Study on the Fracture Behavior and Anisotropy of 3D Printing PVA-Fiber-Reinforced Concrete (2024-09)¶

The development of 3D-printing concrete is propelling the advancement of intelligent construction. The application of 3D-printing concrete faces challenges such as difficulty in reinforcing with bars and high brittleness. The incorporation of PVA fibers effectively addresses the brittleness issue of 3D-printing concrete. It is essential to study the fracture properties of PVA fiber-reinforced 3D-printing concrete, which is crucial for the safety of concrete structures. Therefore, this paper carried out the three-point bending test on 3D-printing PVA fiberreinforced concrete (PFRC) beams with four different PVA fiber dosage (0 wt%, 0.1 wt%, 0.3 wt%, and 0.5 wt%) to study its fracture performance and fracture anisotropy. And the digital image correlation (DIC) technology was employed to explore the fracture process in the test. The results indicate that brittleness in the X loading direction is more pronounced than that in the Y and Z loading directions. Additionally, the incorporation of PVA fibers significantly enhances the fracture toughness of concrete. The increase in fracture toughness follows the trend Z > Y > C > X across different loading directions. When the fiber dosage is less than 0.3 wt%, the contribution of the fibers to the crack resistance of the 3D printing PFRC is minimal. At the same fiber dosage, fracture energy, initiation toughness, and instability toughness decrease in the order of Z > Y > C > X loading direction and increase with higher fiber dosage.