Mechanical properties of glass fiber-reinforced backfills under different proportion conditions

Abstract

To investigate the mechanical properties of glass fiber-reinforced backfills under different proportion conditions, uniaxial compression tests were conducted on glass fiber-reinforced backfills with different slurry concentrations (65%, 68%, and 72%) and different cement–tailings ratios (1:6, 1:8, and 1:10). The effects of slurry concentration and cement–tailings ratio on the mechanical performance parameters, failure modes, and energy evolution of the glass fiber-reinforced backfills were discussed, and the effect mechanism of glass fiber on the overall mechanical properties of the backfills was revealed from a microscopic perspective. The results show that the slurry concentration and cement–tailings ratio have significant effects on the elastic modulus and uniaxial compressive strength of the glass fiber-reinforced backfill. The strength of the backfill reaches a maximum value of 2.831 MPa at a slurry concentration of 72% and a cement–tailings ratio of 1:6. The damage of the glass fiber-reinforced backfill under different proportion conditions first appeared in the central low-strength zone, and then gradually extended to the two ends, eventually leading to the overall failure. As the axial strain increases, the total and dissipated energies of glass fiber-reinforced backfill specimens increase as an exponential function, and the elastic energy increases and then decreases with the peak strain as the node. The bond between the glass fiber and the mortar matrix interface allows the fibers across both sides of the crack to form an “anchoring” effect, thus improving the overall properties of the backfill. The results of the study can promote the application and exploration of glass fiber-reinforced backfills in mine filling and provide some reference for improving the backfill performance.