1、Designation: D7747 11Standard Test Method forDetermining Integrity of Seams Produced Using Thermo-Fusion Methods for Reinforced Geomembranes by the StripTensile Method1This standard is issued under the fixed designation D7747; the number immediately following the designation indicates the year ofori
2、ginal adoption 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 controltests us
3、ed to determine the integrity of thermo-fusion seamsmade with reinforced geomembranes. Test procedures aredescribed for seam tests for peel and shear properties usingstrip specimens.1.2 The types of thermal field and factory seaming tech-niques used to construct geomembrane seams include thefollowin
4、g.1.2.1 Hot AirThis technique introduces high-temperatureair between two geomembrane surfaces to facilitate melting.Pressure is applied to the top or bottom geomembrane, forcingtogether the two surfaces to form a continuous bond.1.2.2 Hot AirThis technique melts the two geomembranesurfaces to be sea
5、med by running a hot metal wedge betweenthem. Pressure is applied to the top and bottom geomembraneto form a continuous bond. Some seams of this kind are madewith dual tracks separated by a non-bonded gap. These seamsare sometimes referred to as dual hot wedge seams or double-track seams.1.2.3 Extru
6、sionThis technique encompasses extrudingmolten resin between two geomembranes or at the edge of twooverlapped geomembranes to effect a continuous bond.1.2.4 Radio Frequency (RF) or DielectricHigh frequencydielectric equipment is used to generate heat and pressure toform an overlap seam in factory fa
7、brication.1.2.5 ImpulseClamping bars heated by wires or a ribbonmelts the sheets clamped between them.Acooling period whilestill clamped allows the polymer to solidify before beingreleased.1.3 The types of materials covered by this test methodinclude, but are not limited to, reinforced geomembranes
8、madefrom the following polymers.1.3.1 Very Low Density Polyethylene (VLDPE).1.3.2 Linear Low Density Polyethylene (LLDPE).1.3.3 Flexible Polypropylene (fPP).1.3.4 Polyvinyl Chloride (PVC).1.3.5 Chlorosulfonated polyethylene (CSPE).1.3.6 Ethylene Interpolymer Alloy (EIA).1.4 UnitsThe values stated in
9、 either SI units or inch-pound units are to be regarded separately as standard. Thevalues stated in each system may not be exact equivalents;therefore, each system shall be used independently of the other.Combining values from the two systems may result in non-conformance with the standard.1.5 This
10、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 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2
11、.1 ASTM Standards:2D4439 Terminology for GeosyntheticsD7003 Test Method for Strip Tensile Properties of Rein-forced GeomembranesD7004 Test Method for Grab Tensile Properties of Rein-forced GeomembranesD76 Specification for Tensile Testing Machines for TextilesD7749 DESIG ATTRIBUTE D7749 HAD NO TITLE
12、 INSAD_TABLES3. Terminology3.1 DefinitionsRefer to Terminology for Geosynthetics,D4439 for definitions of terms applying to this test method.4. Significance and Use4.1 The use of reinforced geomembranes as barrier materi-als has created a need for a standard test method to evaluate thequality of sea
13、ms produced by thermo-fusion methods. This testmethod is used for quality control purposes and is intended toprovide quality control and quality assurance personnel withdata to evaluate seam quality.1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct r
14、esponsibility of Subcommittee D35.10 on Geomem-branes.Current edition approved Oct. 1, 2011. Published October 2011. DOI: 10.1520/D774711.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume
15、information, refer to the 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 This standard arose from the need for a destructive testmethod for evaluating seams of reinforced geomem
16、branes.Standards written for destructive testing of nonreinforcedgeomembranes do not include all Break Codes (figure 4)applicable to reinforced geomembranes.4.3 When reinforcement occurs in directions other thanmachine and cross machine, scrim are cut at specimen edges,generally lowering results. To
17、 partially compensate for this,testing can be performed according to D7749, or the 2 in. widestrip specimen specified in this method can be utilized. Testingof 1 in. and 2 in. specimens is Method A and method Brespectively.4.4 The shear test outlined in this method correlates tostrength of parent ma
18、terial measured according to ASTMD7003 only if reinforcement is parallel to TD. For othermaterials, seam strength and parent material strength can becompared through D7749 and D7004. Values obtained with thestrip methods shall not be compared to values obtained withgrab methods.5. Apparatus5.1 Tensi
19、le Testing MachineConstant Rate of Extension(CRE) equipment meeting the requirements of ASTM D76.The load cell shall be accurate to within +1% of the appliedforce. The drive mechanism shall be able to control the rate ofextension to within +1% of the targeted rate. The maximumallowable error in reco
