Assessment of Hot Mix Asphalt Performance Using Reclaimed Asphalt Pavement as a Sustainable Partial Replacement

Although Ethiopia’s road network has expanded significantly in recent years, maintaining long-term pavement performance remains a major challenge. In response to increasing sustainability concerns, modern road construction practices emphasize the recycling and reuse of existing asphalt materials, an approach that has been successfully applied since the early 1900s and offers both technical and environmental benefits. This study investigates the laboratory performance of hot mix asphalt (HMA) incorporating varying proportions of reclaimed asphalt pavement (RAP) for binder course applications. Comprehensive material characterization tests were conducted on all constituent materials to evaluate their suitability for asphalt mixture production. Marshall mix design and testing were subsequently performed on both conventional (control) and RAP-modified mixtures to assess key mechanical properties. To further evaluate field performance, moisture susceptibility, indirect tensile strength (ITS), and Hamburg wheel tracking tests were carried out on the prepared mixtures. The results indicate that all RAP-containing mixtures satisfied the Marshall design criteria and performance specifications. Furthermore, the mixtures demonstrated acceptable resistance to moisture damage, adequate tensile strength, and satisfactory rutting performance under laboratory conditions. These findings confirm that binder course asphalt mixtures incorporating RAP can be successfully produced while meeting the required engineering and performance standards. The study concludes that incorporating up to 40% RAP in HMA mixtures is technically feasible for binder course applications. Such mixtures can satisfy both Marshall and performance-based requirements while providing economic advantages through reduced material consumption and lower production costs compared with conventional asphalt mixtures. The findings support the broader adoption of RAP as a sustainable and cost-effective solution for pavement construction and rehabilitation. Keywords: : reclaimed asphalt pavement; Marshall properties; performance test; indirect tensile strength; Hamburg wheel tracking