Characterization of the structural behavior of reclaimed asphalt pavement as pavement base layer

About 100 million tons of reclaimed asphalt pavement (RAP) are produced each year during pavement rehabilitation activities which presents a major solid waste concern. The main objective of this research is to develop an understanding of the structural behavior of untreated RAP and RAP/aggregate blends. The research investigates the effect of state of stress, moisture content, dry density and freeze-thaw conditioning on the resilient modulus (MR) and shear strength of untreated RAP and RAP/aggregate blends as a base layer. The research investigates the effect of variability in determining the base layer resilient modulus for RAP compared to granular material and the impact of RAP resilient modulus variability on predicted pavement performance. The research also investigates the permanent deformation characteristics of RAP under repeated loading and the main factors affecting RAP permanent deformation.;Through the work conducted in this research, it was found that all samples containing RAP had a higher resilient modulus compared to virgin aggregate. The MR of RAP/aggregate blends were less sensitive to bulk stress and more sensitive to confining pressure and deviator stress compared to base aggregate. MR of RAP was sensitive to the rate of loading. The effect of moisture content on RAP/aggregate blends was typical of unbound granular material, as moisture content increased the MR was decreased and the permanent deformation was increased. Freeze-thaw conditioning did not have a negative impact on the stiffness of RAP. Dry density effect on the resilient modulus was dependent on the level of moisture content.