Experimental study on adhesive and sealing performance of fire protection spray materials

Sprayed fireproofing materials in underground coal mine roadways are limited due to their poor adhesion, easy-to-crack, easy-to-fall off and poor sealing effect. This study therefore develops a fireproofing spraying material with fly ash as aggregate, ordinary silicate cement, sulphur-aluminate cement and gypsum as base material, and re-dispersible latex powder(VAE)as additive. Specifically, we conducted the uniaxial compressive strength test and used coal rock multiphase multi-field triaxial dynamic seepage experimental system, and scanning electron microscopy to study the effects of dispersible latex powder on the adhesive, cementation, mechanical, and blocking properties of the spray material. The results show that adding dispersible latex powder could promote the formation of filamentary bonding bridges in the hydration product, and realize the riveting and bridging of the binder bridges with the hydration products to form a dense network structure. This improves the cracking resistance of the spray material and enhances the material's adhesion, sealing and cementing properties when combined with coal. Adding 1 % VAE spraying material can fully encapsulate the coal body, forming a dense coating on the surface of the coal body, effectively isolating the air from contact with the coal body, thus preventing spontaneous combustion of coal. The proposed materials are useful in preventing spontaneous combustion of coal at the top of the roadway.