Comparative sustainability analysis of RAP and recycled sand from solid urban waste into porous asphalt mixtures

Porous asphalt (PA) pavements contribute to improved road safety and acoustic comfort; however, their service life is often limited due to binder aging, particle loss, and clogging phenomena which lead to frequent maintenance interventions and increased material consumption. In line with European strategies, the incorporation of secondary raw materials represents a promising strategy to reduce natural resource depletion and support circular economy principles in road infrastructure. Despite these advantages, the use of recycled materials is still limited due to concerns related to mechanical performance and durability. The study aims to evaluate the influence of reclaimed asphalt pavement (RAP) and sand derived from municipal solid waste (MSWS) on the mechanical response and sustainability of porous asphalt mixtures. Three mixtures were designed: a reference mixture composed solely of virgin materials, a mixture containing 10% MSWS, and a mixture including 30% RAP. From a mechanical performance perspective, the mixture containing RAP exhibited a moisture damage increase of more than 4% compared to the traditional solution, while the mixture incorporating MSWS showed a significant reduction in rutting susceptibility of 66%. From an environmental perspective, the LCA results revealed that the MSWS mixture was particularly effective in reducing water consumption and the overall life cycle environmental impact, whereas the RAP mixture provided notable benefits during the production phase and in terms of fossil resource conservation. Based on the combined mechanical and environmental analyses, the study demonstrates that PA mixtures incorporating secondary raw materials can represent a technically feasible and environmentally sustainable alternative to conventional solutions.