Design of Sustainable Asphalt Mixtures for Bike Lanes Using RAP and Ceramic Waste as Substitutes for Natural Aggregates

Abstract

The European Union is promoting a circular economy in which waste management plays an essential role. Although many studies focusing on the use of recycled materials in the manufacture of asphalt mixtures for roads have been developed, studies related to the use of recycled materials for the construction of bike lanes are scarce. In this context, the main objective of this research is to explore the behaviour of asphalt mixtures with high replacement rates of recycled materials—reclaimed asphalt pavement (RAP) and ceramic waste—by natural aggregates for the construction of bike lanes. A total of six types of asphalt mixtures were designed by combining the content of the recycled materials and natural aggregates, with replacement rates ranging from 50% to 100%. The asphalt mixtures were characterized by determining the bulk and maximum density; the void content in the mixture; and the aggregate, stability, and deformation. In conclusion, the mixture C50R50, which consists of a full replacement of natural fine and coarse aggregates by 50% ceramic waste aggregate and 50% RAP, is proposed as the most appropriate sustainable solution. In this way, the use of this asphalt mixture allows for boosting the use of recycled aggregates as well as minimizing the consumption of virgin bitumen due to its residual bitumen content. Compared to the reference asphalt mixture consisting of 100% of natural aggregates, C50R50 is a more open mixture, with higher void content and somewhat more brittleness. Even so, the mixture C50R50 could be good enough for use in low traffic roads.