Enhancing RAP-Based Pavement Layers with Industrial Byproduct Blends for Improved Performance and Sustainability

The recycling of asphalt pavement has become a widely accepted practice in the transportation industry, driven by environmental, economic, and social benefits. Reclaimed Asphalt Pavement (RAP) consists of materials obtained from existing asphalt pavements that are no longer viable for reconstruction or resurfacing. Before RAP can be reused in construction, especially in base and subbase layers, it must undergo laboratory testing to verify its suitability. While many transportation agencies have embraced the use of RAP in unbound layers, its application is often restricted due to its relatively low strength, necessitating the use of stabilizing additives. To overcome this limitation, recent research efforts have focused on enhancing the performance of RAP by blending it with industrial byproducts. This study investigates the effectiveness of combining RAP with cement, fly ash, and ground granulated blast furnace slag (GGBS) to produce sustainable, high-performance pavement materials. Laboratory tests were carried out to assess the physical characteristics and mechanical performance of various mix combinations. A key focus of this study was to evaluate a mixture containing 50% RAP and 50% virgin aggregate (VA), stabilized with 7% cement. This specific blend demonstrated a compressive strength of 4.5 MPa, indicating its suitability for pavement applications. Among the various combinations tested, the 50:50 RAP:VA mixture with cement showed superior performance. It not only met the required strength criteria but also offered significant cost and environmental benefits by reducing the need for natural aggregates and lowering overall construction expenses. Incorporating RAP with stabilizing agents such as cement, fly ash, and GGBS significantly enhances the strength and durability of the final product, making it a viable and sustainable option for modern pavement construction. As the transportation sector increasingly emphasizes sustainability, integrating recycled materials like RAP into infrastructure projects will be critical in achieving long-term environmental goals and building resilient road systems.