Study on Characteristics of Composite Fire Extinguishing Spray Sealing Material

In order to solve the problem of spontaneous combustion of coal seam caused by air leakage in goaf, a new type of composite fire extinguishing and spraying sealing material based on pneumatic spraying technology and inorganic material is developed in this paper. The research shows that when the water cement ratio is 0.7:1 and the compound admixture is 2% of the composite spraying sealing material, the initial setting time is 15.8 min；at 5 min, the viscosity of the spray slurry is 14.745 1 Pa·s；and the material performance is excellent. The infrared spectrum analysis shows that the composite additive helps to improve the material properties of inorganic materials. The material has high strength at early stage and stable strength at later stage, compressive softening coefficient （0.825） of 28 days is good. Cementing experiments show that the bond between the material and the coal is good. After field application, the leakage rate of 100 meters of spraying roadway was reduced from 6.5 m³/min to 0.7 m³/min.