Thicknessof GeosyntheticsD 5994 Test Method for Measuring Core Thickness ofTextured Geomembrane3. Terminology3.1 DefinitionsFor definitions of other geosynthetic termsused in this method, refer to Terminology D 4439. For defini-tions of soil terms,
14、 refer to Terminology D 653.3.2 Definitions of Terms Specific to This Standard: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 July 1, 2006. Published July 2006.2For re
15、ferenced 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, W
16、est Conshohocken, PA 19428-2959, United States.3.2.1 tape adhesive, nsolid strip of prefabricated or manu-factured adhesive factory laminated to a release paper used tojoin two polymer sheets.3.2.2 tape adhesive seam, nadhesive-based tape placedbetween two polymer sheet materials forming a surface b
17、ond.3.2.3 cover strip adhesive, nsolid strip of prefabricated ormanufactured adhesive factory laminated to layer of polymersheet material factory laminated to a release paper used to jointwo polymer sheets.3.2.4 cover strip adhesive seam, nadhesive-based lami-nated tape placed over two overlapping p
18、olymer sheet materi-als forming a surface bond.4. Significance and Use4.1 SignificanceWith the increased use of geomembranesas a barrier material to restrict liquid migration from onelocation to another, a need has been created for a standard testmethod to evaluate the quality of geomembrane seams p
19、ro-duced by tape methods. In the case of geomembranes, it hasbecome evident that geomembrane seams can exhibit separa-tion in the field under certain conditions. This is an index typetest method used for quality assurance and quality controlpurposes, it is also intended to provide the quality engine
20、erwith sufficient seam peel and shear data to evaluate seamquality.4.2 UseRecording 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 du
21、ring con-struction, and therefore, minimize the potential for seamseparation while in service. The acceptable value of adhesionmeasured will, of course, vary from product to product as aresult of different formulations and types of products. How-ever, once a product is established, minimum values of
22、separation force can be determined and agreed to by producerand consumer and both can monitor the installation to assuremaintenance of the agreed-upon minimum value.5. Apparatus5.1 Tensile instrumentation shall meet the requirementsoutlined in Test Method D 638 or D 882.5.2 A testing machine of the
23、constant-rate-of-cross headmovement type comprising essentially of the following:5.2.1 Fixed MemberA fixed or essentially stationarymember carrying one grip.5.2.2 Movable MemberA movable member carrying asecond grip.5.2.3 GripsGrips for holding the test specimen betweenthe fixed member and the movab
24、le member and minimizesboth slippage and uneven stress distribution. The grips shall beself-aligning so that they shall be attached to the fixed andmovable member, respectively, in such a manner that they willmove freely into alignment as soon as any load is applied, sothat the long axis of the test
25、 specimen will coincide with thedirection of the applied pull through the center line of the gripassembly. Grip faces shall be 25 mm (1 in.) wide and aminimum of 25 mm (1 in.) in length. Smooth surfaces, fineserrated or coarse serrated grip faces, use the grips that have allbeen found to be suitable
26、 for testing, depending on type ofgeomembrane seams that are being tested.NOTE 1Grips lined with thin rubber, crocus-cloth or pressure sensi-tive tape as well as file-faced or serrated grips have been successfully usedfor many materials. The choice of grip surface will depend on the materialtested,
27、thickness, etc.5.2.4 Drive MechanismA drive mechanism for impartingto the movable member in uniform, controlled velocity withrespect to the stationary member. Unless otherwise specified inthe material specification, the mechanism shall be capable ofand adjusted so that the movable member shall have
28、a uniformspeed of 50 mm/min, (2 in./min), 300 mm/min (12 in./min),and 500 mm/min (20 in./min).5.2.5 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 inertia lag
29、 at the specified rate of testing andshall indicate the load with an accuracy of 61 % of theindicated value or better.5.2.6 Extension Indicator (Extensometer) (If Employed)Asuitable instrument shall be used for determining the distancebetween two designated points within the gage length of thetest s
30、pecimen as the specimen is stretched and shall conform torequirements specified in Test Method D 638.6. Sampling and Specimen Preparation6.1 Trial Seam SampleA representative seam from eachseaming crew, fabricated from the same sheet material, andusing the seaming methods as those recommended by the
31、geomembrane fabricator manufacturer, shall be used for thismethod.6.1.1 Destructive Seam SampleAlternatively, cut a por-tion of the fabricated seam from the installed liner or a dailytest seam sample in accordance with the project specifications.It is recommended that the cutout sample be 0.3 m (1 f
