The Research Of The Microscopic Pore And Filling Performance Of Coal Gangue Cementitious Paste

The status of coal accounting for more than 60%of China's energy structure will persist for a long time.Reducing the destruction of the natural environment by the mining industry and fully recovering limited resources is a major environmental task that China needs to complete.The mining model of high-strength paste with coal gangue pumping along the cement roadway filling and goaf filling to control surface subsidence is an important research direction for coal mines to control major accidents and subsidence environmental disasters in China and achieve safe production.(1)The raw material composition of the vermiculite cement material was analyzed to determine the physical and mechanical properties of the vermiculite cement material and the aggregate distribution curve of the aggregate.(2)On the basis of energy spectrum and XRD diffraction analysis of fly ash mineral components,the microstructure of fly ash and alkaline-excited fly ash with different grinding time at different curing ages was observed by scanning electron microscope,and the powder was determined by experiments.The activity index of coal ash explored the relationship among the composition,microstructure,mechanical activation and alkaline activated fly ash particle distribution,composition and activity of fly ash.(3)The pumpability and mechanical properties of the vermiculite binder were analyzed by the ratio test,and the slump,extension,exudation,delamination,and resistance of the cement material to the fly ash content and fine sagger ratio were obtained.The influence law of compressive strength obtained the best ratio of vermiculite cement material.(4)The microstructure of the vermiculite binder was analyzed by the mercury intrusion test.It was found that with the growth of the curing age,the proportion of non-hazardous and less harmful pores increased,the porosity of the vermiculite cement material gradually decreased,and the compression performance and compressive strength increased gradually.The increase of fly ash content will accelerate the hydration reaction,promote the progress and degree of the reaction,and improve the compression performance of the material.When the fineness rate is 40%,the compression performance of the vermiculite cement material is optimal.