1、Designation: D7405 10aStandard Test Method forMultiple Stress Creep and Recovery (MSCR) of AsphaltBinder Using a Dynamic Shear Rheometer1, 2This standard is issued under the fixed designation D7405; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se 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 determination of percentrecovery and non-recoverable creep com
3、pliance of asphaltbinders by means of Multiple Stress Creep and Recovery(MSCR) testing. The MSCR test is conducted using theDynamic Shear Rheometer (DSR) at a specified temperature.1.2 This standard is appropriate for unaged material, mate-rial aged in accordance with Test Method D2872 (RTFO),materi
4、al aged in accordance with Practice D6521 (PAV), andmaterial aged in accordance with both Test Method D2872 andPractice D6521.NOTE 1The majority of development work on this test method wasperformed on material aged in accordance with Test Method D2872(RTFO).1.3 The percent recovery is intended to pr
5、ovide a means todetermine the presence of elastic response and stress depen-dence of polymer modified and unmodified asphalt binders.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 addre
6、ss 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:3C670 Practice f
7、or Preparing Precision and Bias Statementsfor Test Methods for Construction MaterialsD8 Terminology Relating to Materials for Roads and Pave-mentsD2872 Test Method for Effect of Heat and Air on a MovingFilm of Asphalt (Rolling Thin-Film Oven Test)D5801 Test Method for Toughness and Tenacity of Bitum
8、i-nous MaterialsD6084 Test Method for Elastic Recovery of BituminousMaterials by DuctilometerD6373 Specification for Performance Graded AsphaltBinderD6521 Practice for Accelerated Aging of Asphalt BinderUsing a Pressurized Aging Vessel (PAV)D7175 Test Method for Determining the Rheological Prop-erti
9、es of Asphalt Binder Using a Dynamic Shear Rheom-eter2.2 AASHTO Standards:4M 320 Specification for Performance-Graded AsphaltBinderTP 70 Test Method for Multiple Stress Creep and Recovery(MSCR) of Asphalt Binder Using a Dynamic ShearRheometer3. Terminology3.1 DefinitionsFor definitions of general te
10、rms used in thisstandard, refer to Terminology D8.3.1.1 creep and recovery, na standard rheological testprotocol whereby a specimen is subjected to a constant load fora fixed time period then allowed to recover at zero load for afixed time period.3.1.2 non-recoverable creep compliance (Jnr), nthe re
11、-sidual strain in a specimen after a creep and recovery cycledivided by the stress applied in kPa.4. Summary of Test Method4.1 This test method is used to determine the presence ofelastic response in an asphalt binder under shear creep andrecovery at two stress levels at a specified temperature. For
12、performance grade (PG) binders, the specified temperature willtypically be the PG grade upper temperature as determined inSpecification D6373 or AASHTO M 320. Sample preparationand apparatus are in accordance with Test Method D7175 using1This test method is under the jurisdiction of ASTM Committee D
13、04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.44 onRheological Tests.Current edition approved June 1, 2010. Published June 2010. Originallyapproved in 2008. Last previous edition approved in 2010 as D7405 10. DOI:10.1520/D7405-10A.2This test method is based on a
14、 work product of the Federal HighwayAdministration. A similar standard is published as AASHTO TP 70.3For 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 Do
15、cument Summary page onthe ASTM website.4Available from American Association of State Highway and TransportationOfficials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,http:/www.transportation.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken
16、, PA 19428-2959, United States.the 25 mm parallel plate geometry with a 1-mm gap setting.The sample is loaded at constant stress for 1 s then allowed torecover for 9 s. Ten creep and recovery cycles are run at 0.100kPa creep stress followed by ten at 3.200 kPa creep stress.5. Significance and Use5.1
17、 This test method is used to identify the presence ofelastic response in a binder and the change in elastic responseat two different stress levels. Non-recoverable creep compli-ance has been shown to be an indicator of the resistance of anasphalt binder to permanent deformation under repeated load.5
