Strain rate effect on dynamic mechanical properties and microstructure of cemented tailings composites

The dynamic mechanical properties of the cemented tailings composites (CTC) is one of the major technical challenges in the mining engineering field. In this paper, the Split Hopkinson Pressure Bar (SHPB) impact loading and scanning electron microscopy (SEM) system were conducted to investigate the average strain rate (ASR) rate on the dynamic compressive strength (DCS), microstructure fractal dimension and failure pattern of the CTC specimens. The result shows that the DCS of the CTC increased exponentially with the increase of ASR value when the ASR was in the range of 10-100 s(-1). The main hydrate productions of CTC are C-S-H and AFt. The pore size of CTC increased with increased ASR. The fractal dimension of the pore area increased linearly with increased ASR. According to the above results, it provides a reference for engineers of mine sites to reduce the blasting impact load utilizing discontinuous charging and differential detonation, thus achieving the goal of reducing the dilution rate of underground mining. (C) 2020 Elsevier Ltd. All rights reserved.