Shear strength between cemented paste backfill and natural rock surface replicas

摘要

After placement underground, the physical-chemical and mechanical properties of cemented paste backfill (CPB) will evolve over time due to self-weight consolidation and binder hydration. This paper deals with an experimental investigation into the shear strength behaviour of the CPB-rock interfaces using a direct shear machine. Numerous shear tests were conducted. The rock interfaces were made from two natural rock surfaces (schist and granite) in SikaGrout? mortar replicas. Both frictional shear and shear bond strengths were determined. The results show that the shear strength at the schist interface (rougher) is higher than the one at the granite interface. The shear bond strength or cohesion and the interfacial angle of friction depend on the CPB curing time and the applied normal stress.