Rapid urbanization and the continuous growth of transportation infrastructure have increased the demand for road construction materials worldwide. Conventional pavement construction depends heavily on virgin aggregates and bitumen, resulting in excessive resource consumption, environmental degradation, high energy usage, and increased greenhouse gas emissions. In recent years, Recycled Asphalt Pavement (RAP) has gained significant attention as a sustainable and cost-effective solution in highway engineering. RAP is produced by reclaiming and processing old asphalt pavements for reuse in new pavement construction. The reuse of RAP helps reduce construction waste, conserve natural resources, and minimize the environmental impact associated with road development. This study examines the importance of RAP in sustainable road construction by analysing its composition, production methods, engineering properties, environmental benefits, and recent technological developments. It also discusses different recycling techniques such as hot and cold recycling, along with the challenges related to aged binder stiffness, moisture susceptibility, and quality control. Recent advancements including rejuvenators, warm mix asphalt technology, and AI-based pavement analysis have further improved RAP performance and durability. The study concludes that RAP is an effective sustainable pavement material that can reduce construction costs and carbon emissions while maintaining satisfactory structural and functional pavement performance when proper mix design and quality control practices are adopted.

Keywords— Recycled Asphalt Pavement (RAP),Sustainable Road Construction, Asphalt Recycling, Flexible Pavement. Sustainable Pavement Materials. Green Highway Technology