Experimental Study on the Basic Properties of a Green New Coal Mine Grouting Reinforcement Material

Waste tires are internationally recognized as hazardous waste. Many waste tires storing in the open air for a long time will not only waste the land resources but also pollute the environment after the incineration. Meanwhile, the cumulative accumulation of fly ash in China has also been one of the largest sources of solid waste in coal mines. Under the action of high winds, the accumulated fly ash forms flying dust, which pollutes the environment and endangers human health. Herein, a new type of grouting material for floor reinforcement was developed based on solid waste products using the waste tire rubber particles and fly ash. Using this new material, disaster accidents such as flooding and casualties caused by the inrush of the floor-confined water due to floor fractures, activation, and expansion in the mining process can be greatly reduced, thereby ensuring the safety of coal mine production. The grout body was prepared using a large amount of fly ash, waste tire rubber particles and clay, and mixing additives. The ratio optimization test, uniaxial compressive strength test, permeability characteristic test, stability test, and microanalysis of mine water environment were performed. From the test results, the macrophysical and chemical properties including optimal mix ratio, compressive strength, permeability coefficient, and stability of mine water environment were obtained. The microstructural properties of the grouts were analyzed using scanning electron microscopy microanalysis methods. Considering the situation of the coal floor and attempting to use as many solid waste products as possible, the optimized proportion that can meet the requirements of low cost, high bonds, and dense filling is as follows: 20% of rubber particles, 65% of fly ash, 15% of clay, and 1% of nanosilica. Furthermore, this study can provide scientific reference for large-scale floor grouting reinforcement and large-scale utilization of solid waste products.