Investigation of Viscoelastic-Plastic Properties of Fresh Cemented Gangue Fly Ash Backfill Slurries

Abstract

In underground filling mining, freshly prepared cemented gangue-fly ash backfill (CGFB) slurries are typically piped into the gobs. The rheological properties of backfill slurry during pipeline transportation have a direct impact on the transportation characteristics, which in turn affect pipeline blockage and wear. In this paper, the rheological behavior and viscoelastic-plastic properties of CGFB during pipeline transportation are investigated. The effects of different solid content and cement content on resistivity were tested experimentally, and their viscoelasticity and plasticity were analyzed. The results show that with the increase in solid phase content and cement content, the viscosity, yield stress, and energy storage modulus of the materials showed an increasing trend. The viscosity and yield stress of the material both increased, reaching 32.77% and 51.22%, respectively. It was found by the dynamic shear test that in the low-strain region, the material showed a more significant elastic nature of the solid, while in the high-strain region, the viscosity of the material gradually increased. Cement has a substantially lower resistivity than fly ash and gangue, and with the increase in solid concentration, the resistivity of the material shows an increasing trend. With the increase in cement content, the resistivity generally shows a decreasing trend, but it should be noted that the resistivity change trend may tend to stabilize after the cement content exceeds 12%. The study’s findings can aid in understanding the rheological properties of CGFB and its viscoelastic-plastic behavior during the underground filling and conveying process, which can provide a reference basis for research and application in related fields.