comparison of alternative asphalt concrete rut characterization

BERTHELOT, CROCKFORD & LYTTON 8unconfined compressive strength test was found not to provide proper ranking of the Radisson SPS-9Aasphalt concrete mixes concomitant to field rutting performance after three years of service.4.4 SHRP Shear Tester CharacterizationThe Strategic Highway Research Program developed a prototype suite of tests to characterize thethermomechanical behavior of asphalt concrete mixes and they are specified in AASHTO TP7-94 (25).The SHRP suite of shear tests include: volumetric-hydrostatic test, uniaxial strain at constant radius test,simple shear at constant height test, frequency sweep shear at constant height test, and repeated shear atconstant stress ratio test.The repeated shear at constant height is specified in AASHTO TP7-94 (25) as optional procedure F.However, it was not performed in this study. Asphalt concrete samples used for the SHRP Level III sheartester characterization were prepared using SHRP specified gyratory compaction protocols as outlined inAASHTO TP4 (25). Figure 2 shows an asphalt concrete sample mounted in the SHRP shear tester for thevolumetric-hydrostatic and uniaxial strain at constant radius tests. Figure 3 shows an asphalt concretesample mounted in the SHRP shear tester for the simple shear at constant height, frequency sweep shearat constant height and repeated shear at constant stress ratio tests.Figure 2 SHRP Shear Tester Uniaxial Strain and Volumetric-Hydrostatic Sample Configuration