Valorization of Reclaimed Asphalt Pavement (RAP) from the Highway Materials Circularity

Abstract The increasing demand for natural resources in highway construction presents significant environmental and economic challenges. A key issue is the disposal of reclaimed asphalt pavement (RAP), which is often discarded in landfills, despite its potential for reuse in new asphalt mixtures. Although several studies have investigated RAP incorporation, the influence of its particle size distribution on mechanical performance remains an underexplored area, creating a gap in understanding the material’s optimal reuse conditions. This study aims to evaluate the valorization of RAP in asphalt mixtures by characterizing its properties and analyzing the effects of partial aggregate replacement (0%, 25%, 50%, and 100%) on mechanical performance, considering both fine and coarse fractions. The methodology involved granulometric analysis, chemical and thermal characterization, and mechanical tests such as Marshall stability, flow, indirect tensile strength, and abrasion resistance. The results showed that increasing RAP content reduced the need for new bituminous binder, with a 50% RAP mixture requiring only 2.80% of new binder compared to 4.30% in the control sample. Marshall stability improved with RAP incorporation, reaching a maximum of 13312.63 N for a 50% RAP mixture with basaltic fines, while a 100% RAP mixture exhibited 11311.87 N stability. Indirect tensile strength also increased with RAP incorporation, peaking at 0.98MPafor the 50% RAP mixture with basalt fines. However, excessive RAP content led to higher deformation susceptibility, as evidenced by a 524 c.mm flow in the 100% RAP mixture. The findings indicate that RAP can be effectively incorporated into new asphalt layers, optimizing resource use and reducing environmental impact. The best balance between performance and sustainability was achieved at 50% RAP content, particularly when combined with basaltic fines. These insights contribute to advancing circular economy principles in road engineering, promoting more sustainable pavement solutions.