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    煤作泵送胶凝材料骨料粒度合理配比研究

    Study on reasonable aggregate size ratio of coal as pumping cementitious materials

    • 摘要: 为推动煤矿支护技术的绿色发展,降低泵送支护材料带来的二次污染,提出以原煤颗粒作为泵送胶凝材料的骨料。通过理论分析骨料级配最优配比,并利用试验得到了粗、中、细骨料对试样抗压强度、初始坍落度和1 h坍落度的作用规律。试验结果显示,抗压强度随30~20 mm粗骨料、20~5 mm中骨料占比的增加总体呈正相关,随5~0 mm细骨料占比的增加总体呈负相关。初始坍落度与1 h坍落度随30~20 mm粗骨料、5~0 mm细骨料占比提升均表现出先增大后减小的趋势,5~20 mm 中骨料对初始坍落度影响偏弱,但可显著提升 1 h 坍落度保持性能。结合相关性分析和权重评分法确定最优骨料级配为:30~20 mm∶20~5 mm∶5~0 mm = 20%∶25%∶55%。在现场应用中,按照30~20 mm粗骨料(占比20%~25%)、20~5 mm中骨料(占比25%~35%)及5~0 mm细骨料(占比45%~55%)进行配比的原煤骨料泵送胶凝支护材料,能够充分满足井下支护要求。

       

      Abstract: To advance the green development of coal mine support technology and reduce secondary pollution induced by pumped support materials, this paper proposes raw coal particles as aggregates for pumped cementitious materials. The optimal aggregate gradation ratio is determined via theoretical analysis, and the effects of coarse, medium and fine aggregates on the compressive strength, initial slump and 1 h slump of specimens are revealed through laboratory tests. The experimental results indicate that compressive strength is generally positively correlated with the increased mass proportion of 20~30 mm coarse aggregate and 5~20 mm medium aggregate, while it presents an overall negative correlation with the rising proportion of 0~5 mm fine aggregate. Both initial and 1-hour slumps generally show a trend of first increasing and then decreasing with the rising mass proportion of 20~30 mm coarse aggregates and 0~5 mm fine aggregates, while the 5~20 mm medium aggregates exert a weak influence on initial slump yet can significantly improve 1-hour slump retention performance. Combined with correlation analysis and weight scoring method, the optimal aggregate gradation is determined as follows: the mass ratio of 30~20 mm aggregate∶20~5 mm aggregate∶5~0 mm aggregate = 20%∶25%∶55%. In field application, coal aggregate pumped cementitious materials formulated with 30–20 mm coarse aggregates (20%~25% by mass), 20~5 mm medium aggregates (25%~35% by mass), and 5~0 mm fine aggregates (45%~55% by mass) can satisfy all performance requirements for underground mine roadway support.

       

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