An Experimental Study on Shear Strength of Cemented Paste Backfill Materials

Change in the mechanical parameters of cohesion and internal friction angle with variations in cement content and curing time of cemented paste backfill (CPB) materials was investigated carrying out a series of experimental study. In this scope, shear strength and uniaxial compressive strength (UCS) tests were performed to find out the failure properties of CPB samples. According to the results obtained from this study, a new factor is suggested to use in the Mohr-Coulomb failure criterion to better fit the envelope for CPB materials. As an important issue from this study, strength values of curing CPB specimens were found to dominantly increase because of the improvement in cohesion values instead of internal friction angle. With an increase in cement content, strength values were measured to increase because of the improvement in both internal friction angle and cohesion parameters. Additionally, start of decrease in strength values due to the sulphate attack was found be postponded as another advantage of the increase in cement content