ASTM_D_5397_-_07_2012.pdf

Designation:D539707(Reapproved 2012)Standard Test Method forEvaluation of Stress Crack Resistance of PolyolefinGeomembranes Using Notched Constant Tensile Load Test1This standard is issued under the fixed designation D5397;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 is used to develop test data from whichthe susceptibility of polyolefin geomembrane sheet material tostress cracking under a constant tensile load condition and anaccelerated environmental condition can be evaluated.1.2 This test method measures the failure time associatedwith a given test specimen at a specified tensile load level.Results from a series of such tests utilizing a range of loadlevels can be used to construct a stress-time plot on a log-logaxis.1.3 The values stated in SI units are to be regarded as thestandard.The inch-pound units given in parentheses areprovided for information only.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D638 Test Method for Tensile Properties of PlasticsD883 Terminology Relating to PlasticsD4354 Practice for Sampling of Geosynthetics and RolledErosion Control Products(RECPs)for TestingD4833 Test Method for Index Puncture Resistance ofGeomembranes and Related Products3.Terminology3.1 Definitions:3.1.1 geomembrane,nvery low permeability syntheticmembrane liners or barriers used with any geotechnical engi-neering related material so as to control fluid migration in aman-made project,structure,or system(see Test MethodD4833).3.1.2 stress crack,nan external or internal crack in aplastic caused by tensile stresses less than its short-timemechanical strength(see Definitions D883).3.1.2.1 DiscussionThe development of such cracks isfrequently accelerated by the environment to which the plasticis exposed.The stresses that cause cracking may be presentinternally or externally or may be combinations of thesestresses.4.Summary of Test Method4.1 This test method consists of subjecting a dumbbellshaped notched test specimen from a polyolefin sheet to aconstant tensile load in the presence of a surface-active agentand at an elevated temperature.The time to failure of the testspecimen is recorded.The results of a series of such testsconducted at different stress levels are presented by plottingstress level against failure time for each stress level on alog-log axis.5.Significance and Use5.1 This test method does not purport to interpret theresulting response curve.Such interpretation is left to theparties involved in the commissioning and reporting of the testresults.5.2 This test method is intended as an index test and may beused for grading polyolefin geomembrane sheets in regard totheir stress cracking sensitivity.5.2.1 Conditions that can affect stress cracking include:levelofloading,testtemperatureandenvironment,microstructure,polymer additive package,processing history,and thermal history.6.Apparatus6.1 Blanking DieA die suitable for cutting test specimensto the dimensions and tolerances shown in Fig.1.NOTE1The length of the specimen can be changed to suit the designof the test apparatus.However,there should be a constant neck sectionwith length at least 13 mm(0.5 in.)long.The width should be 3.20 mm(0.125 in.).1This test method is under the jurisdiction of ASTM Committee D35 onGeosynthetics and is the direct responsibility of Subcommittee D35.02 on Endur-ance Properties.Current edition approved July 1,2012.Published July 2012.Originally approvedin 1993.Last previous edition approved in 2007 as D5397 07.DOI:10.1520/D5397-07R12.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.2 Notching DeviceAdevice or machine that can producea consistent notch depth.3NOTE2An evaluation of the notching technique can be performed byquenching a notched specimen in liquid nitrogen and then fracturing it.The notch depth can readily be measured by examining the fracturesurface under a reflected light microscope.Other methods of verifyingnotch depth include viewing the cut specimen on its side in a microscopewith the aid of a eyepiece micrometer or a calibrated reticle.6.3 BladeA single-edged razor made of carbon steel.Thetip profile is that of an arrow rather than that of a chisel point.The sharpness o