Towards more sustainable infrastructures through circular processes: Environmental performance assessment of a case study pavement with recycled asphalt in a life cycle perspective

Promotion of technological and ecological transition through innovations on paving materials and their production leads to more sustainable roads. Highly recycled Hot Mix Asphalt (HMA) mixtures containing Reclaimed Asphalt Pavement (RAP) were considered to produce eco-friendly materials for highways’ base and binder layers. The asphalt plant type is a key factor to increase RAP recycling rate in HMA mixes. A traditional (30% RAP) and a novel (70% RAP) batch plants were considered, with different initial investments and maintenance costs. The environmental and economic impacts of HMAs production in the chosen plants were compared, as a decisionmaking tool for innovation and plant investments in asphalt industry. The investigated scenarios were: 1 ton of HMA and 1 km of one-way highway considering construction/maintenance processes over 20-year; which modelled RAP as either an internal or an end-of-waste source of a company. The results highlighted positive effects of using higher RAP content in a novel asphalt plant reducing the CO2,eq emissions during the production cycle from -28% up to -39% approx. depending on the model, and during the entire service life of the pavement (negligible and - 13% approx.). From economic viewpoint, increasing the RAP quantity a decreasing of HMA total cost was experienced, but additional related cost on transport and RAP recycling should be considered for a comprehensive evaluation of the proposed solution.