Automated reinforcement of 3D-printed engineered cementitious composite beams

The advancement of emerging 3D concrete printing (3DCP) has been hindered by two significant challenges: the weak tensile properties of conventional concrete and the difficulty of simultaneously placing reinforcement during printing. In this paper, engineered cementitious composites (ECC) with superior tensile properties along with an in-process reinforcement technique through laying CFRP meshes between ECC layers were strategically composited. Four-point bending tests were performed on 3DP-ECC beams reinforced with different layers and configurations of CFRP mesh. Experimental results demonstrated that CFRP meshes can deform collaboratively with ECC, and enhance the load bearing capacity of 3DP-ECC beams to 1.22-2.01 times compared to that of unreinforced beam, while moderately decrease the deformation capacity of printed beams. A theoretical model for predicting the load bearing capacity and bending moment-curvature relationship of 3DP-ECC beams was further proposed. This paper validated the feasibility and effectiveness of CFRP mesh in reinforcing 3DP-ECC beams for efficient 3DCP construction.