ASTM_D_8225_-_19.pdf

Designation:D822519Standard Test Method forDetermination of Cracking Tolerance Index of AsphaltMixture Using the Indirect Tensile Cracking Test atIntermediate Temperature1This standard is issued under the fixed designation D8225;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 covers the procedures for preparing,testing,and measuring asphalt mixture cracking resistanceusing cylindrical laboratory-prepared asphalt mix samples orpavement cores.Testing temperatures are selected from thelong-term pavement performance(LTPP)database intermedi-ate temperatures.The test method describes the determinationof the cracking tolerance index,CTIndex,and other parametersdetermined from the load-displacement curve.These param-eters can be used to evaluate the resistance of asphalt mixturesto cracking.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 The text of this standard references notes and footnoteswhich provide explanatory material.These notes and footnotes(excluding those in tables and figures)shall not be consideredas requirements of the standard.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D8 Terminology Relating to Materials for Roads and Pave-mentsD3203/D3203M Test Method for Percent Air Voids in Com-pacted Asphalt MixturesD3666 Specification for Minimum Requirements for Agen-cies Testing and Inspecting Road and Paving MaterialsD6373 Specification for Performance Graded AsphaltBinderD6925 Test Method for Preparation and Determination ofthe Relative Density of Asphalt Mix Specimens by Meansof the Superpave Gyratory Compactor2.2 AASHTO Standards:3R 30 Practice for Mixture Conditioning of Hot Mix Asphalt(HMA)M 320 Specification for Performance-Graded AsphaltBinderM 332 Specification for Performance-Graded AsphaltBinder Using Multiple Stress Creep Recovery(MSCR)Test3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard,refer toTerminology D8.3.2 Definitions of Terms Specific to This Standard:3.2.1 CTIndex,ncracking tolerance index,value used toevaluate mixture resistance to cracking.3.2.2 Gf,nfailure energy(Joules/m2)required to induce aunit surface area of a crack and calculated as the work of1This 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 April 1,2019.Published April 2019.Originallyapproved in 2019.DOI:10.1520/D8225-19.2For 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.3Available from American Association of State Highway and TransportationOfficials(AASHTO),444 N.Capitol St.,NW,Suite 249,Washington,DC 20001,http:/www.transportation.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 failure divided by specimen diameter(150 6 2 mm)andnormalized thickness of 62 mm.3.2.3 l65,ndisplacement(mm)corresponding to 65%ofthe peak load at the post-peak stage.See Fig.1.3.2.4 l75,ndisplacement(mm)corresponding to 75%ofthe peak load at the post-peak stage.See Fig.1.3.2.5 l85,ndisplacement(mm)corresponding to 85%ofthe peak load at the post-peak stage.See Fig.1.3.2.6|m75|,nslope(N/m)calculated as|P852P65l852l65|using alinear regression with all data points between P85(l85)and P65(l65).See Fig.1.3.2.7 P65,n65%of the peak load(kN)at the post-peakstage.See Fig.1.3.2.8 P75,n75%of the peak load(kN)at the post-peakstage.See Fig.1.3.2.9 P85,n85%of the peak load(kN)at the post-peakstage.See Fig.1.3.2.10 Wf,nwork of failure(Joules)calculated as the areaunder the loa