Laboratory Evaluation on Resilient Modulus and Rate Dependencies of RAP Used as Unbound Base Material

Abstract

Laboratory tests were conducted to evaluate the resilient modulus and rate dependencies of unbound reclaimed asphalt pavement (RAP), crushed limestone, and crushed gravel prepared with the same gradation and equivalent compaction work. Resilient modulus, permanent deformation, and strain energy loss were studied through repeated triaxial and creep testing at different temperatures. The results from this study indicated that RAP tended to have higher resilient modulus when tested as unbound aggregates. However, the permanent deformation of RAP tended to be higher than the crushed stones at ambient temperature. Due to viscoelasticity, the strain (load) rate and temperature dependency of unbound RAP base material was significantly higher than those of crushed limestone and gravel. The temperature dependency of unbound RAP base could significantly affect the performance of asphalt pavements.