Green porous pavements for the mitigation of environmental criticalities in urban areas

The rapid growth of urbanisation has intensified the demand for resilient road infrastructure while exacerbating environmental challenges such as the Urban Heat Island effect and urban flooding. Conventional impervious road surfaces contribute to these issues by preventing water infiltration, generating runoff, and consuming vast natural resources. In response, there is increasing interest in sustainable road construction, particularly porous asphalt mixtures incorporating high quantities of recycled materials to create green and blue infrastructure. Porous asphalt is recognised for mitigating surface runoff, reducing flooding, and lowering urban heat effects due to its structure. This thesis investigates the role of porous asphalt concrete as a sustainable pavement solution to address urban challenges, focusing on the incorporation of recycled materials, including Construction and Demolition Waste, Reclaimed Asphalt Pavement, industrial by-products, and biowaste. These materials align with circular economy principles by reducing virgin resource consumption and minimising waste. To evaluate the feasibility of these materials, extensive laboratory investigations assessed their mechanical, physical, and chemical properties. Additionally, a comprehensive Life Cycle Assessment (LCA) quantified the environmental impact. Results showed that recycled materials did not compromise the mechanical properties of porous asphalt. CDW as Recycled Concrete Aggregates (RCAs) enhanced strength and reduced environmental impact. The combination of RAP and Electric Arc Furnace (EAF) steel slags improved mechanical performance in both hot and warm mix asphalt, reducing environmental impacts by 20–40%. A fully recycled cold porous asphalt mix also showed promising results. Furthermore, bivalve shells proved effective as a filler replacement. This research supports the integration of LCA into urban pavement design and aligns with Italy’s Criteri Ambientali Minimi (CAM) guidelines. The findings contribute to the advancement of sustainable urban infrastructure, recommending further studies on durability and Life Cycle Sustainability Assessment (LCSA).