Effect of phyllosilicates presence on hardening process in cemented paste backfills

The decline in strength of cemented paste backfill (CPB) presents a recurrent challenge in underground backfilling operations. The heightened presence of phyllosilicates in CPB is recognized as a key factor contributing to its strength degradation. While some studies in civil engineering have delved into similar phenomena, noting a decrease in concrete strength with rising mica content, there is a conspicuous gap in research addressing this specific phenomenon within cemented paste backfill. This study systematically investigates the mechanical and mineralogical responses of CPB influenced by phyllosilicates, specifically muscovite, addressing both quantitative and qualitative dimensions. The primary objective is to scrutinize the influence of varying muscovite contents on the hydration characteristics of the binding agent within CPB. The experimental program is meticulously designed to unveil considerable changes in CPB’s mineralogical and mechanical properties across diverse muscovite contents (0%, 3%, 12%, and 18%) at long-term curing, 91 days. This investigation employs one binder type, general use Portland cement (type GU) at 7% content. The findings from this study provide fresh perspectives on how phyllosilicates, particularly muscovite, impact the mechanical and mineralogical properties of CPB during both mixing and hardening phases. These insights contribute valuable knowledge for refining new CPB recipes by thoughtfully considering the phyllosilicates content in mine tailings.