Investigating the properties of sprayed insulating cementitious materials with corn cobs

Abstract

As the mining depth increases, the underground space will face more serious thermal hazards. By using corn cobs, an agricultural waste, to prepare cementitious insulation materials, active insulation layers are constructed by injecting insulation materials into underground spaces using cementitious material spraying techniques. This article designed the ratios of corn cob sprayed cementitious materials and analyzed the changes in the properties of the materials obtained by adding 0–25% of corn cobs. The results of the study showed that the addition of different proportions of corn cobs improved the thermal insulation properties of the material by 6.9%-75.5% as compared to the ordinary mortar material. The mechanical properties became 25.9%-113.6% of the original. When the corn cob is wetted for more than 10 min, the fluidity of the material is sufficient to reach the minimum standard for spraying operations. Considering the comprehensive performance of the material, it is concluded that the wetting time of 30 min, the addition of corn cob 20%, the corn cob particle size of 200 mesh, and the amount of sand doping of 40% are the optimal ratios of the studied corn cob spraying cementitious materials. The study of corn cob lightweight thermal insulation spray cementitious material is of great significance for controlling the ambient temperature in deep underground space, promoting cleaner production and improving the use of environmental resources.

Keywords

• Corn cobs
• Sprayed cementitious materials
• Thermal insulation performance
• Mechanical properties
• Orthogonal experiment