Circularity and life-cycle assessment of a temporary bridge in Portugal

Bridge infrastructure is increasingly approaching the end of life, yet bridge Life Cycle Analysis rarely examines how end-of-life (EoL) assumptions influence environmental performance. Special emphasis is placed on the potential reuse of bridge components at the EoL stage. This study assesses the circularity of a temporary steel-concrete composite overpass in Portugal, with emphasis on alternative EoL pathways. The LCA follows ISO 14040/14044 and EN 17472 and covers the product stage (A1-A3), construction (A4-A5), end of life (C1-C4), and benefits and loads beyond the system boundary (Module D). Two main EoL scenarios are compared: material recycling and component reuse, complemented by sensitivity analyses on deck reuse (Reuse+) and low-carbon emission materials. Inventory data were derived from a BIM model developed from original drawings. Results show that A1-A3 dominates embodied impacts, contributing about 85% of Global Warming Potential - total (GWP T ) over stages A-C. Recycling and reuse give nearly identical embodied results up to the end of life (429,24 vs. 429,39 kg CO₂eq./m 2 ), but reuse provides higher net benefits in Module D, mainly through the avoided production of recovered steel components. Extending reuse to the prefabricated deck further increases these benefits, while low-carbon materials reduce A-C impacts by up to 39%. The latter, however, also reduces the magnitude of Module D credits, highlighting the need for whole life-cycle interpretation. The results show that low-carbon material specification and reuse-oriented EoL strategies are complementary, and that mass-based circularity indicators alone are insufficient to identify environmentally preferable EoL options.