骨料颗粒级配对充填用煤矸石混凝土力学性能的影响

Influence of Aggregate Particle Gradation on Mechanical Properties of Coal Gangue Concrete for Filling

为解决煤矿采空区充填成本高、煤矸石和粉煤灰堆存占用大量土地及污染环境等问题,在满足工程实际需求的前提下,研究制备了采空区煤矸石基充填材料。以F类粉煤灰、黏土岩类煤矸石和32.5号水泥为原料,通过正交试验对比优化出煤矸石∶粉煤灰∶水泥=5∶1∶2(质量比),固体质量浓度为80%是采空区煤矸石基充填材料的优势配比。A.N.Tabol公式系数n=0.4时,煤矸石的骨料颗粒级配最佳,骨料空隙率最小,为29.3%,表观密度和紧密堆积密度最大,分别为2 336.40 kg/m^(3)、1 582.90 kg/m^(3),对应混凝土试块的强度最高,材料在7 d和28 d的单轴抗压强度为3.22 MPa和7.01 MPa,均满足采空区的充填强度要求。

In order to solve problems of high cost of the coal goaf filling, high occupation of coal gangue and fly ash, and environmental pollution, in the premise of meeting the practical engineering requirements, the coal gangue-based filling materials for goaf are studied and prepared. Using F-type fly ash,clay coal gangue and No.32.5 cement as raw materials, the orthogonal test is conducted to obtain the optimal ratio of coal gangue for goaf with the mass ratio of coal gangue ∶fly ash ∶cement =5 ∶1 ∶2 and solid mass concentration of 80%. When the n(formulation coefficient of A. N. Tabol) is 0.4, the coal gangue has the optimal aggregate particle gradation, lowest aggregate void ratio which is 29.3%, largest apparent density of2 336.40 kg/m^(3), largest compact packing density of 1 582.90 kg/m^(3), and highest strength of concrete test s pecimen. The uniaxial compressive strength of the material at day 7 and day 28 are 3.22 MPa and 7.01 MPa respectively, both of which meet the filling strength requirements of the goaf.