1、Designation: D7405 10aD7405 15Standard 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
2、 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 determination of percent recovery and non-recoverable c
3、reep compliance of asphalt binders bymeans of Multiple Stress Creep and Recovery (MSCR) testing. The MSCR test is conducted using the Dynamic Shear Rheometer(DSR) at a specified temperature.1.2 This standard is appropriate for unaged material, material aged in accordance with Test Method D2872 (RTFO
4、), materialaged in accordance with Practice D6521 (PAV), and material aged in accordance with both Test Method D2872 and PracticeD6521.NOTE 1The majority of development work on this test method was performed on material aged in accordance with Test Method D2872 (RTFO).1.3 The percent recovery is int
5、ended to provide a means to determine the presence of elastic response and stress dependenceof polymer modified and unmodified asphalt binders.1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.5 This standard does not purp
6、ort to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:3C670
7、Practice for Preparing Precision and Bias Statements for Test Methods for Construction MaterialsD8 Terminology Relating to Materials for Roads and PavementsD2872 Test Method for Effect of Heat and Air on a Moving Film of Asphalt (Rolling Thin-Film Oven Test)D5801 Test Method for Toughness and Tenaci
8、ty of Bituminous MaterialsD6084 Test Method for Elastic Recovery of Asphalt Materials by DuctilometerD6373 Specification for Performance Graded Asphalt BinderD6521 Practice for Accelerated Aging of Asphalt Binder Using a Pressurized Aging Vessel (PAV)D7175 Test Method for Determining the Rheological
9、 Properties of Asphalt Binder Using a Dynamic Shear Rheometer2.2 AASHTO Standards:4M 320M 332 Specification for Performance-Graded Asphalt Binder Using Multiple Stress Creep Recovery (MSCR) TestTP70T350 Test Method ofTest for Multiple Stress Creep and Recovery (MSCR)Test ofAsphalt Binder Using a Dyn
10、amic ShearRheometer (DSR)3. Terminology3.1 DefinitionsFor definitions of general terms used in this standard, refer to Terminology D8.1 This test method is under the jurisdiction ofASTM Committee D04 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.44 on RheologicalT
11、ests.Current edition approved June 1, 2010Dec. 1, 2015. Published June 2010January 2016. Originally approved in 2008. Last previous edition approved in 2010 asD7405 10.D7405 10a. DOI: 10.1520/D7405-10A.10.1520/D7405-15.2 This test method is based on a work product of the Federal Highway Administrati
12、on. A similar standard is published as AASHTO TP 70.3 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.4 Availab
13、le from American Association of State Highway and Transportation Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,http:/www.transportation.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes h
14、ave been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official d
15、ocument.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.1 creep and recovery, na standard rheological test protocol whereby a specimen is subjected to a constant load for a fixedtime period then allowed to recover at zero load for
16、 a fixed time period.3.1.2 non-recoverable creep compliance (Jnr),nthe residual strain in a specimen after a creep and recovery cycle divided bythe stress applied in kPa.4. Summary of Test Method4.1 This test method is used to determine the presence of elastic response in an asphalt binder under she
17、ar creep and recoveryat two stress levels at a specified temperature. For performance grade (PG) binders, the specified temperature will typically be thePG grade upper temperature high temperature without grade bumping as determined in Specification D6373 or AASHTOM 320.M 332. Sample preparation and
18、 apparatus are in accordance with Test Method D7175 using the 25 mm 25-mm parallel plategeometry with a 1-mm gap setting. The sample is loaded at constant stress for 1 s then allowed to recover for 9 s. TenTwenty creepand recovery cycles are run at 0.100 kPa creep stress followed by ten creep and re
19、covery cycles at 3.200 kPa creep stress.5. Significance and Use5.1 This test method is used to identify the presence of elastic response in a binder and the change in elastic response at twodifferent stress levels. Non-recoverable creep compliance has been shown to be an indicator of the resistance
20、of an asphalt binderto permanent deformation under repeated load.5.2 This test method is also useful as a surrogate for other test methods used to measure elasticity in asphalt binders such asTest Method D5801 (Toughness and Tenacity), Test Method D6084 (Elastic Recovery), and Test Method D7175 (DSR
