Laboratory Evaluation of Mixes Containing Recycled Asphalt Pavement (RAP)

ABSTRACT This paper presents the findings of a laboratory-based research project that evaluated the impact of three RAP sources at three levels of RAP content (0, 15, and 30%) on the mechanical properties of the final mix. Two asphalt binder grades were targeted for the final mix. The binder grade for the new asphalt binder was selected using appropriate blending charts for high and low temperatures. Overall the addition of RAP to a mixture resulted in an acceptable moisture resistance, however a reduction in the unconditioned and conditioned tensile strength was observed. In most of the cases, the addition of RAP to a mixture resulted in an equivalent or better rutting resistance than the virgin mix (0% RAP). Depending on the RAP source and content, the addition of RAP to a mixture with an unmodified target asphalt binder resulted in either a better or worse fatigue resistance. On the other hand the addition of RAP to a mixture with a polymer modified target asphalt binder resulted in a worse fatigue resistance regardless of the RAP source and content. Finally, the addition of RAP to a mix resulted in a similar or better resistance to thermal cracking than the virgin mix and reasons for that were proposed.