Influence of silica fume on mechanical property of cemented paste backfill

The cemented paste backfill (CPB) method, which is the most preferred method for tailings storage, is one of the most used methods for the disposal of mine tailings. However, the high rate of cement usage increases the costs. In this study, whether silica fume (SF), which is a pozzolanic material, can be used as a substitute instead of cement was investigated based on mechanical parameters or not. As a result of the experiments, it was determined that SF substituted for portland cement (PC) increased the strength of paste backfill mixtures prepared in a certain cement ratio. In addition, it was determined that SF substitution in CPB increased the durability of mixtures against sulphate attacks as it did in concrete. With the use of SF, savings of up to 20% were achieved in the amount and cost of cement used in CPB. Besides, using it without the pulverizing process required for pozzolanic materials used in other studies had a positive effect in terms of time and cost. Moreover, the use of SF in CPB mixtures resulted in less energy use and less greenhouse gas emissions, and a reduction of environmental pollution caused by SF tailings.