Flexural performance of concrete beams via 3D printing stay-in-place formwork followed by casting of normal concrete

Abstract

In traditional mold-casting for concrete, the process of assembling and demolding formwork is both costly and time-intensive, limiting the design possibilities of complicated shaped and composite applications. Autonomous or semi-autonomous 3D concrete printing presents an innovative solution, allowing for the customization of intricate formwork shapes and facilitating the creation of composite structures. This study develops and manufactures a novel concrete beam that incorporates 3D-printed (3DP) ultra-high performance strain-hardening cementitious composites (UHP-SHCC) U-shaped jackets used as stay-in-place formwork, with normal concrete (NC) as filled concrete. To evaluate the flexural performance of the proposed beam, composite beams with cast-in-place formwork and post-cast NC, fully cast NC beams and fully cast UHP-SHCC beams are also tested. The flexural performance of these beams is assessed through four-point bending tests, including failure modes, load–displacement response, and cracking behavior. Results indicate that concrete beams utilizing 3DP UHP-SHCC stay-in-place formwork demonstrate superior flexural performance, characterized by deflection-hardening behavior, outperforming the other tested configurations.

Keywords:

• 3D concrete printing
• stay-in-place formwork
• ultra-high performance strain-hardening cementitious composites (UHP-SHCC)
• flexural behavior
• concrete beam

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Hong Kong Research Grants Council under Grant 27209020 and 17204322.