Effects of Silica Fume on the Performance of Cemented Paste Backfill Mixed with Brine

Brine water as a filling affected the strength of the filling body in Sanshandao Gold Mine, because it introduced higher concentrations of Cl−, SO42−, Mg2+ and other ions. In this paper, the effect of brine on the strength of cemented paste backfill and the mechanisms of micro-corrosion were studied. The effect of silica fume on the corrosion resistance of brine ions in cemented paste backfill was also studied. The influence of bittern ions on cemented paste backfill was analyzed using scanning electron microscopy and X-ray diffraction. Chloride permeability, capillarity coefficient, shear stress and viscosity and shear rate are obtained through the capillary water absorption test, rapid chloride permeability test, compressive strength test, direct shear test, and rheological test of cemented paste backfill. Then the mechanism for improving the brine corrosion resistance of the filling body with silica fume was analyzed. The results show that there was an improvement in the bittern corrosion resistance and other properties of the cemented paste backfill when the content of silica fume was 8% by weight.