Comparative life cycle assessment of a novel sustainable road pavement system adopting recycled plastic from PET bottles and carbonated aggregate

Abstract

Road surfacing is crucial in improving community accessibility and mobility. Adopting sustainable measures is extremely important to prevent the significantly high environmental burdens associated with road pavement systems production. This study presents a comparative life cycle assessment of traditional pavement systems and their sustainable alternatives made and tested at the London South Bank University laboratories. The low-impact pavement mixes proposed herein provide a novel, innovative method for producing sustainable road systems. Unlike traditional approaches, these asphalt mixes utilise materials derived from recycled polyethylene terephthalate (plastics) and carbonated aggregates and are produced at temperatures significantly lower (warm mix).The Simapro software (Consultants, 2023) [1] was used to model the analysed asphalt mixes, and all life cycle inputs and outputs were characterised during the life cycle impact assessment phase into potential impacts using the IMPACT World + Midpoint method. Additionally, an uncertainty analysis employing Monte Carlo simulation was conducted to validate the life cycle assessment findings, reinforcing the robustness and credibility of this study's results. Notably, the assessment shows substantial reductions in the environmental impact of road pavement mixes adopting recycled plastic and carbonated aggregates, with various outcomes. Compared to traditional mixes, Climate Change emissions are reduced by approximately 40 %–60 %, Marine Eutrophication exhibits reductions of up to 30 %, and Freshwater Eutrophication decreases by up to 20 %. These findings suggest that integrating this sustainable road pavement approach can significantly reduce the environmental burdens of asphalt production and give asphalt a pivotal role in tackling waste reduction, carbon sequestration, and achieving Net Zero. Also, the proposed system can positively contribute to the current United Kingdom's (UK) circular policy model by reconsidering current waste management frameworks and integrating more efficient settings.