Urban mining for low-noise urban roads towards more sustainability in the urban environment

The urban environment faces two challenges: waste and noise. The work presented here shows that the use of certain waste and marginal materials for semi-dense asphalt low-noise pavements is a sustainable option. To this end, mechanical, acoustic and life-cycle assessment evaluations were performed, comparing different scenarios. The results show that these alternative materials can, for the most part, reach the mechanical and acoustic performance required for low-noise pavements both at the binder scale and the mixture scale. Depending on the waste material, mix design adjustments might be necessary such as increasing binder content and the selection of substitution fraction. The results showed that the mechanical performance reached 80% of that of all virgin materials in most cases and the acoustic performance was similar. However, the Technical Readiness Level (TRL) for their use varies and depends strongly on the geographic region. To determine if using alternative materials makes sense in addition to mechanical performance, environmental and economic performance should be considered.