20、rded grip displacement shall be 61% ofthe recorded values. The maximum allowable variation innominal gage length on repeated return of the clamps to theirstarting position shall be less than 0.25 mm (0.01 in.).5.2 Grip FacesThe clamping force and the clamp sur-faces shall hold the specimen firmly wi
21、thout causing damage.5.2.1 Clamp faces shall be a minimum of 25.4 mm (1.00 in)in the dimension parallel to direction of test and wide enoughto grip the full width of the specimen.6. Sample and Specimen Preparation6.1 Seam SamplesApproximately 1 m (36 in) length ofseam shall be cut out with a minimum
22、 of 12.5 cm (5 in) ofmaterial on either side of the seam6.2 Specimen PreparationFive specimens each for peelstrength and shear strength. The locations from which thespecimens are taken shall be spaced evenly along the length ofthe seam with shear and peel specimens alternating along thesample length
23、 (Fig. 1).6.2.1 SpecimensRectangular test specimens shall be aminimum of 150 mm (6.0 in) plus the seam width in thedirection perpendicular to the seam. For Method A, thespecimens shall be7. Conditioning7.1 ConditioningSpecimens may be tested once they haveequilibrated at standard laboratory temperat
24、ure. The timerequired to reach temperature equilibrium may vary accordingto the material type and thickness7.2 Test ConditionsConduct tests at the standard atmo-sphere for testing geosynthetics, a temperature of 21+2C(7064F) and a relative humidity between 50% to 70%, unlessotherwise specified.8. Pr
25、ocedure8.1 Shear Test8.1.1 Set the grip separation equal to the width of the seamplus 76.2 mm (3.00 in). Set the crosshead speed to 305mm/min (12 in/min).8.1.2 Place the specimen symmetrically in the clamps so theweld will experience shear force (Fig. 2). Center the seamvertically between the grips.
26、8.1.3 Elongate the specimen until rupture of reinforcementand coating or until a separation of weld or separation in planehas occurred across the entire weld. (see Fig. 4 for explanationof separation in plane).8.1.4 Record the load at peak and Break Code (Fig. 3 andFig. 4).8.2 Peel Test8.2.1 Set the
27、 grip separation to 25.4 mm/min (1.00 in). Setthe crosshead speed to 50.8 mm/min (2.00 in/min).8.2.2 Place the specimen in the clamps in a “T” configura-tion (Fig. 3). If there is enough material, center the seamvertically between the grips.8.2.3 Elongate the specimen until rupture of reinforcementa
28、nd coating or until a separation of weld or separation in planehas occurred across the entire weld. (see Fig. 4 for explanationof separation in plane)8.2.4 If a specimen slips between the clamps, discard theindividual result and test another specimen. If reinforcingstrands slip through the material
29、held between the grips,discard the individual result and test another specimen. Slip-ping scrim may require increasing clamping pressure.8.2.5 Record the load at peak, and Break Code (see Fig. 4and Fig. 5).9. Calculation9.1 Seam Shear Strength9.1.1 Divide the peak load by the width of the specimen t
30、oobtain results in N/mm or lbs/in.9.2 Seam Peel StrengthFIG. 1 Specimen configuration of seam sample.D7747 1129.2.1 Divide the peak load by the width of the specimen toobtain results in N/mm or lbs/in.10. Report10.1 The report shall include the following information10.1.1 Type of test: shear or peel
31、.10.1.2 Method A (1 in. specimen), or Method B (2 in.speci-men).10.1.3 Individual location of break code for each specimen.10.1.4 Shear tests:Individual seam shear strength for each specimen andaverage seam shear strength for all specimens in units of N/mmor lbs/in.10.1.5 Peel tests:Individual seam
32、peel strength for each specimen and averageseam peel strength for all specimens in units of N/mm orlbs/in., rate of extension.NOTE 1“Locus-of-Failure” (Fig. 4 and Fig. 5) include only some ofthe typically found seam configurations found in the industry. When thistest method is applied to seams bonde
33、d in configurations other than thoseidentified in Fig. 4 or Fig. 5, the users of this test method must agree onapplicable descriptions for modes of specimen rupture.10.1.6 If the specimen does not rupture, report this and themaximum extension achieved during the test.11. Precision and Bias11.1 No st
34、atement can be made at this time concerningprecision or bias.FIG. 2 Example of shear testFIG. 3 Example of peel testD7747 113FIG. 4 Break Codes for dual hot wedge and hot air seams of reinforced geomembranes tested for seam strength in shear and peelmodes.D7747 114FIG. 5 Break codes for fillet extru
35、sion weld seams in reinforced geomembranes tested for seam strength in peel and shear modes.D7747 115ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that det
36、ermination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved o
37、r withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel th
38、at your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints
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