Life Cycle Assessment of Asphalt Mixtures Incorporating Secondary Raw Materials Under a Circular Economy Perspective

The road construction sector is increasingly striving to reduce its environmental footprint while advancing circular economic goals. Conventional asphalt mixtures depend on virgin aggregates and bitumen, which significantly contribute to emissions and resource depletion. This study addresses the issue by assessing the environmental performance of asphalt mixtures incorporating secondary raw materials—reclaimed asphalt, recycled fishnets, and cellulose fibres. A cradle-to-gate life cycle assessment was conducted on four mixtures, using the ReCiPe 2016 Midpoint (H) impact assessment methodology. The results along with the hotspot and sensitivity analyses show that reclaimed asphalt offers the most consistent environmental benefits, notably mitigating climate change and resource depletion impacts by replacing virgin aggregates. Recycled fishnets, despite addressing marine plastic waste, showed higher toxicity and eutrophication burdens due to energy-intensive processing. Cellulose fibres reduced climate impacts but increased land use and terrestrial ecotoxicity. Results highlight that the environmental benefits of introducing recycled materials are incremental rather than transformative at the production stage, and that the influence of supply-chain logistics can outweigh differences among mixtures. Although the cradle-to-gate perspective provides valuable insights for material selection and procurement, future studies should include use and end-of-life phases, where larger environmental benefits may emerge for certain mixtures.