ASTM_D_6682_-_08.pdf

Designation:D668208Standard Test Method forMeasuring Shear Stresses of Powders Using PeschlRotational Split Level Shear Tester1This standard is issued under the fixed designation D6682;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.Scope*1.1 This test method is applied to the measurement of themechanical properties of powders as a function of normalstress.1.2 This apparatus is suitable measuring the properties ofpowders and other bulk solids,up to a particle size of 5000micron.1.3 This method comprises four different test procedures forthe determination of powder mechanical properties:1.3.1 Test AMeasurement of INTERNAL FRICTION as afunction of normal stress.1.3.2 Test BMeasurement of WALL FRICTION as afunction of normal stress.1.3.3 Test CMeasurement of BULK DENSITY as a func-tion of normal stress and time.1.3.4 Test DMeasurement of DEGRADATION as a func-tion of normal stress.1.4 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.4.1 The procedures used to specify how data are collected/recorded or calculated in this standard are regarded as theindustry standard.In addition,they are representative of thesignificant digits that generally should be retained.The proce-dures used do not consider material variation,purpose forobtaining the data,special purpose studies,or any consider-ations for the users objectives,and it is common practice toincrease or reduce significant digits of reported data to becommensurate with these considerations.It is beyond the scopeof this standard to consider significant digits used in analysismethods for engineering design.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 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:2D653 Terminology Relating to Soil,Rock,and ContainedFluidsD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD6026 Practice for Using Significant Digits in GeotechnicalData3.Terminology3.1 For definitions of technical terms in this standard,referto Terminology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 adhesionshear stress between the wall coupon andpowder at a normal stress of zero.3.2.2 consolidation normal stressthe maximal normalstress applied to the specimen for executing an yield locus.3.2.3 consolidation stepshearing repeated under the con-solidation normal stress until the shear stress reaches a maxi-mum mvalue followed by a steady state value s.This step isperformed before each shear step.3.2.4 degradationchange of particle size as result ofshearing.3.2.5 dynamic wall frictioncalculated from the measurednormal stress and the steady state shear stress after certainshearing.3.2.6 dynamic yield locusline calculated from measuredvalues of normal stress and steady values of the shear stress.1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.24 on Characterizationand Handling of Powders and Bulk Solids.Current edition approved Oct.1,2008.Published October 2008.Originallyapproved in 2001.Last previous edition approved in 2006 as D6682 01(2006).DOI:10.1520/D6682-08.2For 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.7 peak shear stress(m)maximum shear stress at thebeginning of yield-at the transition between elastic and plasticdeformation.3.2.8 pre-consolidation normal stress(np)normal stressapplied during the first part of the test in order to densify thespecimen.3.2.9 shear stepshear after the consolidation step,per-formed under the normal stress which is equal to or lower thanthe consolidation normal stress,until the shear stress reachesthe peak value followed by a steady state value s.3.2.10 split levellevel between the bottom and top coverof the shear cell defined by the transition of the cell base andring where in the specimen the shear plane occurs.3.2.11 static wall frictioncalculated from the measurednormal stress and the maximum shear s