固体充填胶凝材料试验研究与应用

Experimental research and application of solid filling cementitious materials

针对目前“三下”采煤充填成本较高和充填效率低下等问题,以矿粉这种低成本水硬性胶材为主,辅以少量石膏和水泥熟料,得到了适用于矿山高效固体充填的早凝、低成本的胶凝材料。通过对矸石粒径级配和胶凝材料固化机理进行了分析,设计正交试验确定出胶凝材料最优配比,即:当石膏5%、水泥熟料25%、矿粉70%时,可实现短时间脱模,表明在该掺量下胶凝材料的水化反应程度最好,其中矿粉中的活性成分能够在早期反应生成水硬性钙矾石(AFt),促进充填体强度的形成。养护后充填体的7d、28d强度可达到3.48MPa、5.11MPa,略低于425^(#)硫铝酸盐双快水泥的7d和28d成型强度,但在成本上具备明显优势。结合工业应用,对实际充填效果、液压支架工作阻力和地表沉陷观测数据进行分析,表明该胶凝材料在提高充填效率、加强顶板管理等方面发挥着积极作用。

Aiming at the high filling cost and low filling efficiency of coal mining under buildings,water bodies and railways,we mainly use mineral powder,a low-cost hydraulic cementitious material,supplemented by a small amount of gypsum and silicate clinker,an early-setting,to prepare a low-cost cementitious material for high-efficiency solid backfilling.We also analyzed the size grading of gangue and the curing mechanism of the cementitious material,the optimal ratio of cementitious materials is obtained orthogonal experiments,when gypsum content is 5%,cement clinker content is 25%,and mineral powder content is 70%,the filling body can be demoulded in a short time,it shows that the degree of hydration reaction of the cementitious material is the best at this content,the active ingredients of the mineral powder can react in the early stage to form hydraulic ettringite(AFt),which promotes the formation of the strength of the filling body,the 7 d and 28 d strength of the filling body can reach 3.48 MPa,5.11 MPa after curing,it is slightly lower than the 7 d and 28 d forming strength of 425^(#)sulphoaluminate double fast cement,but it has obvious advantages in cost.Combining with industrial applications,we analyze the actual filling effect,the working resistance of the hydraulic support and the observation data of ground subsidence,the result shows that the cementitious material plays a positive role in improving filling efficiency and strengthening roof management.