Evaluating glass powder substitution for 3D printed concrete: effects on thermal properties and embodied carbon

The construction industry faces increasing pressure to reduce its environmental footprint through improved materials and construction practices. This study investigates the use of ultra-fine glass powder (UFGP) as a partial cement replacement in reactive powder concrete (RPC) for 3D-printed concrete (3DPC), focusing on thermal performance and embodied carbon reduction. Six mix designs with UFGP replacement levels up to 25 % were evaluated. Experimental results show that substituting 5 % of cement with UFGP reduces thermal conductivity by 10.9 %, enhancing the material’s insulation capacity. EnergyPlus simulations for a residential building in Shanghai indicate a potential annual energy savings of 2.6 MJ/m² (4.85 %) with 5 % UFGP-enhanced concrete, arising from the synergistic effects of reduced thermal conductivity and increased thermal mass. Although the high binder content (1000 kg/m³) remains a limitation of current 3DPC technology, partial cement replacement with UFGP presents a viable strategy for lowering embodied carbon while improving thermal performance. These results demonstrate the potential of UFGP to advance next-generation sustainable construction by enhancing energy efficiency and reducing embodied carbon in 3D-printed concrete applications. However, further investigation is needed to validate performance across a wider range of environmental and structural conditions.