Enhancing bending performance of cemented lithium feldspar tailings backfill with 3D printing polymer lattices: Effects of unit shapes and materials

To comprehensively test and analyze the effects of three-dimensional printed polymer lattice (3DPPL) on the bending performance of cemented lithium feldspar tailings backfill (CLFTB) specimens, this study conducted three-point bending test on 3DPPL-reinforced CLFTB (3DPPLRCLFTB) specimens prepared with different unit shapes: cube (CU), hexagonal prism (HE), octagon (OC) and materials: white resin (WR), black nylon (BN), transparent resin (TR). The results indicated that WR performed best in enhancing the strength of CLFTB, while TR was most effective in improving toughness, with OC was the optimal unit shape. The maximum strength and maximum deflection of 3DPPL-RCLFTB reached 5.961 MPa and 28.84 mm, respectively, representing increases of 2.75-3.74 times and 24.06-27.78 times compared to the control group (N-3DPPL-RCLFTB). All 3DPPL-RCLFTB specimens exhibited superior bending performance and ductility, with 3DPPL effectively prolonging the destruction process and significantly improving stability. The incorporation of 3DPPL transformed the destruction mode of CLFTB from a single crack destruction mode to a multiple crack destruction mode, shifting from brittle to ductile destruction. The maximum strain value on the surface of the 3DPPL-RCLFTB specimens was 36.343 %, with the TR-OC-3DPPL-RCLFTB showing the best multiple crack destruction mode.