Sustainable bridges – LCA for a composite and a concrete bridge

Abstract

Life Cycle Assessment addresses the environmental impacts of a product’s life cycle, from raw material extraction through production, use and end-of-life. In this paper, we apply this standardized method to two bridges: one designed as a composite bridge and one as a prestressed concrete bridge. The environmental profile of the bridges, defined by eleven indicators, is strongly connected to the bill of quantities. As a result, the composite bridge generates significantly less environmental impacts than its equivalent made of prestressed concrete, much heavier. The study also demonstrates that recycling is not necessarily beneficial depending on the material. On the one hand, the recycling of structural steel avoids the emission of 32 tCO2eq, thus decreasing the overall impact of the composite bridge, and, on the other hand, reinforced concrete requires a pre-treatment before recycling that is not counterbalanced by the benefits of recycling, thus downgrading the overall environmental profile of the prestressed bridge.