Mechanical behavior of FRP sheets reinforced 3D elements printed with cementitious materials

A method to improve the mechanical behavior of 3D-printed elements is presented. 3D-printed elements are orthotropic and weak in their interlayers; thus, FRPs, which are easy-formed, light-weighted and high-strength, are ideal materials to enhance 3D-printed elements. To investigate the reinforcement effect, uniaxial compression tests were conducted on circular column specimens, and four-point flexural tests were conducted on beam specimens. The results indicated that wrapping 3D-printed columns with FRPs changed their failure modes from brittle to ductile, increased the peak loads that they could endure by 1427.2–1792.0% and increased the largest deformations they could achieve by 833.9–1171.3% using different numbers of layers and types of reinforcement. For the 3D-printed beams reinforced with FRPs, the bearing capacities were increased by 179.6–604.5%, and their flexure deflections at their mid-spans were increased by 40.8–225.8%. The failure modes of the 3D-printed beams were affected by numbers of layers and types of reinforcement. Additionally, finite element analyses were conducted to simulate the failure modes of the 3D-printed elements based on the maximum stress criterion. The results showed that the predicted failure locations corresponded with the experimental failure locations observed. According to this study, 3D-printed elements reinforced with FRP sheets showed potential for future development and applications in construction.