Barbed-wire reinforcement for 3D concrete printing

3D-printing has been growing in acceptance in the construction industry owing to its transformative potential in concrete materials. One of the main challenges for its further adoption is the integration of reinforcement given the difficulty of incorporating steel rebars and the formation of cold joints between filaments. This study proposes the use of barbed wires, fencing wires with sharp thorn-like projections, as a reinforcing component to improve tensile capacity and bond between printed filaments. Results indicated that incorporating barbed wire into 3D-printed concrete increases overall mechanical performance (e.g., moment capacity and bond strengths up to 363% and 71%, respectively, compared to plain 3D-printed concrete). This improvement can be attributed to the twisting of wires and the unique geometry of the 4-point barbs. The proposed barb-wire reinforcement method demonstrates the feasibility of in-process reinforcing during 3D-printing and can be further advanced to achieve full automation of the printing and reinforcement processes.