掺粉煤灰的混合充填骨料配比优化实验

针对某矿山采用混合粗骨料存在充填料浆分层离析的问题,通过添加粉煤灰细骨料来优化骨料级配.首先对充填材料进行物化分析,并在此基础上开展不同粉煤灰掺量的混合骨料粒径级配分析,然后进行掺粉煤灰混合骨料充填体强度实验,实验结果表明:充填体强度随着料浆浓度与粉煤灰掺量的增加而提高,强度改善明显;掺入适量粉煤灰细骨料,能有效改善粒径级配,提高充填体强度.最后以单位充填成本为优化目标,以各龄期强度为约束条件建立优化模型对混合骨料充填配比进行优化,得出满足充填强度要求的最低成本方案,即粉煤灰掺量26％、胶凝材料添加量为286 kg/m3,料浆浓度为81.36％时充填材料成本最低,并以此进行验证实验,得到3d强度为1.56 MPa,7 d强度为2.86 MPa,28 d强度为6.9 MPa,塌落度25.6 cm,分层度3.1 cm,泌水率为5.7％,均满足矿山要求,此时充填成本为124元/m3,较原来的145元/m3降低了 14％.

Optimum experiment of aggregate proportion for mixed filling with fly ash

In view of the problem of stratification and segregation of filling slurry in a mine using mixed coarse aggregate, the aggregate gradation is optimized by adding fly ash fine aggregate.Firstly, the physical and chemical analysis of filling material is carried out, and on this basis, the particle size gradation analysis of mixed aggregate with different fly ash content is carried out. Then, the strength test of fly ash mixed aggregate filling body is carried out. The test results show that the strength of filling body increases with the increase of slurry concentration and fly ash content, and the strength improves obviously. Adding appropriate fly ash fine aggregate can effectively improve the particle size. Diameter gradation can improve the strength of filling body. Finally, with the unit filling cost as the optimization objective and the strength of each age as the constraint condition, an optimization model was established to optimize the filling ratio of mixed aggregate. The lowest cost scheme to meet the filling strength requirement was obtained, that is, 26% fly ash, 286 kg/m3cementitious material and 81.36% slurry concentration. 7dstrength is 1.56 MPa, 7d strength is 2.86 MPa and 28d strength is 6.9 MPa,the slump is 25.6cm, the stratification is 3.1cm, and the bleeding rate is 5.7%, which all meet the requirements of the mine. At this time, filling cost is 124 yuan/m3, which is 14% lower than the original 145 yuan/m3.