In-process reinforcing method: dual 3D printing procedure for ultra-high performance concrete reinforced cementitious composites

• Published in: Materials letters 2021-12, Vol.304, p.130594, Article 130594
• Main Authors: Bai, Gang, Wang, Li, Wang, Fang, Ma, Guowei
• Format: Article
• Language: English
• Subjects: 3-D printers; 3D concrete printing; Bend strength; Composite materials; Concrete; Deformation and fracture; Ductile-brittle transition; Failure modes; In-process 3D concrete printing reinforcement; Materials science; Mechanical properties; Reinforced concrete; Reinforcement; Thin plates; Three dimensional printing; Toughness improvement; Ultra high performance concrete
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2021.130594

•In-process 3D printing reinforcing method for UHPC reinforced concrete (3DP-UHPCRC) is proposed.•The 3D printing equipment for dual concrete materials is developed.•Significant improvement of mechanical properties of 3DP-UHPCRC compared to ordinary 3DPC counterpart is demonstrated. The general application of 3D printed concrete (3DP-C) in practical engineering is significantly hindered by the lack of adequate reinforcement procedures, which is an intrinsic limitation of the 3D printing process. To address this limitation, this study proposes an in-process dual-printing reinforcement method, which concurrently and continuously prints ultra-high performance concrete (UHPC) and ordinary 3DP-C. The UHPC, as an integral part of the printed structure, serves as reinforcement for the overall concrete composite. Printing equipment for these dual concrete materials is developed to realize the coordination of the dual-material deposition process. Significant improvement of mechanical properties of 3D printing UHPC (3DP-UHPC) reinforced 3DP-C, which is then abbreviated as 3DP-UHPCRC, is demonstrated through four points bending tests of thin plate specimens. In comparison to plain 3DP-C, the reinforced concrete possesses an 160.5% increase in ultimate bending strength as well as a brittle to ductile bending failure mode transition, thus demonstrating the effectiveness of the proposed reinforcement method.