Research on the microstructure and physicochemical properties of coal gangue-based filling material used for grouting in overlying strata
The overlying strata in coal mining areas have a significant impact on surface subsidence and mining safety.Grouting filling is the main method to solve this problem,where the filling material determines the cost and actual effect of separation layer filling.In order to solve the problem of grouting and filling in the separated strata of overburden in Shen-dong mining area,this paper systematically studies the physical and chemical composition and grouting properties of coal gangue raw materials in Shen-dong mining area.The performance of coal gangue-based anti-well material under various water to cement ratio and different composition grades were investigated.By preparing three experimental materials with different water to cement ratios of pure gangue,the gangue added with fly ash,and gangue blended with fly ash and Portland cement,the key properties of curing behaviors,compressive strength,fluidity,and the bleeding rate of these filling materials were analyzed.And the influence mechanism of the addition of fly ash and cement on the performance of coal gangue-based filling materials was investigated.Results indicate that the compressive strength of the three filling materials decreases with the increase of water to cement ratio.The early strength(3 d,7 d)and late strength(28 d)of the pure gangue and the gangue mixed with fly ash are all lower under the same water to cement ratio,which are below 1 MPa.After adding cement into the filling materials,the early strength(3 d,7 d)of this material(gangue+fly ash+cement)significantly increases,and the later strength(28 days)are greatly enhanced.As a cementitious material,cement plays an important role in ball-lubricated and cross-linking between multi-angular coal gangue aggregates,reducing mechanical engagement between aggregates and improving the fluidity of mortars.
gangueseparation layer groutingfilling materialphysical and chemical propertiesmechanical
万方数据
维普
