Coupled Effects of Time and Temperature on the Rheological and Pipe Flow Properties of Cemented Paste Backfill

As mineral resources at shallow depths become increasingly depleted, the development of these resources is progressively shifting to greater depths. This transition presents challenges for the pipeline transport of cement paste backfill (CPB), particularly in terms of long-distance transport and elevated temperatures. To investigate this phenomenon, we conducted rheological tests, developed a resistance model that accounts for both time and temperature, and performed numerical simulations. The results show that the rheological parameters of CPB exhibit a gradual decline as the flow progresses. Specifically, at 20 °C, the plastic viscosity of CPB decreases by 1.6 Pa·s, and the yield stress decreases by 48.15 Pa; at 30 °C, the plastic viscosity decreases by 1.3 Pa·s, and the yield stress decreases by 18.69 Pa; at 40 °C, the plastic viscosity decreases by 0.84 Pa·s, and the yield stress decreases by 12.55 Pa; and at 50 °C, the plastic viscosity decreases by 0.58 Pa·s, with the yield stress decreasing by 12.53 Pa. Furthermore, the influence of shear time on the rheological properties of CPB diminishes as temperature increases within the range of 20 °C to 50 °C. These results offer significant insights for optimizing the pipeline transport of CPB in mining operations. These findings provide valuable guidance for pipeline transport of CPB in mining operations.