Experimental study on mechanical properties and bond behavior of wire and arc additive manufacturing steel bar

Wire and arc additive manufacturing (WAAM) technology is a feasible method for manufacturing steel bars to achieve the digital and automatic construction of reinforced concrete structures. However, the bond behavior between the WAAM steel bar and concrete does not meet the requirements of engineering applications. To enhance the bond behavior of the WAAM steel bar, the profiled corrugated steel bar is proposed. In this paper, one group of the natural roughness steel bar and three groups of the profiled corrugated steel bar with varying rib depths were fabricated using WAAM. A comprehensive description of the manufacturing principle and macrostructure of the WAAM steel bar was provided. Additionally, the mechanical properties and bond behavior of the WAAM steel bar were systematically investigated. The results show that the manufacturing precision of the WAAM steel bar can be improved by dynamically controlling the molten pool. The structure of the corrugated rib significantly enhances the bond strength and initial stiffness, with a slight reduction in the equivalent tensile strength and elongation compared to the WAAM natural roughness steel bar. Moreover, the normalized bond strength and initial stiffness of the WAAM profiled corrugated steel bar increase with the increase in rib depth. The experimental curve shows that the five-branch bond stress-slip model developed in this study can evaluate the bond behavior between the WAAM steel bar and concrete satisfactorily.