ASTM D7405-20

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it 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 version
of the standard as published by ASTM is to be considered the official document.
Designation: D7405 − 15 D7405 − 20
Standard Test Method for
Multiple Stress Creep and Recovery (MSCR) of Asphalt
1,2
Binder Using a Dynamic Shear Rheometer
This standard is issued under the fixed designation D7405; 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 Recoverymultiple stress creep and recovery (MSCR) testing. The MSCR test is conducted
using the Dynamic Shear Rheometerdynamic 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),(RTFOT),
material aged in accordance with Practice D6521 (PAV), and material aged in accordance with both Test Method D2872 and
Practice D6521.
NOTE 1—The majority of development work on this test method was performed on material aged in accordance with Test Method D2872
(RTFO).(RTFOT).
1.3 The percent recovery is intended to provide a means to determine the presence of elastic response and stress dependence
of polymer modified 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 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered as requirements of the 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C670 Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
D8 Terminology Relating to Materials for Roads and Pavements
D2872 Test Method for Effect of Heat and Air on a Moving Film of Asphalt (Rolling Thin-Film Oven Test)
D3666 Specification for Minimum Requirements for Agencies Testing and Inspecting Road and Paving Materials
D5801 Test Method for Toughness and Tenacity of Asphalt Materials
D6084D6084/D6084M Test Method for Elastic Recovery of Asphalt Materials by Ductilometer
D6373 Specification for Performance Graded Asphalt Binder
D6521 Practice for Accelerated Aging of Asphalt Binder Using a Pressurized Aging Vessel (PAV)
D7175 Test Method for Determining the Rheological Properties of Asphalt Binder Using a Dynamic Shear Rheometer
This test method is under the jurisdiction of ASTM Committee D04 on Road and Paving Materials and is the direct responsibility of Subcommittee D04.44 on Rheological
Tests.
Current edition approved Dec. 1, 2015March 1, 2020. Published January 2016March 2020. Originally approved in 2008. Last previous edition approved in 20102015 as
D7405 – 10a.D7405 – 15. DOI: 10.1520/D7405-15.10.1520/D7405-20.
This test method is based on a work product of the Federal Highway Administration. A similar standard is published as AASHTO TP 70.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM 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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7405 − 20
2.2 AASHTO Standards:
M 332 Specification for Performance-Graded Asphalt Binder Using Multiple Stress Creep Recovery (MSCR) Test
T 350 Method of Test for Multiple Stress Creep Recovery (MSCR) Test of Asphalt Binder Using a Dynamic Shear Rheometer
(DSR)
3. Terminology
3.1 Definitions—For definitions of general terms used in this standard, refer to Terminology D8.
3.2 Definitions—Definitions of Terms Specific to This Standard:For definitions of general terms used in this standard, refer to
Terminology D8.
3.2.1 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.
3.2.2 non-recoverable creep compliance (J ), n—the residual strain in a specimen after a creep and recovery cycle divided by
nr
the stress applied in kPa.
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
PG high temperature without grade bumping as determined in Specification D6373 or AASHTO M 332. Sample preparation and
apparatus are in accordance with Test Method D7175 using the 25-mm 25 mm parallel plate geometry with a 1-mm 1 mm gap
setting. The sample is loaded at constant stress for 1 s then allowed to recover for 9 s. Twenty creep and recovery cycles are run
at 0.100 kPa creep stress followed by ten creep and recovery cycles at 3.200 kPa 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 D5801 (Toughness(toughness and Tenacity),tenacity), Test Method D6084D6084/D6084M (Elastic Recovery),
(elastic recovery), and Test Method D7175 (DSR phase angle).
NOTE 2—The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the
capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of Specification D3666 are generally considered capable
of competent and objective testing, sampling, inspection, etc. Users of this standard are cautioned that compliance with Specification D3666 alone does
not completely ensure reliable results. Reliable results depend on many factors; following the suggestions of Specification D3666 or some similar
acceptable guideline provides a means of evaluating and controlling some of those factors.
6. Apparatus
6.1 Dynamic Shear Rheometer (DSR)—A dynamic shear rheometer as described in the Apparatus section of Test Method D7175
and associated materials as described in the Materials section of Test Method D7175. The rheometer shall run in stress control
mode. The plate radius parameter shall be set at 100 %.
7. Preparation of Test Specimen
7.1 Prepare the test specimen in accordance with the Preparing Test Specimens section of Test Method D7175.
NOTE 3—This test may be run on a specimen previously tested in dynamic shear in accordance with the Test Procedure section of Test Method D7175.
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 D7175. If the specimen has previously been tested in dynamic shear, allow the specimen to remain unloaded
for at least 1 min before starting the creep and recovery test.
8.2 Creep and Recovery Cycle—Load the specimen at a constant creep stress for 1.00 s duration creep and follow with a zero
stress recovery of 9.00 s duration. The commanded full torque for each creep cycle shall be achieved within 0.003 s from the start
of the creep cycle as certified by the equipment manufacturer. Record the stress and strain at least every 0.10 s for the creep cycle
and at least every 0.45 s for the recovery cycle on a running accumulated time such that, in addition to other data points, data points
at 1.00 s and 10.00 s for each cycle’s local time are explicitly recorded. If the DSR does not record the strain at exactly 1.00 and
Available from American Association of State Highway and Transportation Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,
http://www.transportation.org.
D7405 − 20
10.00 s then the DSR software shall extrapolate prior data to determine the strain value at the required time. Extrapolation data
shall include a measured data point no more than 0.10 s prior to the required time for a creep cycle, no more than 0.50 s prior to
the required time for a recovery cycle.
NOTE 4—If 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, perform 20 creep and recovery cycles at a creep stress of 0.100 kPa. The first 10ten
cycles are for conditioni
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