3D printing of FRP grid and bar reinforcement for reinforced concrete plates: Development and effectiveness

3D printed concrete has become increasing popular in research and industry communities, while it faces a lack of effective internal reinforcement. Fiber-reinforced polymer (FRP) reinforcement, which has been used widely as reinforcement for concrete structures, has also been adopted to enhance the performance of 3D printed concrete structures. However, conventional FRP manufacturing processes such as pultrusion does not allow on-site forming of the products, leading to difficulties in construction. This paper aims to solve the above issues by developing a novel form of 3D printed continuous fiber reinforced thermoplastic polymers (CFRTPs) reinforcement for 3D printed concrete structures. An experimental program on tensile behavior of 3D printed CFRTP bars and grids was conducted. Then the CFRTP reinforcement was used for 3D printed high-performance concrete to explore the effectiveness of the reinforcement. Twenty-two 3D printed concrete plates were tested to explore the effects of the loading direction and fabrication type on the flexural behavior of FRP reinforced high-performance concrete plates. Results show that the performance of the 3D printed HPC plates can be considerably enhanced owning to the FRP reinforcement and the CFRTP reinforcement are comparable to conventional FRP reinforcement with similar dimensions. This study identifies further research needs on CFRTP reinforcement for construction and will pave the way for studies on 3D printed reinforced concrete structures with both concrete and FRP reinforcement being printed simultaneously.