Comparative Study of Mechanistic-empirical Structural Design Methods Applied to Sustainable Asphalt Mixtures

Nowadays, there is a growing interest in achieving sustainable alternatives to conventional flexible pavements. The incorporation of recycled materials into asphalt mixtures has become a departure point. This study focuses on developing sustainable asphalt mixtures incorporating different residues to find a material that performs well on both technical and environmental grounds. Mixtures with recycled materials and others are compared on a pavement structure. A mechanistic-empirical pavement design method is used to carry out analyses in different conditions. A Life Cycle Assessment is conducted to consider the balance of positive and negative environmental aspects of each mixture and pavement structure. The results indicate that all mixtures with sustainable features have a longer life span and an enhanced performance. They also incur higher impacts per tonne produced. However, the “avoided impact” is considered in their favour. Mixtures with enhanced mechanical properties are key to achieving long-term environmental benefits. The usage of local materials is also essential. Proving that unconventional mixtures have a satisfactory performance requires innovative, properly calibrated models and a thorough material characterization. Accurately reflecting on their in-service behaviour is key to evaluating the environmental benefits.