ASTM_D_7406_-_07_2012.pdf

Designation:D740607(Reapproved 2012)Standard Test Method forTime-Dependent(Creep)Deformation Under ConstantPressure for Geosynthetic Drainage Products1This standard is issued under the fixed designation D7406;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 determine the unconfinedcompressive creep characteristics of drainage geotextiles,geocomposites,geonets,or any other geosynthetic associatedwith drainage at a constant temperature,when subjected to aconstant compressive stress.1.2 This test method is intended for use as an unconfinedcompressive performance creep test only.For a detailedprocedure on how to establish an index test see the EN standard1897.For performance tests,the specimen shall be subjected tothe site-specific liquid and/or the site-specific stress(normaland potentially shear stress).NOTE1Results achieved from unconfined compressive performancecreep may differ from testing performed under confined conditions.1.3 Because of the changing nature of the geosyntheticindustry,and the wide variety of products already available,this particular test method may have to be slightly modified forunconfined compression creep testing of some products.1.4 The values given in SI units are to be considered as thestandard.The values given in parentheses are for informationonly.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:2D2990 Test Methods for Tensile,Compressive,and FlexuralCreep and Creep-Rupture of PlasticsD4439 Terminology for GeosyntheticsD5199 Test Method for Measuring the Nominal Thicknessof GeosyntheticsD5261 Test Method for Measuring Mass per Unit Area ofGeotextilesD5262 Test Method for Evaluating the Unconfined TensionCreep and Creep Rupture Behavior of GeosyntheticsD6364 Test Method for Determining Short-Term Compres-sion Behavior of Geosynthetics2.2 EN Standard:EN 18973.Terminology3.1 For definitions related to geosynthetics,see Terminol-ogy D4439.3.2 For definitions related to creep,see Test Methods D2990and D5262.3.3 Definitions:3.3.1 compressive creep,ntime-dependent deformation orcompressive strain of a material subjected to a constantcompressive stress.3.3.2 compressive creep rupture,nfailure by collapse of amaterial subjected to a constant compressive stress.4.Summary of Test Method4.1In this performance test method,a geosynthetic drain-age product is subjected to a sustained normal and potentiallyshear stresses.Deformations of the specimen are recorded atdesignated time intervals,and a graph is drawn.4.2 The specimen may be immersed in a site-specific wateror permeant,to simulate actual field conditions.4.3 For long-term testing it is recommended that the test berun for at least 1000 h.Dwell times up to 10000 hr have beenused,if that longer time data is required.4.4 Creep load(normal as well as potentially shear)shouldreflect the actual field conditions4.5 The test will be conducted at site specific temperatures.5.Significance and Use5.1 The performance characteristics of a drainage geosyn-thetic are directly related to the integrity under compressive1This 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.DOI:10.1520/D7406-07R12.2For 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 loading.If the product is sensitive to compressive creep,itsflow capacity could be greatly reduced or even shut offcompletely.5.2 The creep sensitivity of a candidate geosynthetic can betested at field-simulated normal stress and potentially shearstresses.5.3 This test method does not evaluate the effect of creep ofa geotextile filter or adjacent membrane.5.4 Compression creep as it relates to reduction in flowcapacity of a geosynthetic drainage product is manufacturerand product specific.For example,a 10%reduction in originalthickness of a geonet made by manufacturer A does notnecessarily equal the same reduction in flow capacity as a 10%reduction in thickness of the same or another type of geonetmade by manufacturer B.5.5 This creep data has is merit directly to the end user,because it can be easily interpreted to