ASTM_D_2746_-_D_2746M_-_18.pdf

Designation:D2746/D2746M18Standard Test Method forStaining Tendency of Asphalt(Stain Index)1This standard is issued under the fixed designation D2746/D2746M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the stain-ing tendency of asphalt and the assignment of a stain indexproportional to the extent of staining observed.1.2 This test method is applicable to asphalts having ring-and-ball softening points of 85C 185F or greater.NOTE1This test method may be modified for use with otherbituminous materials with softening points less than 85C 185F byusing a different temperature than specified in Section 7 by agreement ofthe interested parties.The report of results from such a test may cite thismethod but must clearly state the temperature employed in the exceptionand acknowledge that the interpretation of results in Section 9 and theprecision and bias stated in Section 10 may not apply.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standard.1.4 This standard does not purport to address the safetyconcerns,if any,associated with its use.It is the responsibilityof the user of this standard to establish appropriate safety,health,and environmental practices and determine the appli-cability 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:2D36/D36M Test Method for Softening Point of Bitumen(Ring-and-Ball Apparatus)D140/D140M Practice for Sampling Asphalt MaterialsE230/E230M Specification for Temperature-ElectromotiveForce(emf)Tables for Standardized ThermocouplesE1137/E1137M Specification for Industrial Platinum Resis-tance ThermometersE2251 Specification for Liquid-in-Glass ASTM Thermom-eters with Low-Hazard Precision Liquids3.Summary of Test Method3.1 A horizontal disc of asphalt,cast in a brass retainingring,is placed on a sheet of filter paper supported on a flat plateand heated at 80C 175F for 120 h.The diameter of theresulting stained circle on the paper is compared to the insidediameter of the brass ring to determine the staining character-istic of the asphalt.The stain index is the difference betweenthe diameter of the stained circle and the initial disc diametermeasured to the nearest 0.5 mm 164in.4.Significance and Use4.1 This test method measures the tendency for oil compo-nents to separate spontaneously from asphalt.The separation ofoil components can cause staining in asphalt roofing productsand adjacent materials in storage and use.4.2 The stain index is related to the thermal stability of theasphalt.Higher stain index values indicate lower stability andgreater tendency for staining.4.3 Use this procedure to determine the staining tendency ofasphalt and to compare the results against a material for whichthe staining tendency is known.5.Apparatus5.1 RingsSquare shouldered brass retaining rings con-forming to the dimensions required for use in the ring-and-ballsoftening point apparatus(see Fig.1(a)of Test MethodD36/D36M).5.1.1 The inside diameter of the ring to be placed in contactwith the filter paper during the test is 16 mm 4064in.NOTE2This test method depends on accurate measurement ofdiameter and precise alignment of the face and rim of the ring on a flatsurface.Therefore,deformed rings must not be used.1This test method is under the jurisdiction ofASTM Committee D08 on Roofingand Waterproofing and is the direct responsibility of Subcommittee D08.02 onSteep Roofing Products and Assemblies.Current edition approved Nov.1,2018.Published December 2018.Originallyapproved in 1991.Last previous edition approved in 2013 as D2746 07(2013).DOI:10.1520/D2746_D2746M-18.2For 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 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 Recommen