State-of-the-art of 3D printing technology of cementitious material-An emerging technique for construction

In recent few years, significant improvement has been made in developing largescale 3D printer to accommodate the need of industrial-scale 3D printing. Cementitious materials that are compatible with 3D printing promote rapid application of this innovative technique in the construction field with advantages of cost effective, high efficiency, design flexibility and environmental friendly. This paper firstly reviews existing 3D printing techniques that are currently being used in commercial 3D printers. It then summarizes three latest development of largescale 3D printing systems and identifies their relationships and limiting factors. Thereafter, critical factors that are used to evaluate the workability and printable performance of cementitious materials are specified. Easy-extrusive, easy-flowing, well-buildable, and proper setting time are significant for cementitious material to meet the critical requirements of a freeform construction process. Finally, main advantages, potential applications and the prospects of future research of 3D printing in construction technology are suggested. The objective of this work is to review current design methodologies and operational constraints of largescale 3D printing system and provide references for optimizing the performance of cementitious material and promote its responsible use with largescale 3D printing technology.