Rheological properties of cemented gangue backfill material based on fractal characteristics of waste coal gangue

The study herein was intended to evaluate the rheological properties of cemented gangue backfill material (CGBM). For this purpose, the rheological test of CGBM with fractal aggregate particle size distribution was carried out, and variations of static yield stress, dynamic yield stress, and plastic viscosity were investigated as a function of fractal dimension and time. The results reveal that aggregate particle size distribution exerts a significant influence upon the rheological properties of CGBM, and with the escalation of the fractal dimension of the aggregate, the yield stress and plastic viscosity initially decline and then increase. In addition, with elapsing time, the correlation between the static yield stress and the fractal dimension of CGBM specimens increases, while the correlations between the dynamic yield stress and the plastic viscosity and the fractal dimension decrease. The relationships between rheological parameters and fractal dimensions at different times are established based on the experimental results. The influence mechanism of aggregate particle size distribution on CGBM is analyzed from the perspective of the aggregate packing state. This study can provide a basis for the ratio design of CGBM in backfill mining.