Advancing Circular Economy in Asphalt Pavements by Enhancing Reuse of Reclaimed Asphalt and Extending Pavement Service Life

Abstract

The European Union's ambitious Green Deal relies on the application of principles such as thecircular economy in high-carbon-emitting sectors to achieve climate neutrality by 2050. In asphaltpavement construction, enhancing the durability of asphalt pavements and reusing reclaimedasphalt pavement (RAP) are among the most effective circular economy strategies to significantlycontribute to the neutrality goal. These strategies lead to emission reduction by decreasing the needfor raw material resources, minimising waste generation, and lowering energy consumption inasphalt pavement construction.The first part of this thesis focuses on improving the durability of asphalt pavements by identifyingthe key ageing mechanisms that contribute to the hardening and premature deterioration of asphaltpavements. This part also examines the practical effectiveness of additives described in theliterature as promising anti-ageing additives to reduce ageing and consequently increase the servicelife of asphalt pavements.The second part evaluates the feasibility of using one of the additives considered in the first part torestore the physical, rheological, and chemical properties of aged RAP binders. The results indicatethat the additive can partially restore the properties of RAP binders to those of neat asphalt binders,improving the performance and durability of asphalt mixtures with high RAP content.Moreover, this research underscores the potential of circular economy principles, particularlyregarding the enhancement of asphalt pavement durability and the reuse of RAP in asphaltpavement construction, to make substantial progress toward the overarching goal of EU climateneutrality.