Rheological properties of a multiscale granular system during mixing of cemented paste backfill: A review

The technology of cemented paste backfill (CPB) is an effective method for green mining. In CPB, mixing is a vital process aiming to prepare a paste that meets the non-stratification, non-segregation, and non-bleeding requirements. As a multiscale granular system, homogenization is one of the challenges in the paste-mixing process. Due to the high shearing, high concentration, and multiscale characteristics, paste exhibits complex rheological properties in the mixing process. An overview of the mesomechanics and structural evolution is presented in this review. The effects of various influencing factors on the paste's rheological properties were investigated, and the rheological models of the paste were outlined from the macroscopic and mesoscopic levels. The results show that the mechanical effects and structural evolution are the fundamental factors affecting the rheological properties of the paste. Existing problems and future development trends are presented to change the practice where the CPB process comes first and the theory lags.