No abstract

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 loadbearing 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 highcement 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.

No abstract

This paper investigates the thermal properties of 3D printed Cob, a monolithic earth construction technique based on robotically extruded subsoil and locally available organic fibres. The relevance of 3D printed earthen construction materials and the transition from vernacular construction towards a digitally-enabled process are critically discussed. The use of robotic manufacturing is outlined and the methodology to produce the necessary samples for thermal measurement is detailed. The results of the 3D printed samples are compared with traditionally-constructed Cob material of the same dimensions. The assessment has revealed strong potential for 3D printed cob as compared to its manually constructed counterparts in terms of thermal conductivity. Moreover, the testing process has helped in identifying several challenges in the 3D printing process of cob and the assessment of its thermal properties, which will ultimately bring the work closer to full-scale applications.