Toward Low-Carbon 3D Concrete Printing Through Circular Construction and Waste Valorization (2026-01)¶

The construction industry's intensive resource consumption and significant carbon footprint underscore the urgent need for transformative technologies to achieve global sustainability goals. This study conducts a comprehensive cradle-to-grave life cycle assessment (LCA) to compare three-dimensional concrete printing (3DCP) with conventional construction, explicitly integrating waste reuse within a circular economy framework. Six construction scenarios are evaluated using the LCA methodology combined with a novel waste offset model, quantifying environmental impacts across 18 midpoint and 3 endpoint indicators. Monte Carlo simulations are employed to validate the robustness of the results. Findings reveal that the environmental advantages of 3DCP are conditional—substantial benefits emerge only when recycled materials and process optimizations are incorporated. Optimized 3DCP reduces life cycle carbon emissions by up to 53.1 %, while the use of recycled materials offsets as much as 21.8 % of process-related CO2 emissions, aligning with the Global Cement and Concrete Association (GCCA) decarbonization targets. Concrete carbonation during use further cuts 3.92–7.69 % of total carbon footprint. Key constraints affecting 3DCP sustainability include high cement content, transportation energy demand, and dependency on chemical admixtures. The study highlights targeted material optimization, energy-efficient process design, and supportive policy measures as critical pathways for advancing 3DCP toward net-zero construction, thereby providing theoretical support for the construction, 3D printing, and environmental protection industries.