Greenhouse gas emission of recycled concrete production for pavement construction considering carbon uptake

The carbonation or uptake effects are often ignored when quantifying the greenhouse gas (GHG) emissions from recycled concrete production, resulting in a neglected balance between carbon emissions and absorption. This study specifically considers these effects using the life cycle assessment (LCA) methodology to quantify GHG emissions from recycled concrete used for pavements. The cradle-to-gate LCA includes raw material extraction, transportation, production, and carbonation during mixing and curing. The findings indicate that (1) the net GHG emissions of recycled concrete are lower than those of virgin concrete, with higher recycled coarse aggregates (RCA) replacement rates leading to further emission reductions. (2) carbonation during the production phase significantly contributes to carbon capture, thus reducing the overall GHG emissions. (3) recycled concrete has lower environmental costs and requires less green area for carbon absorption than conventional concrete, highlighting the environmental and economic benefits of using recycled concrete in pavement construction. • Using LCA methodology quantifies GHG emissions and carbon uptake of recycled concrete aggregate & concrete. • The carbonation of recycled concrete at production stage can effectively capture carbon. • Higher RCA replacement rates reduce emissions (case study). • Recycled concrete offers environmental and cost benefits.