Study On New Coal Gangue Paste Roadway Supporting Filling Material

Coal gangue, a kind of industrial residues, is generated in the process of coal mining.With the quick development of coal industry, the amount of coal gangue increase quickly. Inaddition it could take up a lot of land and pollute the environment. Undenr coal mining, a lotof mined-out area due to underground mining, leading to the surface subsidence.Paste filling mining was processed into toothpaste paste with coal gangue, fly ash,industrial slag and city solid waste. And pump to underground, forming support system mainwith paste filling body. It could effective control surface subsidence. Waste reclamation andreducing the filling cost will not only be realized, but also the pollution of coal gangue andsurface subsidence will be solved.1) The effect of calcium carbide slag dosage on the activity of coal gangue wasresearched in the coal gangue activation study. The activation of coal gangue was improvedby add calcium calcining. SEM and XRD were used to analysis the composition andorphology of coal gangue. CA and CS of low hydration activity was produced with calciumcarbide slag content of15%; C₃A and C₂S of hydration activity was produced with calciumcarbide content of25%-35%. And the f-CaO content and calcium carbide slag consumptionincreased along with increase calcium carbide slag content.The effect of coal gangue activity motivated was evaluated with coal gangue gelledmaterial glue sand strength. The compressive strength and bending strength of sampleincreased and then decreased with increase calcium carbide slag content, the optimal amountranges from25%to35%of calcium carbide slag, the optimal compressive strength andbending strength of sample with calcium carbide slag content of35%,3d,7d,28dcompressive strength and bending strength reached15.5MPa,22.3MPa,33.8MPa and2.6MPa,3.8MPa,6.7MPa.2) In the coal gangue cementitious material preparation, the effect of coal gangueactivation material, gypsum, exciting agent and compound activator on the performance ofcoal gangue cementitious material was researched, and hydration mechanism of cementitiousmaterial was studied. The effect of coal gangue activation material on the performance of coal ganguecementitious material was researched. The mechanic strength of coal gangue cementitiousmaterial reduced with increase coal gangue activation material. The3d,7d,28dcompressive strength and bending strength reached15.2MPa,22.8MPa,35.5MPa and2.4MPa,3.7MPa,6.8MPa with coal gangue activation material content of60%.The effect of gypsum on the performance of coal gangue cementitious material wasresearched The mechanic strength of coal gangue cementitious material increased withincrease gypsum. The3d,7d,28d compressive strength and bending strength reached15.7MPa,24.4MPa,37.8MPa and2.3MPa,3.6MPa,6.7MPa with gypsum content of4%.The effect of exciting agent and compound activator on the performance of coal ganguecementitious material was researched The mechanic strength of coal gangue cementitiousmaterial increased with increase activator. The optimal amount of windshield wipers, alkalineand sulfates was4%,1%and1%. And the best ratio of complex activator was windshieldwipers: alkaline: sulfates=5:1:1; the optimal amount of complex activator was5%, the3d,7d and28d compressive strength of coal gangue cementitious material reached27.5MPa,35.4MPa and55.4MPa with complex activator content of5%.3) In the coal gangue paste filling material preparation, the effect of cementitiousmaterial, aggregate ratio, slurry concentration and conservation periods on the strength andfluidity was researched.The effect of cementitious material on the strength and fluidity was researched The pasteflow and backfill strength with coal gangue cementitious material as cementing agent is muchbetter than cement in same concentration and aggregate ratio situation. Compare with cement,the paste collapsbillity of coal gangue cementitious material as cementing agent increased26.3%, the3d,7d,28d and90d compressive strength of the backfill increased14.7%,12.2%,13.2%and17.5%, with paste concentration for80%and aggregate ratio for coalgangue and fly ash.The effect of aggregate ratio on the strength and fluidity was researched The paste flowand backfill strength was improved with add right amount fly ash. The paste collapsbillityincreased41.2%, the3d,7d,28d and90d compressive strength of the backfill increased25.8%,16.9%,16.7%and19.9%, with fly ash partially replace coal gangue as aggregate. The effect of slurry concentration on the strength and Fluidity was researched. Thebackfill compressive strength increased and the paste flow reduced with concentrationincreased.The effect of conservation periods on the strength and fluidity was researched. Thebackfill strength increased with coal gangue cementitious material as cementing agent withconservation periods increased.