全尾砂-粗骨料膏体早期抗压强度影响规律及固化机理

来源期刊:中南大学学报(自然科学版)2020年第2期

论文作者:尹升华 刘家明 邵亚建 张海胜 ARMELLE Belibi 寇永渊

文章页码:478 - 489

关键词:粗骨料;早期抗压强度;膏体;多元非线性回归;固结机理

Key words:coarse aggregate; early compressive strength; paste; multiple nonlinear regression; consolidation mechanism

摘    要:以某矿尾砂、废石、棒磨砂为实验材料,采用正交设计实验方法,研究膏体质量分数、水泥掺量、尾骨比(全尾砂、废石和棒磨砂质量比)、泵送剂掺量对充填体早期抗压强度的影响规律。对实验数据进行三维曲面可视化分析和多元非线性回归分析,最后根据实验结果对膏体固结性能的机理进行分析。研究结果表明:水泥掺量和质量分数是早期抗压强度的主要影响因素,m(全尾砂):m(废石):m(棒磨砂)以及泵送剂掺量存在最优值,最优值范围分别为5.0:2.5:2.5~4:3:3和1.5%~2.0%。多元非线性二次多项式回归拟合效果最佳,根据所选模型和主观权重T可知,所得目标函数f存在最大值和最小值,最大值为8.97 MPa,最小值为2.87 MPa,均满足7 d强度要求(R7≥2.5 MPa);粗骨料的掺入不仅能进一步提高早期抗压强度,而且粗骨料中的活性物质能与Ca(OH)2发生反应,起到部分胶凝效果。

Abstract: Taking a mine tailings and waste rock and rod-mill sand as the experimental materials, the orthogonal design method was adopted to study the influencing rules of the paste mass fraction, cement content, tailing-aggregate ratio (mass ratio of full tailings to waste rock and rod-mill sand) and the addition of pumping agent on the early compressive strength. Three-dimensional curved surface visualization analysis and multivariate nonlinear regression analysis were carried out on the experimental data. Finally, the mechanism of paste consolidation performance was analyzed based on the experimental results. The results show that cement content and paste mass fraction are the main influencing factors of early compressive strength. There is an optimal value of m(full tailings):m(waste rock):m(rod-mill sand) and pumping agent content and the optimal values range from 5.0:2.5:2.5 to 4:3:3 and from 1.5% to 2.0%, respectively. The nonlinear regression fitting of multiple nonlinear quadratic polynomials has the best effect. According to the selected model plus the subjective weight T, the obtained objective function f has the maximum and minimum values, that is 8.97 and 2.87 MPa, both of which meet the 7 day strength requirement (R7≥2.5 MPa). The addition of coarse aggregate can not only further improve the early compressive strength, but also the active substances in coarse aggregate can react with Ca(OH)2 and play a part in the cementing effect.

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