How does recycled asphalt pavement benefit sustainability in road infrastructure?

Recycled asphalt pavement (RAP) benefits sustainability in road infrastructure through several key mechanisms. First, it reduces the demand for virgin materials, such as aggregates and asphalt binder. Producing these virgin materials requires significant energy and resources, and their extraction and transportation contribute to greenhouse gas emissions. By using RAP, the need for these virgin materials is reduced, conserving natural resources and lowering the carbon footprint of road construction. Second, RAP reduces the amount of waste sent to landfills. Instead of disposing of old asphalt pavement, it is reused in new pavement construction, diverting waste from landfills and reducing landfill space requirements. Third, RAP can reduce energy consumption associated with transportation. Because RAP is often processed on-site or at nearby facilities, the distance that materials need to be transported is reduced, lowering fuel consumption and emissions. Fourth, RAP can sometimes improve the performance of asphalt mixtures. The aged asphalt binder in RAP can provide increased stiffness and resistance to rutting, leading to longer-lasting pavements. In summary, RAP promotes sustainability by conserving resources, reducing waste, lowering energy consumption, and potentially improving pavement performance.