Experimental study on acoustic emission characteristics of cemented rock-tailings backfill

Cemented tailings backfill is an important development tendency of mine filling. Aiming at the cemented rocktailings backfill material, the experimental tests on the acoustic emission characteristic of the backfill body under uniaxial compression was carried out, in which different cement-sand ratios (1:4, 1:6, 1:8, respectively) and waste rock contents (0%, 10%, 20%, 30%, 40%, respectively) were adopted. Through characteristics analysis of AE ringing count, cumulative hits and r value, the strength and deformation characteristics of the backfill body were obtained, and the influence mechanism of cement-sand ratio and waste rock content on the mechanical properties of the backfill body was revealed. The results indicated that as the waste rock content increased, the primary pores of the backfill body increased, the elasticity of backfill reduced, the plasticity of backfill increased, the uniaxial compression strength of the backfill body firstly increased and then decreased, the residual strength in the post-failure stage of backfill increased. Through analysis of microstructure by SEM and XRD tests, it was found that the most hydration products of the backfill body were C-S-H, followed by AFt and Ca (OH) 2, while the C-S-H was the main source of the cement-based materials strength.