3D printable engineered cementitious composites for sustainable construction

The automated reinforcement integration in 3D concrete printing (3DCP) encounters many challenges. In this context, a promising solution is offered to address this problem by using engineered cementitious composites (ECC). This strain hardening cementitious composites normally contain a high cement content, especially in 3DCP, increasing the carbon footprint. In this light, this study develops a low-carbon, printable ECC by using industrial waste slag from steel production — the ground granulated blast-furnace slag (GGBS). The GGBS partially replaces the cement content in the original ECC mix design. The influence of 12.5%, 25% and 50% cement replacements with GGBS on either fresh or hardened characteristics of the ECC mortars is experimentally investigated. The flow table and rheological tests indicate that the more GGBS used in the ECC mix design, the more the mortar will be flowable and printable. The 25% cement replacement with GGBS achieves the highest mechanical performance among other mixtures. Higher replacement of cement with GGBS negatively impacts the tensile behavior of the printable ECC mortars. The findings from this study reveal that the sustainable development of printable ECC can be achieved by replacing a certain amount of cement with GGBS, facilitating sustainability in 3D printing construction.