18、.2 This test method is also useful as a surrogate for othertest methods used to measure elasticity in asphalt binders suchas Test Method D5801 (Toughness and Tenacity), Test MethodD6084 (Elastic Recovery), and Test Method D7175 (DSRphase angle).6. Apparatus6.1 Dynamic Shear Rheometer (DSR)A dynamic
19、shearrheometer as described in theApparatus section of Test MethodD7175 and associated materials as described in the Materialssection of Test Method D7175. The rheometer shall run instress control mode.7. Preparation of Test Specimen7.1 Prepare the test specimen in accordance with the Pre-paring Tes
20、t Specimens section of Test Method D7175.NOTE 2This test may be run on a specimen previously tested indynamic shear in accordance with the Test Procedure section of TestMethod D7175.8. Procedure8.1 Allow the specimen to reach thermal equilibrium at thedesired test temperature in accordance with the
21、Test Proceduresection of Test Method D7175. If the specimen has previouslybeen tested in dynamic shear, allow the specimen to remainunloaded for at least one minute before starting the creep andrecovery test.8.2 Load the specimen at a constant creep stress of 0.100kPa for 1.00 second duration creep
22、and follow with a zerostress recovery of 9.00 second duration. The commanded fulltorque for each creep cycle shall be achieved within 0.003seconds from the start of the creep cycle as certified by theequipment manufacturer. Record the stress and strain at leastevery 0.10 seconds for the creep cycle
23、and at least every 0.45seconds for the recovery cycle on a running accumulated timesuch that, in addition to other data points, data points at 1.00 sand 10.00 s for each cycles local time are explicitly recorded.8.2.1 If the DSR does not record the strain at exactly 1.00and 10.00 seconds then the DS
24、R software shall extrapolateprior data to determine the strain value at the required time.Extrapolation data shall include a measured data point no morethan 0.05 s prior to the required time for a creep cycle, no morethan 0.30 s prior to the required time for a recovery cycle.NOTE 3If the creep and
25、recovery curves will be used for modeling,more frequent data points may be required.8.3 Allowing no rest period between cycles, repeat the creepand recovery cycle in 8.2 nine times for a total of ten cycles.8.4 Allowing no rest period following 8.3, repeat the tencreep and recovery cycles of 8.2 and
26、 8.3 utilizing a load of3.200 kPa.NOTE 4The total time required to complete the two-step creep andrecovery test is 200 seconds.8.5 For each of the twenty creep and recovery cycles recordthe following:8.5.1 Initial strain value at the beginning of the creepportion of each cycle. This strain shall be
27、denoted as 0.8.5.2 The strain value at the end of the creep portion (that is,after 1.0 s) of each cycle. This strain shall be denoted as c.8.5.3 The adjusted strain value at the end of creep portion(that is, after 1.0 s) of each cycle:15c 0(1)8.5.4 The strain value at the end of the recovery portion
28、(that is, after 10.0 s) of each cycle. This strain shall be denotedas r.8.5.5 The adjusted strain value at the end of recoveryportion (that is, after 10.0 s) of each cycle:105r 0(2)9. Calculation9.1 Using the results obtained in 8.5 determine the averagepercent recovery and non-recoverable creep com
29、pliance for theasphalt binder at creep stress levels of 0.100 kPa and 3.200 kPaas follows:9.1.1 For each of the ten cycles at a creep stress of 0.100kPa calculate the percent recovery, r(100, N), for N =1to10:r100, N! 51 10! 1001(3)9.1.2 For each of the ten cycles at a creep stress of 3.200kPa calcu
30、late the percent recovery, r(3200, N), for N =1to10:r3200, N! 51 10! 1001(4)9.1.3 Calculate average percent recovery at 0.100 kPa:R100 5 SUMr100, N! / 10 for N 5 1to10 (5)9.1.4 Calculate average percent recovery at 3.200 kPa:R3200 5 SUMr3200, N! / 10 for N 5 1to10 (6)9.1.5 Calculate percent differen
31、ce in recovery between0.100 kPa and 3.200 kPa:Rdiff5 R100 R3200! 100! / R100! (7)9.1.6 For each of the ten cycles at a creep stress of 0.100kPa calculate the non-recoverable creep compliance, Jnr(100,N), for N =1to10:Jnr100, N! 510100(8)9.1.7 For each of the ten cycles at a creep stress of 3.200kPa
