Influence of 3D-printed reinforcement on the mechanical and fracture characteristics of ultra high performance concrete

The current research makes an attempt to examine the possibility of using the 3D printing technique for the reinforcement of Ultra High-Performance Concrete (UHPC). In this regard, the mechanical properties and fracture mechanism of UHPC containing 3D-printed shell reinforcements made from Polylactic Acid (PLA) materials have been investigated. At first, the 3D-printed shell reinforcements were plotted with the aid of 3D Max and Rhino 6 software. Then, they were fabricated through Fused Deposition Modeling (FDM) method and positioned into the cubic, cylindrical and prismatic molds. At the next step, the prepared UHPC mixture was poured into the molds and the samples were cured for 28 days. Finally, the compressive, tensile and flexural strength tests were carried out on the samples. The results indicated that the compressive, tensile, and flexural strengths of reinforced samples were less than the unreinforced ones, respectively. Although the inclusion of 3D-printed reinforcement decreased the mechanical properties of the UHPC samples, it was able to change the fracture mechanism of concrete from brittle to ductile.