Evaluation of recycled asphalt mixtures with different RAP contents and the effect of recycling agent

Abstract

This research evaluated recycled asphalt mixtures (RAMs) for application as wearing course in heavy traffic highways. The main objectives were to investigate the effect of different RAP contents and the effect of a recycling agent (RA) on the mechanical properties of RAMs. Recycled asphalt mixtures with low (10, 20 and 25%) and high (35, 50 and 65%) RAP contents were evaluated. Two of these mixtures (25 and 50% RAP content) were also evaluated after the addition of the RA. The results indicate that conditioning the RAP during the production of RAMs influences the RAP binder activation and the mechanical behaviour of the mixtures. RAMs with high RAP contents presented better resistance to permanent deformation and resulted in satisfactory resistance to fatigue cracking due to the activation of the RAP asphalt binder. Finally, the addition of the RA improved fatigue resistance for higher amounts of RAP without reducing rutting resistance.