Mechanical properties of reclaimed asphalt pavement — natural aggregate blends for granular base

An experimental study investigated the California bearing ratio (CBR), shear strength, stiffness, and cyclic creep properties of crushed, reclaimed asphalt concrete pavement (RAP) — natural aggregate blends for granular base and subbase. The CBR was found to depend on the properties of the constituent materials and the compactive effort used to prepare the specimens. It was concluded that the CBR test may not be appropriate for evaluating the suitability of blended material for granular base construction. Based on the triaxial tests, it was observed that the addition of RAP to natural aggregate (Ontario Granular A) reduces the shear strength slightly and tends to increase the accumulated strain (deformation) that develops due to repetitive loading. The influence of RAP on the mechanical properties, including ‘elastic’ modulus, was sensitive to specimen preparation and preconditioning. For certain combinations of RAP and Granular A, the mechanical properties were similar to those of Granular A. The key to a stable blend was found to be compactive effort.