ASTM D8360-22

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.
Designation: D8360 − 22
Standard Test Method for
Determination of Rutting Tolerance Index of Asphalt Mixture
Using the Ideal Rutting Test
This standard is issued under the fixed designation D8360; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method covers the procedures for preparing,
D8Terminology Relating to Materials for Roads and Pave-
testing, and measuring asphalt mixture rutting resistance at
ments
high temperatures using cylindrical laboratory-prepared as-
D979/D979MPractice for Sampling Bituminous Paving
phalt mix samples or pavement cores. The test method de-
Mixtures
scribes the determination of the rutting tolerance index,
D3203/D3203MTest Method for PercentAirVoids in Com-
RT , and other parameters determined from the load-
Index
pacted Asphalt Mixtures
displacement curve. These parameters can be used to evaluate
D3666Specification for Minimum Requirements for Agen-
the resistance of asphalt mixtures to rutting.
cies Testing and Inspecting Road and Paving Materials
1.2 The values stated in SI units are to be regarded as
D6925Test Method for Preparation and Determination of
standard. No other units of measurement are included in this
theRelativeDensityofAsphaltMixSpecimensbyMeans
standard.
of the Superpave Gyratory Compactor
D6926Practice for Preparation of Asphalt Mixture Speci-
1.3 The text of this standard references notes and footnotes
whichprovideexplanatorymaterial.Thesenotesandfootnotes mens Using Marshall Apparatus
D6927Test Method for Marshall Stability and Flow of
(excluding those in tables and figures) shall not be considered
as requirements of the standard. Asphalt Mixtures
2.2 AASHTO Standards:
1.4 The within-laboratory repeatability standard deviation
R30Practice for Mixture Conditioning of Hot MixAsphalt
of rutting tolerance index has been determined to be 2.42,
(HMA)
basedontwolabs,30testreplicates,andtendifferentsamples.
T 324Standard Method of Test for Hamburg Wheel-Track
The between-laboratory reproducibility of this test method is
Testing of Compacted Asphalt Mixtures
being determined and will be available on or before December
T 340Standard Method of Test for Determining Rutting
31, 2026. Therefore, this standard should not be used for
Susceptibility of Hot Mix Asphalt (HMA) Using the
acceptance or rejection of a material for purchasing purpose.
Asphalt Pavement Analyzer (APA)
1.5 This standard does not purport to address all of the
T 378Standard Method of Test for Determining the Dy-
safety concerns, if any, associated with its use. It is the
namic Modulus and Flow Number for Asphalt Mixtures
responsibility of the user of this standard to establish appro-
Using the Asphalt Mixture Performance Tester (AMPT)
priate safety, health, and environmental practices and deter-
TP 116Standard Method of Test for Rutting Resistance of
mine the applicability of regulatory limitations prior to use.
Asphalt Mixtures Using Incremental Repeated Load Per-
1.6 This international standard was developed in accor- manent Deformation (iRLPD)
dance with internationally recognized principles on standard-
3. Terminology
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
3.1 Definitions—For definitions of terms used in this
mendations issued by the World Trade Organization Technical
standard, refer to Terminology D8.
Barriers to Trade (TBT) Committee.
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
This test method is under the jurisdiction of ASTM Committee D04 on Road Standards volume information, refer to the standard’s Document Summary page on
and Paving Materials and is the direct responsibility of Subcommittee D04.26 on the ASTM website.
Fundamental/Mechanistic Tests. Available from American Association of State Highway and Transportation
Current edition approved Oct. 1, 2022. Published October 2022. DOI: 10.1520/ Officials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,
D8360-22. http://www.transportation.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D8360 − 22
3.2 Definitions of Terms Specific to This Standard: 6. Apparatus
3.2.1 RT ,n—rutting tolerance index, the value used to
Index 6.1 Test Apparatus—An IRT test apparatus consists of an
evaluate mixture resistance to rutting.
axial loading device, a load cell, one upper loading strip and
lower supporting cradle, specimen deformation measurement
3.2.2 P ,n—peak load (kN). See 10.3.
max
devices, and a data acquisition system. Alternatively, the load
3.2.3 τ,n—shear strength (MPa).
f
cell, top loading strip and lower supporting cradle, specimen
deformation measurement devices, data acquisition system, or
4. Summary of Test Method
combinations thereof can be integrated into a test fixture.
