Abstract: Porous mixtures are used in the wearing course for their ability to drain water, reduce run-off, minimise aquaplaning and reduce traffic noise. However, their limited durability remains a key challenge. This study investigates the use of polyurethane as a binder and recycled rubber as a partial replacement for mineral aggregate to improve the elasticity and durability of these mixtures. Mechanical and functional tests were used to evaluate and compare experimental mixtures containing up to 20% rubber with conventional asphalt mixtures. The results showed that polyurethane increased indirect tensile strength and provided superior resistance to surface abrasion compared to conventional asphalt. Nevertheless, the results showed that polyurethane increased Cantabro loss and the incorporation of rubber significantly worsens the strength properties and increases particle loss. An environmental assessment using a cradle-to-gate Life Cycle Assessment (LCA) revealed that although this mixture supports waste valorisation, polyurethane production and long-distance transport dominate the global warming potential, making polyurethane mixtures markedly higher in CO2 equivalent to the reference. Future studies should measure in-service durability and apply cradle-to-cradle LCA.

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