Substitution of cement by marine clay in spray-based 3D concrete printing

Spray-based 3D concrete printing (S-3DCP) is a type of 3D concrete printing specifically for automated constructions on vertical and overhanging surfaces, e.g. facades and ceilings. In this study, cement is partially substituted by calcined marine clay to develop a high-performance mixture for S-3DCP. Through setting, rheological, and tack tests, the fresh properties of the mixtures with marine clays calcined after different temperatures have been assessed. Considering pumping and deposition performance, tackiness, and sustainability, the optimum calcination temperature of marine clay is determined as 700 °C. The subsequent spray-based printing test shows that compared with the mixture without marine clay, the mixture with the marine clay calcined at 700 °C has a more uniform thickness distribution and 185% higher building capacity. The study contributes to the deeper understanding of the rheological and tack properties of the mixtures with calcined marine clay, which guides the future utilization of marine clay.