ASTM_D_7749_-_11.pdf

Designation:D774911Standard Test Method forDetermining Integrity of Seams Produced Using Thermo-Fusion Methods for Reinforced Geomembranes by the GrabMethod1This standard is issued under the fixed designation D7749;the number immediately following the designation indicates the year oforiginal 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 used to determine the integrity of thermo-fusion seamsmade with reinforced geomembranes.A test procedure isdescribed that uses seam tests using grab specimens for seamshear strength.1.2 The types of thermal field and factory seaming tech-niques used to construct geomembrane seams include thefollowing.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 WedgeThis technique melts the two geomem-brane surfaces to be seamed by running a hot metal wedgebetween them.Pressure is applied to the top and bottomgeomembrane to form a continuous bond.Some seams of thiskind are made with dual tracks separated by a non-bonded gap.These seams are sometimes referred to as dual hot wedgeseams 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.1.2.4 Radio Frequency(RF)or DielectricHigh frequencydielectric equipment is used to generate heat and pressure toform an overlap seam in factory fabrication.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 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 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 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 Documents2.1 ASTM Standards:2D4439 Terminology for GeosyntheticsD7004 Test Method for Grab Tensile Properties of Rein-forced GeomembranesD7003 Test Method for Strip Tensile Properties of Rein-forced GeomembranesD76 Specification for Tensile Testing Machines for Textiles3.Terminology3.1 Definitions-Refer 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 seams 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 responsibility of Subcommittee D35.10 on Geomem-branes.Current edition approved Oct.1,2011.Published October 2011.DOI:10.1520/D7749112For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.2 Values obtained with this method can be correlatedtoD7004.The purpose of correlating these methods was for thestrength of parent material measured in to be comparable toseam strength measured by the test outlined here.The valueobtained with this method cannot be compared to values forstrip method D7003 for parent material or ASTM DXXXXstrip method for reinforced seams.5.Apparatus5.1 Tensile Testing MachineConstant Rate of Extension(CRE)equipment meeting the requirements of D76.The loadcell shall be accurate to within+1%of the applied force.Thedrive mechanism shall be able to control the rate of extensionto within+1%of the targeted rate.The maximum allowableerror in recorded grip displacement shall be 61