Study on the Properties of New Sprayed Gas-Sealing Material Modified by Cement-Fly Ash in Mine
Spontaneous combustion of coal in goaf is one of the major disasters faced in coal mining.It not only wastes coal resources,causes significant economic losses,but also leads to accidents and casualties.To minimize the leakage of oxygen into the goaf,gas-sealing materials are frequently sprayed on the coal wall adjacent to the goaf,aiming to seal the coal wall cracks generated by mining activities.A new type of sprayed gas-sealing material was prepared by modifying cement-fly ash as matrix materials with hydroxypropyl methyl cellulose(HPMC)and tributyl phosphate(TBP).The effects of different contents of HPMC and TBP on the coating properties were derived from the water precipitation rate tests,water retention rate tests,mechanical strength tests and contact angle tests of cement-based material and coal interface.The tests results show that the best comprehensive performance of the material can be achieved when the water-solid ratio is 0.5,the content of fly ash is 20％,the content of HPMC is 0.2％and the content of TBP is 0.08％.When the water precipitation rate of the slurry is lower than 5％,the 7 d compressive strength and flexural strength of the material can reach 16.70 MPa and 5.02 MPa,respectively,which are increased by 6.58％and 2.87％compared with the pure cement-fly ash material.After modification,the initial contact angle between the slurry and the coal is reduced by 21.83°.Finally,the effect of admixtures on the hydration mechanism and microstructure of cement was derived from X-ray diffraction analysis,Fourier infrared spectrum analysis and scanning electron microscope analysis.
New sprayed gas-sealing materialSpontaneous combustion in goafCement-fly ash based materialHydroxypropyl methyl celluloseTributyl phosphate
万方数据
维普