21、 phaseangle).6. Apparatus6.1 Dynamic Shear Rheometer (DSR)Adynamic shear rheometer as described in theApparatus section of Test Method D7175and associated materials as described in the Materials section of Test Method D7175. The rheometer shall run in stress controlmode.7. Preparation of Test Specim
22、en7.1 Prepare the test specimen in accordance with the Preparing Test Specimens section of Test Method D7175.NOTE 2This test may be run on a specimen previously tested in dynamic shear in accordance with the Test Procedure section of Test Method D7175.8. Procedure8.1 Allow the specimen to reach ther
23、mal equilibrium at the desired test temperature in accordance with the Test Proceduresection ofTest Method D7175. If the specimen has previously been tested in dynamic shear, allow the specimen to remain unloadedfor at least one minute1 min before starting the creep and recovery test.8.2 Creep and R
24、ecovery CycleLoad the specimen at a constant creep stress of 0.100 kPa for 1.00 seconds duration creep andfollow with a zero stress recovery of 9.00 seconds duration. The commanded full torque for each creep cycle shall be achievedwithin 0.003 secondss from the start of the creep cycle as certified
25、by the equipment manufacturer. Record the stress and strainat least every 0.10 secondss for the creep cycle and at least every 0.45 secondss for the recovery cycle on a running accumulatedtime such that, in addition to other data points, data points at 1.00 s and 10.00 s for each cycles local time a
26、re explicitly recorded.If the DSR does not record the strain at exactly 1.00 and 10.00 s then the DSR software shall extrapolate prior data to determinethe strain value at the required time. Extrapolation data shall include a measured data point no more than 0.10 s prior to the requiredtime for a cr
27、eep cycle, no more than 0.50 s prior to the required time for a recovery cycle.8.2.1 If the DSR does not record the strain at exactly 1.00 and 10.00 seconds then the DSR software shall extrapolate prior datato determine the strain value at the required time. Extrapolation data shall include a measur
28、ed data point no more than 0.05 s priorto the required time for a creep cycle, no more than 0.30 s prior to the required time for a recovery cycle.NOTE 3If the creep and recovery curves will be used for modeling, more frequent data points may be required.8.3 Allowing no rest period between cycles, r
29、epeat theperform 20 creep and recovery cycle incycles at 8.2 nine times for a totalof ten cycles.a creep stress of 0.100 kPa. The first 10 cycles are for conditioning the specimen. The second 10 cycles are for datacollection and analysis.8.4 Allowing no rest period following 8.3, repeat the ten and
30、no rest period between cycles, perform 10 creep and recoverycycles of at a creep stress of 3.200 kPa. The total time required to complete 8.28.3 and 8.38.4 utilizing a load of 3.200 kPa.is 300s.NOTE 4The total time required to complete the two-step creep and recovery test is 200 seconds.8.5 For each
31、 of the twenty creep and recovery cycles last 10 cycles at the 0.100 kPa stress level and the 10 cycles at the 3.200kPa stress level record the following:8.5.1 Initial strain value at the beginning of the creep portion of each cycle. This strain shall be denoted as 0.D7405 1528.5.2 The strain value
32、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 the creep portion (that is, after 1.0 s) of each cycle:cycle, 1, calculated as:15c 20 (1)8.5.4 The strain value at the end of the recovery portion (th
33、at is, after 10.0 s) of each cycle. This strain shall be denoted as r.8.5.5 The adjusted strain value at the end of the recovery portion (that is, after 10.0 s) of each cycle:cycle, 10, calculated as:105r 20 (2)9. Calculation9.1 Using the results obtained in 8.5 determine the average percent recover
34、y and non-recoverable creep compliance for theasphalt binder at creep stress levels of 0.100 kPa and 3.200 kPa as follows:9.1.1 For each of the ten last 10 cycles at a creep stress of 0.100 kPa calculate the percent recovery, r(100,(0.1, N), for N =1 to 10:r100,N! 51210!1001(3)r0.1,N! 51210!1001(3)9
35、.1.1.1 If r(0.1, N) 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 16.7% 46.8%1.00 7.9% 22.0%0.26 - 1.00 13.9% 39.0%0.10 - 0.25 15.2% 42.6% 0.10B n/a n/aAThese These limits repre
36、sent the 1s% and d2s% limits described in Practice C670.BFor For Jnr values below 0.1 kPa-11 high variability is likely due to the very low strain values that are measured. If an asphalt binder has a Jnr value below 0.1 kPa-11at a specified temperature, then consideration should be given to testing at a temperature that is 6C higher.D7405 155
