Abstract: In order to lower high cost in mine backfilling, the effect of calcium carbide slag on the properties of backfilling cementitious material was studied by tests of preparing backfilling cementitious material with industrial waste, such as steel slag and mine slag, as the main component. The mineral composition and morphology of backfilling cementitious material were analyzed by XRD and SEM. The results showed with the addition of 15% calcium carbide slag, the 3 d and 28 d compressive strength of backfilling cementitous materials were 16.1 MPa and 38.6 MPa, and improved by 34.7% and 26.3% respectively comparing that without calcium carbide slag mixed. With the addition of 25% mine slag instead of steel slag, its 3 d and 28 d compressive strength reached 26.4 MPa and 48.3 MPa, and increased by 63.9 % and 28.5% respectively comparing that without the mine slag samples mixed. Moreover, the setting time was reduced.

Key words: Calcium carbide slag, Steel slag, Backfilling cementitious material, Properties