Cradle-to-Site Life Cycle Assessment of Road Pavement Structures: Effects of Reclaimed Asphalt Pavement, Functional Road Category, and Structural Alternatives

Road pavement construction generates a significant initial carbon footprint, mainly related to material production, transport and construction processes. This study comparatively assesses the “cradle-to-site” carbon footprint of selected road pavement structures, with the aim of supporting low-carbon pavement design choices. The analysis was carried out using the Life Cycle Assessment (LCA) methodology, modelled with the open-source software OpenLCA®, adopting a “cradle-to-site” approach limited to the production and construction phases. Several scenarios were examined by varying the percentages of recycled material content (RAP—Reclaimed Asphalt Pavement) used in asphalt mixtures, the functional road category and the pavement structural type. The results show that the reference flexible pavements produce approximately 70 kg CO2 eq/m2, with asphalt mixtures accounting for the largest share. The use of RAP enables emission reductions of up to 14%, although marginal benefits decrease as the recycled material increases. Impacts also vary according to the functional road category, ranging from approximately 50 to more than 90 kg CO2 eq/m2 when moving from local roads to motorways. Within the adopted cradle-to-site boundary, the LCA model supports the early-stage comparison of alternative pavement designs.