碱渣改良矸石胶结充填材料力学性能试验研究北大核心

基于固废碱渣排放量大、处理成本高和污染环境的背景,探讨利用碱渣改良矸石胶结充填材料力学性能的可行性;通过测试碱渣基本物理力学特性,研究碱渣掺量和养护龄期对胶结充填材料力学性能的影响规律及其强度机理。结果表明:随着碱渣掺量在0%~12%范围内逐渐增大,充填体早期强度、中期强度和后期强度均呈现出先增强后降低规律;碱渣胶结充填材料的最佳配合比为碱渣∶粉煤灰∶石灰∶水泥∶矸石∶旧集料=6%∶34%∶10%∶2.5%∶24%∶23.5%,材料早期强度和后期强度增幅高达449%和187%;碱渣胶结充填材料料浆体系中C-S-H胶凝与N-A-S-H胶凝共存,N-A-S-H胶结性能更强,减少了孔隙的连通性,适量的碱渣掺量能够有效提高材料强度;碱渣制备胶结充填材料能够实现节能减排,其技术、经济与社会效益显著,具备良好的工程应用价值。

Experimental study on mechanical properties of gangue cemented filling material improved by alkali residue

Based on the background of large amount of solid waste alkali slag, high treatment cost and environmental pollution, the feasibility of using alkali slag to improve mechanical properties of gangue cemented backfill material was discussed. In this paper,the basic physical and mechanical properties of alkali slag are tested, and the influence law and strength mechanism of alkali slag content and curing age on mechanical properties of cemented filling materials are studied. The results show that: with the increase of alkali slag content in the range of 0%-12%, the strength of the backfill in the early stage, the middle stage and the later stage show the law of first strengthening and then decreasing;the optimum mix ratio of alkali slag cemented backfill material is alkali slag∶ fly ash∶ lime∶ cement∶ gangue∶ used aggregate=6%∶34%∶10%∶2.5%∶24%∶23.5%, and the early strength and late strength of the material increase up to 449% and 187%;C-S-H cementation coexists with N-A-S-H cementation in the slurry system of alkali slag cemented backfill material, and N-A-S-H cementation has stronger cementation performance, which reduces the connectivity of pores. An appropriate amount of alkali slag can effectively improve the strength of the material. The cemented filling material prepared by alkali slag can realize energy saving and emission reduction, and its technical, economic and social benefits are remarkable, and it has good engineering application value.