32、t) wideand 0.45 m (1.5 ft) in length with the seam centered in themiddle of the seam.6.1.2 Specimen PreparationFive specimens shall be cutfrom the submittal sample for each the Peel and Shear test. Thespecimens for the Peel test shall be cut using a calibrated die,25 6 3 mm (nominal 1 6 0.125 in.) w
33、ide by 150 6 3mm(nominal 6 6 0.125 in.) long die. The Specimens for the Sheartest shall be die cut using a calibrated die, 25 6 3 mm (nominal1 6 0.125 in.) wide by 2 inches greater than the width of theseam. Specimens shall be such that the die is centered over thesample seam, perpendicular to the c
34、enterline of the seam. Peeland shear specimens shall be cut as shown in Fig. 1.6.1.3 ConditioningSamples should be conditioned for 24hours in a standard laboratory environment that conforms tothe requirements for testing geosynthetics as stated in Termi-nology D 4439. Long sample conditioning times
35、typically arenot possible for most applications that require daily seamtesting. Prior to testing, samples should be conditioned for aminimum of1hat216 2C and a relative humidity between50 and 70 %.NOTE 2Some adhesives may build up on the die. Dies need to beinspected and cleaned periodically. A non-
36、reactive release agent may beused on the die to reduce adhesive buildup, but type and frequency of useD7272062must be documented in test report.7. Destructive Test Methods7.1 Peel TestingSubject five specimens to the 180 “T-Peel” test (see Fig. 2). Maintaining the specimen in a horizontalposition th
37、roughout the test is not required. Fully grip the testspecimen across the width of the specimen. Grip the peelspecimen by securing grips 13 mm (12 in.) on each side of thestart of the seam bond. Apply a constant machine cross headspeed of 500 mm (20 in.)/ min. The test is complete when thespecimen r
38、uptures. The seam samples shall be tested inaccordance with Test Methods D 413 Method A. The indi-vidual specimens shall be 25 6 3mm(16 0.125 in.) wide andshall be cut with a standard calibrated die. The die shall becentered over the sample seam perpendicular to the centerlineof the seam. The grips
39、shall be positioned 25 mm (1 in.) apartwith no more than 13.5 mm (0.5 in.) on either side of the startof the seam bond (seam bond centered between the grip edges).The grip surfaces shall be acceptable for the testing of thespecific test material to prevent pullout. Grips shall be selfaligning so tha
40、t the axis of the test specimen will coincide withthe direction of the applied load through the centerline of thegrip assembly. The samples shall be inserted so that they arecentered and under no initial stress and fully supported acrossthe width of the seam. The seam overlap shall be as fabricated.
41、The specimens shall be pulled to rupture.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. The seam samples shall betested in accordance with Test Method D 882. The samplesshall be 25 mm (1 in.) wi
42、de by 50 mm (2 in.) greater that thewidth of the seam. The cut shall be centered over the seam,perpendicular to the centerline of the seam. Grip separationshall be 50 mm (2 in.) plus the width of the seam. The samplesshall be tested at a cross head speed of 500 mm (20 in.)/min.The grip surfaces shal
43、l be acceptable for the testing of thespecific material to prevent pullout. Grips shall be self aligningso that the axis of the test specimen will coincide with thedirection of the applied load through the centerline of the gripassembly. The seam overlap shall be as fabricated. Fullysupport the test
44、 specimen within the grips across the width ofthe specimen. The specimens shall be pulled to rupture or aspecified percent strain (that is, 50 %, 100 %, 200 %).NOTE 3Both peel and shear tests for fPP, LLDPE, VLDPE, EPDM,and PVC geomembranes have been tested routinely at both 2 and 20in./min. When co
45、nducting seam peel or shear testing for quality control, orquality assurance purposes, or both, it may be necessary to select themanufacturers recommended testing speed. In the absence of explicitFIG. 1 Seam SampleD7272063testing speed requirements, follow those recommended in 7.1 and 7.2.8. Calcula
46、tions 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 oflinear length of separated bond in the direction of the test, tothe length of original bonding to the near
47、est 25 %.8.2 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 shall be interpreted as occurring in themembrane that exhibits yielding.8.3 Shear Percent Elongat
48、ionCalculate the percent elon-gation on shear specimens according to Eq 1. Divide theextension at test end by the original gage length of 25 mm andmultiply by 100.Elongation 5 L/L03 100 (1)where:L = extension at test end, andL0= original gauge length.NOTE 4The intent of measuring elongation using th
49、is 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 definition 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 strain distribution which occurs in thespecimen during testing. Further,
