Life cycle evaluation of material transportation impacts in asphalt mixture production

Abstract

This study evaluates the effect of raw material transportation distance and mode – particularly of aggregates – on the Global Warming Potential (GWP) and related environmental indicators during the production stage of bituminous mixtures. Understanding how transport contributes to the life cycle impacts of asphalt mixtures is essential for improving resource logistics and minimising carbon emissions in pavement construction. A Life Cycle Assessment (LCA) was performed using SimaPro software in accordance with the ISO 14040 standards. The analysis considered a representative bituminous mixture composition, including aggregates, bitumen, and filler materials, with varying transport distances and modes (road, rail, and water). Sensitivity analysis quantified the effect of each transport scenario on total GWP at the manufacturing gate. Results indicate that transportation represents a substantial share of total GWP, with outcomes highly dependent on both hauling distance and vehicle type. Reducing aggregate transport distance yields substantial GWP reductions, as halving the road transport distance from 200 km to 100 km decreased total GWP by more than 9%, while long-distance road transport (≥800 km) increased total GWP by over 50%. Among the modes analysed, rail transport exhibited notably lower emissions per ton-kilometre compared with diesel trucking. These findings highlight the critical role of transport logistics in asphalt production and demonstrate that optimising sourcing distances and adopting low-carbon transport modes can significantly reduce the climate impact of road infrastructure.