The effects of temperature and binder content on the behavior of frozen cemented tailings backfill at early ages

Abstract

Mining activities have become increasingly common in cold or permafrost regions. However, there is limited information regarding the behavior of cemented tailings backfill (CTB) cured under freezing conditions. This paper was aimed to assess the coupled effects of temperature and binder content on the mechanical and physical properties of frozen CTB. Thus, CTB mixtures with various binder contents (3, 5, and 7%) were tested at different curing times and temperatures (20, 0, −5, and −15 °C). The results indicated that, due to ice formation and hydration reaction inhibition at freezing temperatures, frozen CTB simultaneously presented higher strength and poorer structure, compared with CTB cured at normal temperatures (>0°C). The deformation behavior of frozen CTB showed ductile or slight strain-softening behavior that was dependent on the temperature and curing time. Moreover, binder content effects were greatly limited by freezing temperatures and the binder content had little effect on the properties of CTBs cured at −15 °C. However, when the temperature increased to −5°C, the higher binder content resulted in an increase in unfrozen water content, which led to lower strength. The present results demonstrated that the coupled effects of temperature and binder content on frozen CTBs were important factors for considering the design of cost-effective and safe CTB structures in cold regions.