Rutting and Fatigue Performance of Aged Modified Asphalt Binders

Rutting and fatigue are two major pavement distresses which affect both structural and functional performances of the flexible pavement. Linear amplitude sweep (LAS) and Multiple stress creep and recovery (MSCR) are two advanced methods to examine fatigue and rutting performance of asphalt binders respectively. The present study aims at examining the effect of ageing (short term and long term) and modification (polymer and warm mix) on the performance of asphalt binders. Both LAS and MSCR tests were conducted at different temperatures, stress/strain levels, and ageing conditions. Stress is a parameter that influences the performance of asphalt binder significantly so stress susceptibility was also evaluated for all the binders at different temperatures and ageing conditions. From the test results, it was found that ageing improves the stress susceptibility of the asphalt binders with respect to rutting parameters on the other hand ageing deteriorated the stress susceptibility concerning fatigue parameters. The applicability of different asphalt binders at different temperature and traffic conditions was also examined and it was found that most of the binders failed to fulfill the criteria at the temperatures which were well below their high-temperature performance grades. This highlighted the need to revise the Superpave criteria.