Environmental life-cycle impacts of bitumen: Systematic review and new Canadian models

Abstract

Bitumen − or asphalt binder − is a major contributor to pavement environmental impacts. Nevertheless, the literature only counts scarce asphalt binder LCAs, with highly variable results. To better understand bitumen environmental impacts, we review LCAs published before 2024. Then, we build bitumen LCA models for different Canadian markets, using TRACI 2.1 and ecoinvent v3.6. The carbon footprint of Canadian asphalt binders ranges within [826–1098] kgCO₂eq/t (potentially up to 2680 kgCO₂eq/t when including fugitive emissions). Crude oil extraction is the main contributor to most life cycle environmental impact categories, but likely still underestimated. Transportation impacts can vary highly ([18–291] kgCO₂eq/t in Canada). Models for these two hotspots must be tailored. Finally, we critically compare the carbon footprints of all published virgin asphalt binders LCAs: previous carbon footprints range within [143–637] kgCO₂eq/t and are very likely underestimated. Previous pavement LCA results must be questioned, and higher-quality LCIs urgently developed to produce robust regionalized LCA-based recommendations on pavement green practices.