Abstract
Concrete is a popular building material that is frequently used in a wide range of applications such as bridges, buildings, and roads. While concrete is strong in compression, its brittle behavior makes it dangerous as it may fail abruptly without warning. Typically, steel rebars are used as reinforcement to enhance ductility of concrete. However, steel rebars can be expensive, heavy, and susceptible to corrosion. With the advancements in 3D printing technologies, 3D printed lattice structures may offer alternative potential benefits as a reinforcement to concrete compared to steel rebars such as design flexibility, cost-effectiveness, and resistance to corrosion. This thesis focuses on a specific type of lattice structure known as the gyroid pattern due to its unique spiral geometry, that allows for concrete to infiltrate. The gyroid lattice structure designs were 3D printed with polylactic acid (PLA) material and placed into rectangular and cube molds and filled with ultra high-performance concrete (UHPC). These gyroid lattice-reinforced UHPC specimens were then tested in compression and three-point bending to study its material properties. Compression results show that cubes with density infill percentages had a 72-73% decrease in compressive strength compared to UHPC cubes without reinforcement but displayed high ductility. Bending test results show that the gyroid beam infill models with 7% density exhibit toughness levels about 10.9 times greater than UHPC beams without reinforcements.