15 - The use of recycled plastic as partial replacement of bitumen in asphalt concrete

Abstract

Roads are important assets to enable people and freight transport between different locations; nevertheless, their construction is mainly based on asphalt mixtures, which emit a great amount of carbon to the atmosphere because of their bitumen content. In the end, this is translated into harmful environmental impacts. In order to decrease them, this research aimed at substituting part of this bitumen by polystyrene (PS) wastes in both asphalt concrete (AC-16) and porous asphalt (PA-16) mixtures. Three different types of PS wastes were used: general purpose polystyrene (GPPS), also known as crystal polystyrene, high impact Polystyrene (HIPS), and polystyrene from hangers (HPS). In addition, reference mixtures for both AC-16 and PA-1 were designed and dosed for their comparison with the experimental mixtures, where the amount of bitumen was reduced and substituted by polymers. After a full laboratory characterization of all the experimental mixtures, a life cycle assessment (LCA) was carried out to evaluate their environmental performance in comparison with reference mixtures. The results obtained suggested that the substitution of bitumen by PS might limit the environmental impact of asphalt mixtures when considering the lifetime extension achieved by the reduced plastic deformation provided by the presence of PS.