Experimental Study of the In-Situ Rebar-Splicing-Technique to Reinforce 3D Printed Concrete in Vertical Directions (2023-08)¶

This study proposed the in-situ rebar splicing technique (ISRST) to address the challenge of vertical continuous reinforcements in the 3D concrete printing. The technique involves splicing inserted rebar segments in stacked mortar layers with high-fluidity material during the printing process. Epoxy resin worked as the experimental splicing material and resulted in successful outcomes. It effectively eliminated visible gaps surrounding the directly inserted rebars and improved the bonding strength to the composite by 315.7%. Pull-out tests concluded that the spliced rebars with 40 mm overlapping performed well, with a splicing ratio of 93.2% and a direct tensile force of 12.52 kN. Moreover, the in-situ-spliced rebars effectively reinforced the cast and printed beams with flexural behavior improvements of 85.8% and 131.6%, respectively. The ISRST was proven successful through simulation and is technically feasible for hybridizing with a 3D printing system to manufacture rebar-reinforced concrete structures.