Fatigue Performance of Asphalt Mixtures Prepared with RAP and Recycling Agents: A Study at the Fine Aggregate Matrix Scale

A fine aggregate matrix (FAM) has been used as a tool to evaluate the effects of reclaimed asphalt pavements (RAP) on the fatigue performance of asphalt mixtures. This study evaluated the fatigue performance of FAMs produced with RAP by comparing their strain tolerance at the same number of loading cycles. Three failure criteria were adopted to calculate the mixture strain tolerance: GR, Cf, and DR. The FAMs were prepared with RAP at 0%, 20%, and 40%, a PG 64-22 binder, a bio-oil, and a petroleum-based aromatic oil. The addition of RAP increased the stiffness and reduced the relaxation rate of the mixtures, resulting in FAMs that are stiffer and more susceptible to damage. The findings showed consistent conclusions among the three fatigue failure criteria. The addition of the petroleum-based oil proved to be promising by increasing the strain tolerance of the mixtures containing 20% RAP, while adding the bio-oil was the best option to increase the strain tolerance of the mixtures containing higher RAP proportions (40%).