ASTM D7272-06(2011)

Significance—With the increased use of geomembranes as a barrier material to restrict liquid migration from one location to another, a need has been created for a standard test method to evaluate the quality of geomembrane seams produced by tape methods. In the case of geomembranes, it has become evident that geomembrane seams can exhibit separation in the field under certain conditions. This is an index type test method used for quality assurance and quality control purposes, it is also intended to provide the quality engineer with sufficient seam peel and shear data to evaluate seam quality.

Use—Recording and reporting data such as separation that occurs during the peel test and elongation during the shear test, will allow the quality assurance engineer to take measures necessary to ensure the repair of inferior seams during construction, and therefore, minimize the potential for seam separation while in service. The acceptable value of adhesion measured will, of course, vary from product to product as a result of different formulations and types of products. However, once a product is established, minimum values of separation force can be determined and agreed to by producer and consumer and both can monitor the installation to assure maintenance of the agreed-upon minimum value.

1.1 This test method describes destructive quality control and/or quality assurance tests to determine the integrity of seams produced using taped seaming methods. This test method presents the procedures used for determining the quality of taped seams subjected to both peel and shear tests. These test procedures are intended for non-reinforced and reinforced geomembranes.

1.2 The types of tape seaming techniques used to construct geomembrane seams include the following.

1.2.1 Inseam Tape—This technique requires the membrane to be overlapped a minimum distance. The top sheet is folded back and both the bottom sheet and the top sheet are primed with an adhesive primer. The primer is allowed to flash-off. The tape adhesive is applied to the bottom sheet so that a minimum of the tape will extend out from under the top sheet when laid over the tape. The top sheet is allowed to lay flat over the tape and the release paper is removed by pulling it at a 45 to 90 degree angle, keeping the release paper flat to the surface of the bottom sheet. The seam area is then rolled with a silicone sleeved roller.

1.2.2 Cover Strip Tape—This technique requires the membrane to be overlapped a minimum distance. An area either side of the seam edge is primed. The primer is allowed to flash-off. The cover strip is applied with the adhesive side down centered over the top sheet edge while removing the release paper as it proceeds along centered over the edge of the top sheet. The cover strip is then rolled with a silicone sleeved roller.

1.3 For nondestructive test methods, see Practice D4437.

1.4 This test method is applicable for seaming processes that use tape adhesive as a seaming mechanism.

1.5 Subsequent decisions as to seam acceptance criteria are made according to the site-specific contract plans, specifications, and contractor quality control/contractor quality assurance (CQC/CQA) documents.

1.6 In case of a material specific test method, this test method shall take precedence.

1.7 Hazardous Materials—Always consult the proper material safety data sheets for any hazardous material used for the proper ventilation and protection. The use of the oven in these test methods, in this practice, may accelerate fume production from the test specimen.

1.8 The values stated in both inch-pound and SI units are to be regarded separately as the standard. Values in parentheses are for information only.

1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.