Characterization of the Mechanical Properties of Fiber-Reinforced Modified High Water Content Materials

This research examines the mechanical properties of fiber-reinforced modified high-water content materials intended for mining backfill applications. Conventional high-water content materials encounter several challenges, including brittleness, inadequate crack resistance, and insufficient later-stage strength. Basalt fiber (BF) and polypropylene fiber (PP) were integrated into the material system to establish a reinforcing network through interfacial bonding and bridging mechanisms to mitigate these issues. A total of nine specimen groups were developed to assess the influence of fiber type (BF/PP), fiber content (ranging from 0.5% to 2.0%), and water cement ratio (from 1.25 to 1.75) on compressive, tensile, and shear strengths. The findings indicated that basalt fiber exhibited superior performance compared to polypropylene fiber, with a 1% BF admixture yielding the highest compressive strength of 5.08 MPa and notable tensile enhancement attributed to effective pore-filling and three-dimensional reinforcement. Conversely, higher ratios (e.g., 1.75) resulted in diminished strength due to increased porosity, while a ratio of 1.25 effectively balanced matrix integrity and fiber reinforcement. Improvements in shear strength were less significant, as excessive fiber content disrupted interfacial friction, leading to a propensity for brittle failure. In conclusion, basalt fiber-modified high water content materials (with a 1% admixture and a ratio of 1.25) demonstrate enhanced ductility and mechanical performance, rendering them suitable for mining backfill applications. Future investigations should focus on optimizing the fiber matrix interface, exploring hybrid fiber systems, and conducting field-scale validations to promote sustainable mining practices.