Environmental assessment of large-scale 3D printing in construction: A comparative study between cob and concrete

This paper explores the environmental impacts of large-scale 3D printing (3DP) construction in comparison to conventional construction methods using two different types of construction material: concrete and cob (a sustainable earth-based material). The study uses a standard Life Cycle Assessment (LCA) method, from cradle to site, to assess the environmental impacts of the construction materials and processes, with a focus on load-bearing walls in small/medium size houses. As expected, cob-based methods (conventional followed by 3DP) show lower overall environmental impacts and global warming potentials than the concrete-based methods. The study also shows that while the overall environmental impacts of 3DP concrete is higher than that of 3DP cob due to higher global warming potential, stratospheric ozone depletion and fine particulate matter formation, it has less impact on marine eutrophication, land use, and mineral resources scarcity. The environmental issues that remain to be overcome in relation to 3DP concrete is its high-cement content, while the issue in 3DP cob rises from the use of electricity for the 3D printing operation. The study indicates that the use of renewable energy resources and innovative material science can greatly increase the potentials of both 3DP cob and 3DP concrete respectively for future construction. (C) 2020 Elsevier Ltd. All rights reserved.