ASTM_D_7312_-_10.pdf

Designation:D731210Standard Test Method forDetermining the Permanent Shear Strain and ComplexShear Modulus of Asphalt Mixtures Using the SuperpaveShear Tester(SST)1This standard is issued under the fixed designation D7312;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 standard provides performance-related test proce-dures for the determination of stiffness complex shear modulusand permanent shear strain of asphalt mixtures using theSuperpave Shear Tester(SST).This standard is applicable tothe testing and analysis of modified and unmodified asphaltmixtures.1.2 This standard is applicable to specimens prepared in alaboratory or cored from a pavement for post-constructionanalysis.It is intended for use with specimens having thefollowing minimum dimensions:Nominal Maximum AggregateSize in Asphalt MixtureSpecimenDiameterSpecimenHeight19 mm150 mm50 mm12.5 mm,9.5 mm,4.75 mm150 mm38 mmNOTE1Nominal maximum aggregate size is defined in AASHTOR35 as one sieve larger than the first sieve to retain more than 10%of thetotal aggregate.Asphalt mixtures with a nominal maximum aggregate sizegreater than 19 mm can be tested using this procedure,but it is notrecommended.The larger aggregate sizes may significantly interfere withthe material response,thereby affecting the repeatability of the test.NOTE2The SST shall accommodate test specimens of 150 mm indiameter and 50 mm in height.The specimen height of 50 mm ispreferred,but may not be available in roadway cores where layerthickness may be less.If the specimen height is less than 50 mm,useplaten to platen fixturing(Linear Variable Differential Transformers(LVDTs)or extensometers).Specimen heights less than 38 mm cannot betested because of equipment constraints.NOTE3The diameter-to-height ratio for shear test specimens shouldbe 3:1 or greater.This effectively eliminates the use of 100 mm diameterspecimens(because of minimum height requirement for testing discussedin Note 2).1.3 The between laboratory reproducibility of this testmethod has not been determined,therefore this standard shouldnot be used for acceptance or rejection of a material forpurchasing purposes.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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:2D75 Practice for Sampling AggregatesD140 Practice for Sampling Bituminous MaterialsD979 Practice for Sampling Bituminous Paving MixturesD2041 Test Method for Theoretical Maximum SpecificGravity and Density of Bituminous Paving MixturesD2726 Test Method for Bulk Specific Gravity and Densityof Non-Absorptive Compacted Bituminous MixturesD3203 Test Method for Percent Air Voids in CompactedDense and Open Bituminous Paving MixturesD3549 Test Method for Thickness or Height of CompactedBituminous Paving Mixture SpecimensD5361 Practice for Sampling Compacted Bituminous Mix-tures for Laboratory TestingD6752 Test Method for Bulk Specific Gravity and Densityof Compacted Bituminous Mixtures Using AutomaticVacuum Sealing MethodD6857 Test Method for Maximum Specific Gravity andDensity of Bituminous Paving Mixtures Using AutomaticVacuum Sealing MethodD6925 Test Method for Preparation and Determination ofthe Relative Density of Asphalt Mix Specimens by Meansof the Superpave Gyratory CompactorE1 Specification for ASTM Liquid-in-Glass ThermometersE4 Practices for Force Verification of Testing Machines1This test method is under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.26 onFundamental/Mechanistic Tests.Current edition approved Dec.1,2010.Published December 2010.Originallyapproved 2007.Last published in 2007 as D731207.DOI:10.1520/D7312-10.2For 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 2.2 AASHTO Standards:3AASHTO R35 Superpave Volumetric Design for Hot MixAsphalt(HMA)AASHTO R30 Short and Long Term Aging of Hot MixAsphalt(HMA)3.Terminology3.1 Definitions:3.1.1 complex shear modulusa complex number that de-fines the relationship between shear stress and strain for alinear viscoelastic material,G*.3.1.2 permanent shear strainthe non-recoverable shearstrain resulting from a sh