Rheological and mechanical properties of blended asphalts containing recycled asphalt pavement binders

The relationship between rheological and mechanical properties and recycled asphalt pavement (RAP) binder percentage in blended asphalt was studied to examine the permanent deformation, fatigue, and low temperature cracking resistance characteristics. Two base asphalt binders (AC-10 or PG 58-28 and AC-20 or PG 64-22) were blended with various amounts of RAP binders taken from two hot-mix asphalt plants in Rhode Island, i.e., 0, 10, 20, 30, 40, 50, 75, and 100 wt % of blended asphalt binder. A good linear relationship between log-log rheological properties and the amount of RAP binders was obtained . Addition of RAP binder increased the resistance against permanent deformation. A rise in RAP binder content increased the fatigue cracking parameter (G*sinδ). Thus, the Superpave criteria of G*sinδ may control the maximum amount of RAP addition not to have fatigue cracking. The results of the Bending Beam Rheometer test, conducted to examine the resistance properties of blended asphalt binder against thermal cracking at low temperatures (-6°, -12°, -18°, and -24°C), showed that the creep stiffness increased and the m-value decreased for all temperatures as the RAP content increased. In quasi-static loading experiments, the compressive strength and the stiffness increased and the ductility decreased as the RAP binder amount increased. Other properties studied were fracture toughness and dynamic response of blended asphalt binder