ASTM D7405-08

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Designation:D7405–08
Standard Test Method for
Multiple Stress Creep and Recovery (MSCR) of Asphalt
Binder Using a Dynamic Shear Rheometer
This standard is issued under the fixed designation D 7405; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the determination of percent recovery and non-recoverable creep compliance of asphalt binders by
means 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 D 2872 (RTFO), material
aged in accordance with Practice D 6521 (PAV), and material aged in accordance with both Test Method D 2872 and Practice
D 6521.
NOTE 1—The majority of development work on this test method was performed on material aged in accordance with Test Method D 2872 (RTFO).
1.3 The percent recovery is intended to provide a means to determine the presence of elastic response and stress dependence
of polymer modified and unmodified asphalt binders.
1.4 Aprecision and bias statement for this standard has not been developed at this time. Therefore, this standard should not be
used for acceptance or rejection of a material for purchasing purposes.
1.5 The values stated in SI units are to be considered standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
C 670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
D 8 Terminology Relating to Materials for Roads and Pavements
D 2872 Test Method for Effect of Heat and Air on a Moving Film of Asphalt (Rolling Thin-Film Oven Test)
D 5801 Test Method for Toughness and Tenacity of Bituminous Materials
D 6084 Test Method for Elastic Recovery of Bituminous Materials by Ductilometer
D 6373 Specification for Performance Graded Asphalt Binder
D 6521 Practice for Accelerated Aging of Asphalt Binder Using a Pressurized Aging Vessel (PAV)
D 7175 Test Method for Determining the Rheological Properties of Asphalt Binder Using a Dynamic Shear Rheometer
3. Terminology
3.1 Definitions—For definitions of general terms used in this standard, refer to Terminology D 8.
3.1.1 creep and recovery, n—a standard rheological test protocol whereby a specimen is subjected to a constant load for a fixed
time period then allowed to recover at zero load for a fixed time period.
3.1.2 non-recoverable creep compliance (J ), n—the residual strain in a specimen after a creep and recovery cycle divided by
nr
the stress applied.
4. Summary of Test Method
4.1 This test method is used to determine the presence of elastic response in an asphalt binder under shear creep and recovery
at two stress levels at a specified temperature. For performance grade (PG) binders, the specified temperature will typically be the
ThistestmethodisunderthejurisdictionofASTMCommitteeD04onRoadandPavingMaterialsandisthedirectresponsibilityofSubcommitteeD04.44onRheological
Tests.
Current edition approved Feb. 1, 2008. Published February 2008.
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
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D7405–08
PG grade upper temperature as determined in Specification D 6373. Sample preparation and apparatus are in accordance with Test
Method D 7175 using the 25 mm parallel plate geometry with a 1-mm gap setting. The sample is loaded at constant stress for 1
s then allowed to recover for 9 s. Ten creep and recovery cycles are run at 100 Pa creep stress followed by ten at 3200 Pa creep
stress.
5. Significance and Use
5.1 This test method is used to identify the presence of elastic response in a binder and the change in elastic response at two
different stress levels. Non-recoverable creep compliance has been shown to be an indicator of the resistance of an asphalt binder
to 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 as
Test Method D 5801 (Toughness and Tenacity), Test Method D 6084 (Elastic Recovery) and Test Method D 7175 (DSR phase
angle).
6. Apparatus
6.1 Dynamic Shear Rheometer (DSR)— A dynamic shear rheometer as described in the Apparatus section of Test Method
D 7175 and associated materials as described in the Materials section of Test Method D 7175. The rheometer shall run in stress
control mode.
7. Preparation of Test Specimen
7.1 Prepare the test specimen in accordance with the Preparing Test Specimens section of Test Method D 7175.
NOTE 2—This test may be run on a specimen previously tested in dynamic shear in accordance with theTest Procedure section ofTest Method D 7175.
8. Procedure
8.1 Allow the specimen to reach thermal equilibrium at the desired test temperature in accordance with the Test Procedure
section of Test Method D 7175. If the specimen has previously been tested in dynamic shear, allow the specimen to remain
unloaded for at least one minute before starting the creep and recovery test.
8.2 Load the specimen at a constant creep stress of 100 Pa for 1.00 second duration
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