Life cycle assessment of a material-efficient 3D-printed concrete bridge: Comparative sustainability evaluation

Sustainable construction requires reducing both material consumption and environmental impacts. This paper presents a comprehensive cradle-to-gate life cycle assessment (LCA) of a structurally optimized 3D-printed concrete bridge incorporating a material-efficient compression-based form. The bridge is compared with a conventional reinforced-concrete slab designed to have an equivalent flexural capacity and meet code-prescribed deflection limits. The optimized 3DCP bridge reduces concrete consumption by 55% while maintaining comparable structural capacity. Using the structure as the functional unit, the LCA was conducted in accordance with ISO 14040 for stages A1–A5. Although the high cement content of printable concrete increases impacts per unit volume, the material-efficient geometry enabled by 3DCP can offset this higher binder content at the structural level, resulting in lower impacts across several categories. Scenario-based analyses further demonstrate that reducing clinker content can lower the global warming potential below that of the conventional bridge, highlighting the importance of mix optimization.