Effect of rap aging and its proporations on the performance of asphalt mixtures

Highway agencies are increasingly using Reclaimed Asphalt Pavement (RAP) material for road construction and rehabilitation. RAP offers economic benefits by reducing the need for neat bitumen in freshly blended asphalt mixtures. While previous studies have emphasized RAP’s importance in conventional asphalt mixtures, our research focuses on the impact of RAP at various proportions and ages. Specifically, we explore the “aging” effect of RAP, where lighter oils and maltenes in the binder evaporate as asphalt oxidizes, leading to pavement deterioration. We formulated RAP mixtures at different percentages and ages, comparing their characteristics to a conventional mixture. Our study examines two grades of asphalt mixtures, adhering to Egyptian standards, with RAP content ranging from 0 to 30% and sourced from materials aged 9–15 years. High RAP content affects fatigue performance, stiffness, and permanent rut deformation in hot mix asphalt. Laboratory tests, including dynamic modulus (DM) and traditional Marshall volumetric tests, assess long-term deformation capabilities.