4.1 The ideal rutting testing is conducted through the
6.1.1 Axial Loading Device—Theloadingapparatusshallbe
application of a monotonic compressive load along a vertical capableofdeliveringloadingincompressionwithacapacityof
diametral plane of a cylindrical specimen of asphalt concrete at least 15 kN. It shall be capable of maintaining an average
centered in the testing apparatus. The load is applied such that
constantdeformationrateof50 62.0mm/min.Ahydraulic,an
an average constant load-line displacement (LLD) rate of 50.0 electromechanical,screw-driven,orapneumaticloadingframe
6 2.0 mm/min is obtained and maintained for the duration of
may be used if it can maintain a displacement rate required to
the test. Both the load and LLD are measured during the entire induce the average constant deformation rate of 50 6 2.0
duration of the test and are used to calculate the RT .
mm/min.
Index
6.1.2 Load Cell—The load cell shall have a readability of
4.2 This test procedure considers both elastic/viscoelastic
10N and a capacity of at least 15 kN.
properties of the asphalt mix and its strain-hardening charac-
6.1.3 Upper Loading Strip and Lower Supporting Cradle—
teristics and is developed based on shear strength principle.
Steel loading and supporting cradle with a concave surface
having a radius of curvature equal to the nominal radius of the
5. Significance and Use
test specimen. For specimens with a nominal diameter of 150
5.1 The ideal rutting test (IRT) is used to determine asphalt
62mm,theupperloadingstripshallbe19.05 60.3mmwide
mixture rutting resistance at high temperature in the range of
and the lower supporting cradle shall be as depicted in Fig. 1.
50 6 15°C, depending on local climate. The specimens are
The length of the loading strips shall exceed the thickness of
readily obtained from Superpave Gyratory Compactor (SGC)
the specimen by at least 5 mm. The outer edges of the bottom
compacted cylinders with a diameter of 150 6 2 mm, with no
supporting cradle shall incorporate a fillet (Fig. 1) to remove
cutting, gluing, drilling, or instrumentation required. Similarly,
sharp edges.
field cores with a diameter of 150 6 2 mm can be tested to
6.1.3.1 Option A—The loading strip and cradle can be part
measure rutting resistance of in-place asphalt mixtures.
of a test fixture, similar to that shown in Fig. 1, in which the
lower supporting cradle is mounted on a base having two
NOTE1—Fieldcoresmayneedcuttingtoarightthicknessrangingfrom
perpendicularguiderodsorpostsextendingupward.Theupper
38 mm to 95 mm. This test standard is not applicable to the specimens
with a diameter other than 150 6 2 mm, regardless of laboratory- loading strip shall be clean and freely sliding on the posts.
compacted specimens or field cores.
Guide sleeves in the upper segment of the test fixture shall
direct the specimen contact strip without appreciable binding
5.2 The RT of an asphalt mixture is calculated from the
Index
or loose motion in the guide rods.
peak load (or shear strength). The RT is a performance
Index
6.1.3.2 Option B—The loading strip and cradle can be part
indicator of the rutting resistance of asphalt mixtures contain-
of a test fixture, similar to that shown in Fig. 2, in which the
ing various asphalt binders, asphalt binder modifiers and
lower supporting cradle is mounted on the lower loading strip
additives, aggregate blends, fibers, and recycled materials.
of an indirect tensile fixture with two perpendicular guide rods
Generally, the higher the RT value, the better the rutting
Index
or posts extending upward. The upper loading strip shall be
resistance and consequently the smaller the rut depth in the
cleanandfreelyslidingontheposts.Guidesleevesintheupper
field. Users can employ the RT and associated criteria to
Index
segment of the test fixture shall direct the specimen contact
identify rutting-prone mixtures during mix design and produc-
strip without appreciable binding or loose motion in the guide
tion quality control/assurance.
rods.
NOTE 2—The quality of the results produced by this standard are
6.1.4 Internal Displacement Measuring Device—The dis-
dependent on the competence of the personnel performing the procedure
placement measurement acquisition system shall have a read-
and the capability, calibration, and maintenance of the equipment used.
ability of 0.01 mm and a range sufficiently large to handle the
Agencies that meet the criteria of Specification D3666 are generally
considered capable of competent and objective testing, sampling, expected total displacement during the test. The machine
inspection, etc. Users of this standard are cautioned that compliance with
stroke linear variable differential transformer (LVDT) or other
Specification D3666 alone does not completely ensure reliable r
...