Effects of High Reclaimed Asphalt-Pavement Content on the Binder Grade, Fatigue Performance, Fractionation Process, and Mix Design

The primary objective of this research is to examine the effects of reclaimed asphalt pavement (RAP) amounts and fractionation methods on the mix design of high-RAP content surface mixes. To determine the distribution of fine aggregates and binder in RAP stockpile, the sieve-by-sieve analysis of RAP materials was performed. A single virgin asphalt binder performance grade modification was effective in mitigating the negative effect of the aged RAP binder. On the basis of the beam fatigue test, there was no significant change in predicted fatigue life of asphalt mixtures with high-RAP contents. Nine mix designs were performed for mixtures with three different amounts of RAP contents and three different fractionation methods. When the RAP materials were fractionated, the film thickness increased and the dust-binder ratio decreased. Only the fractionated RAP mix with 30% RAP materials met all mix design criteria, including the Iowa Department of Transportation’s film thickness requirement.