32、calculate the non-recoverable creep compliance, Jnr(3200,N), for N =1to10:Jnr3200, N! 5103200(9)9.1.8 Calculate average non-recoverable creep complianceat 0.100 kPa:D7405 10a2Jnr100 5 SUMJnr100, N! / 10 for N 5 1 to 10 (10)9.1.9 Calculate average non-recoverable creep complianceat 3.200 kPa:Jnr3200
33、5 SUMJnr3200, N! / 10 for N 5 1to10 (11)9.1.10 Calculate percent difference in non-recoverable creepcompliance between 0.100 kPa and 3.200 kPa:Jnr2diff5 Jnr3200 Jnr100! 100! / Jnr100! (12)10. Report10.1 Report the following information:10.1.1 Sample identification;10.1.2 Test temperature, to the nea
34、rest 0.1C;10.1.3 Average percent recovery at 0.100 kPa, R100, to thenearest 0.1 %;10.1.4 Average percent recovery at 3.200 kPa, R3200, to thenearest 0.1 %;10.1.5 Percent difference between average recovery at 0.100kPa and 3.200 kPa, Rdiff, to the nearest 0.1 %;10.1.6 Non-recoverable creep compliance
35、 at 0.100 kPa,Jnr100, to three significant figures;10.1.7 Non-recoverable creep compliance at 3.200 kPa,Jnr3200, to three significant figures; and10.1.8 Percent difference between non-recoverable creepcompliance at 0.100 kPa and 3.200 kPa, Jnr-diff, to nearest0.1 %.11. Precision and Bias11.1 Precisi
36、onCriteria for judging the acceptability ofresults obtained by the Multiple-Stress Creep-Recovery(MSCR) method are given in Table 1.11.2 Single-Operator Precision (Repeatability)the figuresin Column 2 of Table 1 are the coefficients of variation thathave been found to be appropriate for the conditio
37、ns of testdescribed in Column 1. Two results obtained in the samelaboratory, by the same operator using the same equipment, inthe shortest practical period of time, should not be consideredsuspect unless the difference in the two results, expressed as apercent of their mean, exceeds the values given
38、 in Column 2.11.3 Multilaboratory Precision (Reproducibility) the fig-ures in Column 3 of Table 1 are the coefficients of variation thathave been found to be appropriate for the conditions of testdescribed in Column 1. Two results submitted by two differentoperators testing the same material in diff
39、erent laboratories,should not be considered suspect unless the difference in thetwo results, expressed as a percent of their mean, exceeds thevalues given in Column 3.11.4 BiasNo information can be presented on the bias ofthe procedure because no material having an accepted refer-ence value is avail
40、able.12. Keywords12.1 asphalt binder; creep and recovery; DSR; dynamicshear rheometer; elastic recovery; MSCR; non-recoverablecreep compliance; polymer modified asphaltTABLE 1 Estimated Repeatability and ReproducabilityNOTEThe precision estimates in this table are based on the analysis of test resul
41、ts from eight laboratories for eight asphalt binders. The analysisincluded five binder grades: PG 64-22, PG 64-34, PG 70-28, PG 70-34, and PG 76-22. Average Jnrresults varied from 0.061 to 2.498 kPa-1. AverageRecovery results varied from 0 to 88.3%.Condition Coefficient ofVariation (1s%)AAcceptable
42、Range ofTwo Test Results (d2s%)ASingle-Operator Precision:Recovery0.1kPa(%) 2.4% 6.7%Recovery3.2kPa(%) 3.0% 8.5%Jnr0.1kPa(kPa-1)1.00 4.6% 12.8%0.26 - 1.00 5.4% 15.2%0.10 - 0.25 13.7% 38.3%1.00 5.7% 16.0%0.26 - 1.00 5.5% 15.3%0.10 - 0.25 9.5% 26.6%1.00 9.1% 25.6%0.26 - 1.00 12.7% 35.6%0.10 - 0.25 16.
43、7% 46.8%1.00 7.9% 22.0%0.26 - 1.00 13.9% 39.0%0.10 - 0.25 15.2% 42.6% 0.10Bn/a n/aAThese limits represent the 1s% and d2s% limits described in Practice C670.BFor Jnrvalues below 0.1 kPa-1high variability is likely due to the very low strain values that are measured. If an asphalt binder has a Jnrval
44、ue below 0.1 kPa-1at aspecified temperature, then consideration should be given to testing at a temperature that is 6C higher.D7405 10a3ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this stan
45、dard are expressly advised that determination of the validity of any such 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 and
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47、hich you may attend. If you feel that your comments have not received a fair 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
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