Investigation of the rheological and mechanical properties of 3D printed eco-friendly concrete with steel slag

The primary obstacle to the widespread adoption of 3D printed concrete technology is the high carbon emissions associated with the heavy use of cement in the mixture. The main solutions entail increasing the use of coarse aggregate or identifying suitable cement substitutes. This research explores the potential of utilizing steel slag as a viable substitute for cement. This research evaluates the impact of steel slag content on the rheological and mechanical properties, as well as the ecological impact, of 3D printed concrete. The results show that using up to 10% steel slag improves the buildability of 3DPC. However, the rheological property of 3D printed concrete decreases dramatically when the content is more than 20%. In addition, the weakening of the hydration rate of steel slag will lead to the decline of early mechanical strength, but beneficial to the recovery of later mechanical strength and the reduction of mechanical anisotropy. The incorporation of 20% steel slag effectively reduces the environmental impact and cost of 3D printed concrete, while maintaining its rheological and mechanical properties in the later stage. This study presents a novel type of 3D printable concrete that offers economic and environmental benefits, providing a promising solution for green and low-carbon construction with 3D printed concrete.