1、Designation: D 2746 07Standard Test Method forStaining Tendency of Asphalt (Stain Index)1This standard is issued under the fixed designation D 2746; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe
2、r in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 exten
3、t of staining observed.1.2 This test method is applicable to asphalts having ring-and-ball softening points of 85C (185F) or greater.NOTE 1This test method may be modified for use with otherbituminous materials with softening points less than 85C (185F) byusing a different temperature than specified
4、 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
5、.1.3 The values stated in SI units are to be regarded as thestandard. The values in parentheses are for information only.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 sa
6、fety andhealth practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D36 Test Method for Softening Point of Bitumen (Ring-and-Ball Apparatus)D 140 Practice for Sampling Bituminous MaterialsE 2251 Specification for Liquid-in-Glass A
7、STM 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 c
8、ompared 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 (164 in.).4. Significance and Use4.1 This test method meas
9、ures 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 indic
10、ate 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 re
11、quired for use in the ring-and-ballsoftening point apparatus (see Fig. 1 (a) of Test Method D36).5.1.1 The inside diameter of the ring to be placed in contactwith the filter paper during the test is 16 mm (4064 in.).NOTE 2This test method depends on accurate measurement of diam-eter and precise alig
12、nment of the face and rim of the ring on a flat surface.Therefore, deformed rings must not be used.5.2 Pouring PlateA flat, smooth, brass plate approxi-mately 50 by 75 mm (2 by 3 in.).5.3 PaperFilter paper of the standard double acid-washedanalytical grade.35.3.1 The filter paper must be of sufficie
13、nt area to accom-modate the number of samples and the known materialarranged as described in 7.3.5.4 Support PlateA flat, clean, smooth metal plate ap-proximately 1.5 mm (116 in.) thick and area at least sufficient tosupport the size of filter paper being used.5.5 OvenA constant temperature oven cap
14、able of main-taining the test temperature of 80C (175F) within 61C(62F).1This test method is under the jurisdiction ofASTM Committee D08 on Roofingand Waterproofing and is the direct responsibility of Subcommittee D08.02 onPrepared Roofings, Shingles and Siding Materials.Current edition approved May
15、 1, 2007. Published May 2007. Originallyapproved in 1991. Last previous edition approved in 2002 as D 2746 97 (2002)e1.2For 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
16、to the standards Document Summary page onthe ASTM website.3The sole source of supply of the paper known to the committee at this time isWhatman No. 40 filter paper, available from laboratory supply and servicecompanies. If you are aware of alternative suppliers, please provide this informationto AST
17、M International Headquarters. Your comments will receive careful consid-eration at a meeting of the responsible technical committee,1which you may attend.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.6 ThermometerAn ASTM thermome
18、ter having a rangefrom 20 to 102C (5 to 215F), and conforming to therequirements forThermometer S12C (or S12F) as prescribed inSpecification E 2251. As an alternative, any other thermomet-ric device used shall be at least: (1) of equal accuracy to that ofthe thermometer specified in Specification E
19、2251,(2) capableof indicating temperature to within 1C (2F), and (3) stable towithin 1C (2F) for the duration of the exposure.5.7 Measuring RuleA steel rule graduated in 0.5 mm(64ths of an inch).5.7.1 Hole TemplateA metal or plastic template providedwith holes of diameter from 16 to 24 mm (4064 to60
20、64 in.) in0.5-mm (164-in.) increments may be used as an alternative tothe steel rule to measure the diameter of the stain circle afterthe test.6. Sampling6.1 Sample the material in accordance with Practice D 140.7. Procedure7.1 Melt the asphalt sample and pour into the preheatedbrass softening point
21、 ring, allow to cool, and trim off the excessasphalt from each face of the ring as described in Test MethodD36.7.1.1 It is important that the lower face and rim of the ring(16-mm (4064-in.) inside diameter) be clean and that the asphaltdisc completely fill the ring and be flush with the lower face.T
