干旱区工业废渣粉煤灰回填材料拌合物的流动性能研究

Research on the flow ability of mixture of flowable backfill materials using industrial waste fly ash in arid zone

针对干旱区存在大量的粉煤类废弃物及回填工程中作业面受限或结构物死角存在压实不到位的工程问题,提出以粉煤灰为主要成分、以及部分砂、水泥的流动化回填材料,分析拌合物流动性能受材料掺量、时间影响的变化规律,建议采用坍落扩展度作为流动性能评价指标,水泥掺量对流动性能影响甚微,坍落扩展度与水固比成线性关系;同一种集料,不同粉煤灰掺量拌合物达到相同的流动性能,水固比呈先降后升的变化趋势;拌合物坍落扩展度在前60min内降低显著,随时间变化,坍落扩展度趋于一致,拌合物中集料颗粒越小,保持流动性的能力越强。

Aimed at a lot of fly ash in arid areas and engineering problems in engineering practice that it is hard to effectively backfill when work surface is limited or there are dead angles in structures. We designed a kind of backfilling mixtures whose main ingredient was fly ash, sand and cement. Variations of flow properties of mixture that were influenced by material content and time were analyzed. Slump flow was recommended to evaluate the flow properties of mixture. Mixing amount of cement had minimal impact on the flow properties. Slump flow had a linear relationship with water. Aggregate had a significant influence on the flow properties of mixture. For the same aggregate with different mixing amount of fly ash when it reached the same flow properties, the required wa- ter - solid ratio rose after the first fall. Slump flow of the mixture reduced significantly within the first 60minutes, the drop of slump flow turned slow and converged as the time changing. The mixture whose aggregate was smaller had a stronger ability to maintain fluidity.