3D Printed Concrete Composite Slabs Fabricated by Pre-Stressed Reinforced Permanent Formwork (2024-12)¶

To promote the application of 3D printing in large-span structural engineering, this paper proposes a 3D-printed reinforced structure with prestressed permanent formwork (PR-3DCPPF). This innovative approach combines post-tensioning prestressing technology to achieve the assembly construction of large-scale permanent formwork structures, thereby enhancing the construction efficiency, flexibility, and load-bearing performance of 3D printing structures. This study designed and digitally fabricated a 3D-printed a PR-3DCPPF slab structure with a length of 6.0 m, comprising six identical 3D printing formwork units. These formwork units were independently printed, assembled through post-tensioning prestressing, reinforced with cage reinforcement and concrete casting, and then the entire structure was collaborative working by prestressed formwork and cast-in-place concrete. The load-carrying capacity and prestress loss of the formwork unit were assessed post-tensioning, and the flexural performance of the printed composite slab structure was tested across various stages, confirming compliance with structural standards. The experimental validation demonstrates that the proposed structure exhibits a deflection-to-span ratio of less than 0.1 % during the service stage and an ultimate loadbearing capacity exceeding 141 kN, proving its excellent mechanical performance.