A Critical Materials Perspective on 3DCP: Extractive Practices and Environmental Scalability in AM for Construction

The current state of the art in assessing the environmental impact of 3D Concrete Printing (3DCP) technologies has focused especially on the material impacts, given the known issues posed by concrete. By contrast, 3DCP machinery impacts remain mostly unknown, with only few studies examining the equipment necessary to additive manufacturing and evaluating their impact with Life-Cycle Assessment (LCA) techniques. Taking point of departure in 3DCP as a case study, the research examines the usual assumption in the construction industry that materials impacts outweigh significantly machine impacts and that the latter can therefore remain out of scope of standard LCAs of buildings and building products. Assessing different concrete additive manufacturing (3DCP) wall typologies and focusing on the amounts of critical materials present in the system, the research compares the presence of such resources in the material and the set-up as well as the consequences for abiotic depletion and the scaling up of AM practices in the AEC industry (Architecture, Engineering and Construction). Highlighting the risk of significant impact transfer in some of the evaluated scenarios, the research advocates for a systematic impact of machinery impacts in 3DCP.