Sensitivity of Untreated Reclaimed Asphalt Pavement to Moisture, Density, and Freeze Thaw

Abstract

The objective of the research was to assess the structural capacity of reclaimed asphalt pavement (RAP) as a base layer and to investigate the effect of RAP content, moisture content (MC), freeze-thaw (F-T) conditioning, and dry density (DD) on the resilient modulus of untreated RAP as a base layer. The resilient modulus test was conducted in the laboratory for specimens containing different ratios of RAP and aggregate. All samples containing RAP had higher resilient modulus and lower permanent deformation compared to virgin aggregate. Resilient modulus of RAP decreased as the MC increased. At low MCs there was no clear effect of MC on permanent deformation. However, as moisture increased to the wet side of the optimum MC curve, loss of stability was clear. F-T conditioning did not have a negative impact on the stiffness of RAP; this was explained by the low ability of RAP/aggregate blends to hold moisture. DD effect on the resilient modulus was dependent on the level of MC, but developed models showed that increasing DD would increase