Experimental investigation of effect of cement content and sulphate concentration on loading rate-dependent fracture behaviour of CPB under Mode I, II, and III loading conditions

Abstract

Cement paste backfill (CPB) technology is becoming the standard mine backfilling approach in the mining industry as an environmentally friendly and cost-effective way to manage tailings. Most importantly, CPB plays a critical role in ground support to the surrounding rock mass to ensure the safe and effective operation of the mine. After placement into the mined-out voids, the CPB structure is subjected to complex loading conditions. Due to the dependency of mechanical behaviour on the loading rate, CPB may demonstrate distinctive response and fracture failure characteristics under field loading conditions. However, previous research has primarily concentrated on traditional geomechanical behaviours, ignoring the impact of loading rate on the fracture behaviour of CPB, which significantly influences the assessment of mechanical behaviour and performance of in-stope CPB. Meanwhile, as a cementitious composite, the chemical factors, including cement content and sulphate concentration, dominate the evolution of the mechanical properties of CPB. Therefore, it is of theoretical and practical importance to investigate the effects of cement content and sulphate concentration on CPB's loading rate dependent fracture behaviour. The research aims to evaluate the loading rate dependent fracture behaviour and properties of CPB under different loading conditions. [...]