Assessing permanent deformation potential of asphalt mixtures based on viscoelastic characteristics

In this study, permanent deformation potential of different asphalt mixtures subjected to the same aging condition was assessed, based on viscoelastic characteristics from the dynamic modulus (DM) test. First it was shown that the HWTT and RLPD test results were not well correlated, which might be due to the differences in the boundary condition and the impacts of moisture damage and stripping in the HWTT. The analysis results suggested that the shape parameter (gamma) of the DM master-curves could be utilized to assess the rutting resistance potential of the asphalt mixtures from the RLPD test, compared to other rheological parameters such as the inflection point frequency and beta. The |E*| at the RLPD test condition was well correlated to the rutting performance compared to the asphalt mixture's rutting parameter |E*|/sind and the |E*| at the inflection point frequency. A novel rutting parameter (VERIndex) was developed to assess the rutting resistance potential of the asphalt mixtures, which simultaneously accounts for the |E*| and slope of the DM master-curves. Thereafter, the cracking and rutting performance thresholds were proposed, and, correspondingly used in the performance space diagram to aid with implementing the balanced mix design approach using the viscoelastic characteristics of asphalt mixtures.