What is the impact of adding recycled asphalt pavement (RAP) to a mix?

Adding recycled asphalt pavement (RAP) to an asphalt mix significantly improves both sustainability and cost-effectiveness. The use of RAP allows for the reuse of materials that would otherwise be discarded, leading to less waste and a reduction in the demand for new raw materials. This not only makes the asphalt mix more environmentally friendly but also helps to lower production and material costs, making it economically advantageous for construction projects.

Utilizing RAP contributes to the overall durability and performance of the asphalt surface as well, as the older asphalt can provide beneficial properties when blended with new materials. This practice supports the principles of recycling in construction and aligns with efforts to minimize the environmental impact of road-building processes.

In contrast, the other options do not accurately reflect the benefits of adding RAP. The viscosity of the asphalt mixture does not consistently decrease with RAP addition; it can be influenced by the specific grades of asphalt used and the proportion of RAP in the mix. While some scenarios may lead to variations in density, the overall impact of RAP is more about performance and sustainability rather than merely reducing density or having no effect at all.