Experimental study on early-strength of cemented paste backfill

The purpose of this study is improving the strength of the cemented paste backfill. Also the effect of blast furnace slag (BFS) was investigated on short - term mechanical properties of CPB. In this study, CPB samples were prepared by 9% portland cement and also 25%, 50% and 75% of the cement were replaced with BFS. The paste materials prepared according to the value of 180 mm slump were cast into cylinder molds. The uniaxial compressive strength (UCS) and Ultrasonic P-Wave Velocities tests were performed. The maximum values of UCS 0.80, 1.70 and 3.03 MPa respectively at 3, 7 and 14 curing period were obtained from 25 wt% BFS added samples. 25%wt. BFS showed a strength of 1.79 times in the 7 days cure period and 2 times in the 14 day cure period according to the reference cemented samples. On the contrary, substitution of 50 and 75 wt.% BFS were reduced strength of CPB samples. Ultrasonic pulse velocity of cemented paste backfill showed similar trend with UCS. But, substitution of 25, 50 and 75 wt.% BFS were below the values of reference samples. The maximum values of UCS are 25% additive BFS. This situation directly affects the cost of CPB due to reduces the cement ratio.