Construction Techniques for Lowering Embodied GHGs: A Review of Prefabrication and 3D Printed Concrete Mix Designs

Abstract

With ongoing global urbanization, the construction industry has been steering towards adopting automated construction techniques to enhance efficiency and quality in production with the expectation of lowering greenhouse emissions (GHGs). However, there is a limited understanding of the impacts of using these techniques on GHGs. This thesis investigates two such techniques, prefabrication and 3D printing. It assesses the embodied GHGs of prefabricated buildings and 3D printed concrete (3DPC) mixes and compares them with that of conventional counterparts. A meta-analysis of published life cycle assessment results from prefabricated buildings and a detailed analysis of published 3DPC mixes are undertaken in this research. The findings suggest more similarity in terms of embodied GHGs between prefabricated and conventional buildings than widely reported. Results also show that 3DPC mixes usually have higher emissions compared to cast-in-place concrete due to having higher cement contents, though they also have lower emissions per unit of strength.