ASTM D8259/D8259M-21

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: D8259/D8259M − 21
Standard Test Method for
Rotary Wheel Testing (RWT) of Compacted Asphalt
1
Mixtures
This standard is issued under the fixed designation D8259/D8259M; 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.
temperature of 60 °C [140 °F] because “(1) it approximates the observed
1. Scope
high average temperature of most pavements, (2) it is close to the high
1.1 This test method describes a procedure for testing the
temperature performance grade classification of the asphalt binder used in
rutting and moisture susceptibility of asphalt specimens using most local applications, (3) it allows a test to be performed in an
acceleratedtimeframe(about2 hexcludingpreconditioningtime),and(4)
the RotaryWheelTester (RWT). Superpave Gyratory Compac-
research on rut testing has shown [that] the asphalt binder seems to have
tor (SGC) specimens (Test Method D6925) are wrapped,
the most control over the test results at lower test temperatures.” The
conditioned, submerged in water, and confined between three
ruggedness study was completed at 60 °C [140 °F] using PG 64-10 with
metal wheels in continuous synchronized rotation with each
50 % RAC asphalt mixture. The precision study was completed at 60 °C
wheel applying a fixed load around the periphery of the [140 °F] using PG 64-10 with 50 % RAC asphalt mixture for two of the
mixtures evaluated and using PG 76-22 for the third mixture considered.
specimen. The system records the number of load cycles
One may wish to consider lower test temperatures because Lemke and
applied to the specimen, the deformation of the specimen (rut
Bahia (2019) reported reducing the test temperature from 60 °C [140 °F]
depth), the loading rate, the temperature of the water, and
to 52 °C [125.6 °F] when testing PG 58S-28 and PG 58H-28 asphalt
Sigma, which is an indication of specimen roundness.
becauseofprematurefailure.Note8includesasuggestionforselectingan
alternative test temperature based on the binder if one chooses to do so.
1.2 The test method is used to determine the premature
NOTE 4—The University of Wisconsin at Madison Modified Asphalt
rutting susceptibility of asphalt mixtures by measuring rut
Research Center (2017) reported that the City of LA selected 6900 load
depth as a function of number of load cycles throughout the
cycles as the maximum load cycles because “initial observations from
tests showed that most samples tested showed their performance well
test.
beforethesevalues(6900loadcyclesand6.0mm[0.24in.])wereattained
1.3 This test method also measures the potential for mois-
... while those that exhibited low rut depth in the field and no moisture
ture damage effects because the specimens are submerged in
susceptibilityshowedtestresultcurvesthatbehavedasasymptotestotheir
initial creep slope until the maximum number of cycles (30 000 cycles) of
temperature-controlled water during preconditioning and for
the machine was attained.” 6900 load cycles was used in both the
the duration of the test.
ruggedness and precision work as well. The machine has an allowable
1.4 The parameters of the test are shown in Table 1. See an
range of 300 to 30 000 load cycles.
NOTE 5—The University of Wisconsin at Madison Modified Asphalt
example of the test parameters used in Appendix X1.
Research Center (2017) reported that the City of LA selected 6.0 mm
NOTE 1—This test uses a typical specimen produced by a Superpave
[0.24 in.] as the maximum rut depth because “initial observations from
gyratory compactor.
tests showed that most samples tested showed their performance well
NOTE 2—The ruggedness study identified air void content as the most
beforethesevalues(6900loadcyclesand6.0mm[0.24in.])wereattained
influential factor evaluated and recommended a tolerance of 60.25 % to
... while those that exhibited low rut depth in the field and no moisture
minimize the effect of air void content on the test results. The precision
susceptibilityshowedtestresultcurvesthatbehavedasasymptotestotheir
study evaluated three asphalt mixtures with specimen air void contents
initial creep slope until the maximum number of cycles (30 000 cycles) of
ranging from 2.87 % to 3.23 %, from 4.28 % to 4.64 %, and from 5.77 %
the machine was attained.” 6.0 mm [0.24 in.] was used in both the
to 6.19 %. Precision statements covering the air void content ranges of
ruggedness and precision work as well.
2.75 % to 4.75 % and 5.75 % to 6.25 % can be found in Sectio
...