Understanding the role of supplementary cementitious materials in 3D printed concrete

Three-dimensional (3D) concrete printing has emerged as a transformative construction technology; however, its sustainable deployment hinges critically on supplementary cementitious materials (SCMs), whose comprehensive effects on printability, buildability, mechanical performance and durability have not been systematically assessed. Although a growing body of research has been conducted to examine individual SCM substitutions, such as fly ash, ground granulated blast-furnace slag, silica fume, rice husk ash and limestone, these studies often treat material performance in isolation and lack a cohesive analysis linking SCM physicochemical characteristics to fresh-state rheology and hardened properties. To bridge this gap, a structured review has been conducted, highlighting key challenges and mitigation strategies. Durability outcomes are analysed to determine the influence of SCM type and dosage on long-term performance. This synthesis reveals critical interdependencies between SCM properties and extrusion, setting time, strength and durability. Finally, pressing research needs are identified to guide future investigations aimed at advancing sustainable 3D printed concrete.