Cradle-to-Pavement Carbon Footprint of Bio-Extended Bitumen

The carbon footprint of bio-extended bitumen aiming for pavement decarbonisation was quantified using a ‘cradle-to-pavement’ Life Cycle Assessment. The bitumen was extended with a plant-based bio-oil, which is refined from the by-products of the pulp and paper industry. The results indicated that using the bio-oil as a bitumen extender slightly increases the fossil Global Warming Potential (GWP) of asphalt pavements up to the construction phase of the life cycle, by about 1%. By biogenic GWP accounting, the impact of biogenic carbon is analysed regarding the inbound transfer from the previous product systems. For a pavement structure with two asphalt layers using bio-extended bitumen, the biogenic GWP reduction due to inbound transfer of biogenic carbon accounted for more than 50% of the fossil GWP. However, the impacts of the outbound transfer and eventual emissions of biogenic carbon still need to be assessed in future studies to cover the complete biogenic carbon flow.