Strength and Ductility Enhancement of 3D Printing Structure Reinforced by Embedding Continuous Micro-Cables (2020-07)¶

3D concrete printing (3DCP) is used to manufacture freeform components by digitally controlling the distribution of concrete materials without requiring additional formwork. Recurring issues associated with 3DCP are low tensile strength and poor ductility of the nonreinforced structures. In this paper, a reconciliation printing methodology is presented for manufacturing reinforced geopolymer structures by simultaneously embedding micro-cables during the printing process. Structural arched beam and spiderweb-like structures were 3D printed and used to verify the feasibility of the proposed reinforcing method by evaluating their shape-based structural performance. A self-developed loading device was used to simulate the natural tension-only stress condition of a real spiderweb. The loading capacity of the cable-reinforced web structure was calculated and compared to the test results, which verified the bonding and the reconciliation between the micro-cable and the geopolymer matrix. As compared to the nonreinforced structures, the failure mode of the reinforced structures changed from brittle to ductile with multiple cracks, and the micro-cable reinforcement altered the strain evolution patterns. This study demonstrates that the strength of the reinforced structure was substantially increased. Further, both the method of reinforcement and the specific configuration of the 3D printed structures play a crucial role in resisting deformation and damage.