采空区充填新型浆液固化机理与影响因素研究

为了研究碱渣、粉煤灰和硅酸钠溶液制成的新型采空区充填注浆材料的固化机理,开展了扫描电镜和交互混合试验,并分析了原材料配比、碱渣过筛粒径和养护条件对抗压强度、凝结时间、结石率等工程指标的影响。结果表明:浆液体系早期固化是因碱渣中有效含钙成分与硅酸钠溶液反应生成水化硅酸钙凝胶(C-S-H),后期强度发展是因粉煤灰受碱激发形成了硅铝酸盐聚合物凝胶(N-A-S-H);原材料配比显著影响着浆液的各项工程性能指标;随着碱渣过筛粒径范围的减小,流动度、凝结时间和结石率都减小,而抗压强度增大,0.5 mm粒径是28 d强度增幅出现较大差异的临界点;高温高湿养护条件有利于浆液的固化进程。研究结果可供类似水泥注浆液材料制备参考。

New Grouting Slurry for Filling Goaf: Solidification Mechanism and Influential Factors

Soda residue, fly ash and sodium silicate solution have been synthesized as a new grouting material for filling goafs. In the present research, the solidification mechanism is explored by methods of scanning electron microscope and mutual blending. Moreover, the impacts of mix ratio, sieving particle size of soda residue, and curing condition on engineering indicators (compressive strength, setting time, and stone rate, among others) are examined by tests. Results demonstrate that the early solidification of slurry is determined by the calcium silicate hydrate gel (C-S-H) generated by calcium components of soda residue reacting with sodium silicate solution; and the later strength increment is determined by aluminosilicate polymer gel (N-A-S-H) formed by alkali-activated class F fly ash. The mix ratio of raw materials significantly affects the engineering properties of the slurry. With the shrinkage of sieving particle size of soda residue, the fluidity, setting time, and stone rate decrease, whereas compressive strength increases. Particle size 0.5 mm is the threshold for the increment of strength cured for 28 days. High temperature and humidity is favorable for the solidification process of slurry.