Experimental study on the physical and mechanical properties of a cemented unclassified tailings backfill

Abstract

In order to study the physical and mechanical properties of cemented, unclassified tailings backfill, a series of unconfined compressive strength (UCS) tests have been performed on samples prepared in cubic and cylindrical shapes at 14, 28 and 56-day curing periods. Additionally, longitudinal wave velocities across all samples have been measured combined with ultrasonic pulse velocity (UPV), non-destructive testing technology. The influence of samples’ sizes, binder dosages and solids concentration the UCS and UPV were evaluated. The results indicate that samples with a diameter × height of 7.6 × 15.2 cm showed consistently higher UCS and UPV than those of 5 × 10 cm specimens at all solids contents and binder dosages, and the cylindrical specimens thus showed obvious size effects. Meanwhile, the samples with a side length of 7.07 cm (cube) showed higher UCS and lower UPV than the similar section size of 7.6 × 15.2 cm (cylinder) at the same binder dosage and solids content, and the end effects of cubical samples were more obvious. In addition, increasing the curing time led to the reduction of the ratio values for UCS and UPV of different size samples. Besides, with the increase of curing periods, a linear relation with a high correlation coefficient appears to exist between the UCS and UPV for the samples of specific sizes.