Abstract:At present, it is commonly believed when the cement content is fixed, the strength of cemented backfill is only determined by the concentration of tailings slurry. But this opinion does not take the influences of slurry bleeding on cemented backfill into account. In this study, by using a designed bleeding testing mould, the bleeding features and the influences on cemented backfill of tailings slurries with different cement content and tailing types have been studied. The experimental results showed that: ①Even adding a small amount of cement can significantly decrease the volume of slurry bleeding, therefore by using backfill with small cement content can achieve the goal of bleeding control. ②The slurry bleeding can dramatically decrease the concentration differences between tailings slurries with different original concentrations. While after bleeding, there are still some obvious volumetric moister content difference between different cemented backfills, indicating their porosities are different. ③The closer the particle size of the filling aggregate is, the smaller of the differences between slurry concentration and volumetric moisture content of the backfill after bleeding. Therefore, there are some disadvantages in the evaluation of strength of cemented backfill only by using the filling concentration as the standard.

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