Experimental study on performance of rubber-fly ash-based mine floor fissure grouting material

In response to the current challenges of high water pressure and easy conduction in kilometer deep wells, we propose the “hydrophobic pressure reduction, slurry reinforcement” mine water control technology, which requires slurry materials with “high strength, strong stability, easy flow, low cost” and other properties. “High strength” can be achieved by adding nano-reinforced materials. “Strong stability” can be achieved by preferentially selecting easy-to-consolidate and difficult-to-disperse raw materials and adjusting the mixing conditions. “Stable flow” can be achieved by adjusting the particle size of added raw materials and increasing the interfacial friction. “Low cost” can be achieved by using existing large-scale industrial and mining solid waste products that are in urgent need of treatment, supplemented by a small amount of additives. In view of the above problems, this paper aims at reinforcing the coal seam floor with slurry, and takes the large-scale utilization of industrial and mining wastes as the direction. By using waste tire rubber particles, fly ash and clay as the main materials, supplemented with a small amount of admixtures, the orthogonal test method is used to carry out experimental research on the basic performance of solid waste slurry filling materials. The effects of different rubber particle admixtures and admixtures were analyzed in the paper, and their effects on the flowability, mechanical properties, stability in mine water environment, impermeability and microstructural properties of the grouted stone body were derived. The research results show that when rubber particles are mixed with 20%, fly ash with 65%, clay with 15%, and nano-silica with 1% of solid powder, the flow of the grouted slurry is 293 mm, the 28 d compressive strength of the grouted stone body is 11.7 MPa, and the seepage pressure of the stone body is 0.8 MPa, and the obtained test results can meet the demand of field grouting reinforcement, which is useful for The obtained test results can meet the demand for on-site grouting reinforcement, which has scientific reference value for large-scale bottom slab fracture grouting reinforcement and also provides reference for large-scale utilization of solid waste products.