Experimental study on the rheological behavior of ultra-fine cemented backfill

Ultra-fine cemented backfill (UCB) materials display distinctive rheological characteristics. This paper examines the rheological behaviors of UCB composited with cement and tailings that have a 80% cumulative passing size (d((80))) of 9.72 mu m. The findings were that UCB samples exhibit time-dependent non Newtonian behaviors with a shear thinning characteristic, and both thixotropy and rheopexy properties are observed under long periods of steady-state shearing (300 s(-1) shear rate). The results indicate that samples sheared at higher rates display lower apparent viscosities compared to the samples sheared at lower rates. At low shear rates (<= 0.5 s(-1)), apparent viscosity increased until it reached a local peak (or two peaks) before behaving similarly to samples tested at higher shear rates. It was also found that the apparent viscosity of UCB increased consistently as the solids content was increased. Moreover, as cement content was increased, the apparent viscosity rose until it reached a peak at a cement content of 6%. The results also confirmed effects of solids concentration profiles changing over time and the cement hydration on the rheological behavior of UCB. (c) 2017 Elsevier Ltd. All rights reserved.