22、here should be no trace of any release agent which may havebeen used on the pouring plate (see Test Method D36)oneither the lower face of the ring or the asphalt.7.2 Place the filter paper on the flat support plate and put thefilled and trimmed softening point rings on the paper with the16-mm (4064-
23、in.) diameter asphalt disc face in contact with thepaper. Each ring should be no closer than 40 mm (1.5 in.) fromthe edge of the filter paper or from another ring.7.2.1 The known material (Note 3) must be placed on thesame piece of filter paper and support plate as the sample(s)being tested.NOTE 3Th
24、e “known” material for the purpose of this test is a materialwhose staining tendency is known to the investigator and which is used tocompare with the material being tested (see also Note 6).7.2.2 Identify each asphalt sample and known material byappropriately marking the filter paper in pencil near
25、 each ring.7.3 Place the entire assembly on the support plate in theoven, preheated to 80 6 1C (175 6 2F), and allow to remainat that temperature for 120 6 1h.7.4 Remove the assembly on the support plate from theoven and allow to cool to room temperature (about 24C(75F).7.5 Remove the ring and the a
26、sphalt disc from the filterpaper taking care to avoid tearing of the paper.7.6 Determine and record the average of three measure-ments, taken at about 120 apart, of the diameter of the stainedcircle on the filter paper expressed numerically in 0.4-mm units(64ths of an inch) to the nearest 0.4 mm (16
27、4 in.) using a steelrule.7.6.1 Alternatively, use the hole template and determine thediameter of the hole which best fits the stained circle on thefilter paper and record the result numerically in 0.4-mm units(64ths of an inch) to the nearest 0.4 mm (164 in.).8. Calculation and Interpretation of Res
28、ults8.1 Subtract the initial diameter of the asphalt disc ex-pressed numerically in 0.4-mm units (64ths of an inch), that is,40 from the average, or best fit, diameter of the stained circleon the filter paper expressed numerically in 0.4-mm units(64ths of an inch) to obtain the stain index.NOTE 4If
29、the dimensional measurements have been made in metricunits, the average diameter must be converted to inch units at this point inorder to compute the numerical value for stain index which is derivedfrom the diameter expressed numerically in 64ths of an inch.NOTE 5Example: If the average, or best fit
30、, diameter of the stainedcircle on the filter paper is 19.5 mm (4964 in.), then the stain in-dex=4940=9.8.2 Interpretation of ResultsThe following ranges of stainindex have been determined to represent the staining tendencyof asphalts used in the production of asphalt roofing shingles.Stain Index St
31、aining Tendency0to10 low10 to 20 moderateGreater than 20 highThe staining tendency in roofing products is strongly influ-enced by storage conditions especially temperature and time,by the pressure generated in stacked material from the mass ofmaterial in the overlying stack, and by the nature, amoun
32、t, anddistribution of backsurfacing material.9. Report9.1 Report the stain index value determined as in 8.1.10. Precision and Bias10.1 Results of two properly conducted tests by a singleoperator should not differ by more than two stain indexnumbers for asphalts with stain index of ten or less nor by
33、 morethan three stain index numbers for asphalts with stain indexgreater than ten.10.2 Results of two properly conducted tests on the samesample of asphalt between different laboratories should beconsidered suspect if they differ by more than four stain indexnumbers when one of the values is ten or
34、less, or if they differby more than six stain index numbers when both values aregreater than ten.10.3 A test should be considered suspect if the stain indexobtained for the known material differs by more than two fromthe expected value for materials with stain index of ten or less,or by more than th
35、ree for materials with stain index greaterthan 10.NOTE 6The major cause of bias error in this test method has beenfound to be inadvertent changes in the temperature of the test oven. Thisis the primary reason for suggesting comparison to a material with knownstaining tendency in the performance of t
36、he test.11. Keywords11.1 asphalt; stain index; stainingD2746072ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such
37、 patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited
38、 either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a f
39、air hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D2746073
