Effects of curing time and ice-to-water ratio on performance of cemented paste backfill containing ice slag

Abstract

With the continuous development of mining-with-backfill technology, more requirements are proposed for the utilized backfill materials, such as cold-loading, heat-saving, energy-storing, and seepage-proofing. In this paper, a new type of backfill material was proposed by introducing ice into cemented paste backfill (CPB), which is referred as the iced CPB (ICED_CPB) technology. Such an ICED_CPB technology can be used to meet the challenges in hot workplaces that are being frequently encountered as the mining depth increases. The performance of ICED_CPB under the coupled effect of curing time and ice/water ratio (IWR) was investigated experimentally. Some factors affecting the performance of CPB, such as the number of pores (N), porosity fractal dimension (Dc), roundness (RD), permeability (K), unconfined compressive strength (UCS), electrical resistivity (ER) and longitudinal wave velocity (VL) were investigated and their relationships were discussed. The results indicate that the optimum IWR was determined to be 1.2 for the ICED_CPB system in this study. The influence of IWR on N, Dc, K followed a decrease-then-increase pattern while followed an increase-then-decrease pattern on RD, UCS, ER and longitudinal wave velocity. N, Dc, and K increased while RD, UCS, ER and longitudinal wave velocity decreased with increasing curing time.