Feasibility of natural bamboo branches aggregate applied to the thermal insulation layer of rock walls in roadways

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The high-temperature heat damage is mainly caused by heat dissipation of surrounding rock in deep mining of mine, so spraying thermal insulation layer (TIL) on mine roadway can be used to actively heat insulation. As a kind of green material, bamboo branches have excellent thermal insulation and mechanical properties. In this paper, gravel and ceramsite were used as aggregate, bamboo branches and glass hollow bead were used as main thermal insulation materials, and the effects of different content, diameter, and length of bamboo branches on mechanical properties, thermal insulation properties, and microstructure were studied through orthogonal experiments. A group of specimens with the best comprehensive performance was selected through the analysis of the efficiency coefficient, and the optimal ratio was determined. This ratio ensures the perfect balance between insulation and strength for TIL, which is essential for the preparation of TIL. At the same time, the numerical simulation software Fluent was used to establish the roadway model, and the cooling effect of the TIL on the airflow temperature in the roadway under different working conditions was studied based on the parameters of the selected specimens. These parameters are based on the actual characteristics of the specimen, and their accuracy ensures the reliability and validity of the research results. The results show that under the optimal mixing ratio, the thermal conductivity (TC) of the specimen is 0.224 W/(m·K), the thermal insulation performance of the prepared coating is increased by 25∼65 %, and the mechanical strength is also improved. The optimal mix ratio obtained in this study can be applied to the field of mine thermal damage control, and the feasibility of natural bamboo branches for preparing roadway thermal insulation material is demonstrated. Bamboo branches grow rapidly, and their use as thermal insulation materials will not only not cause a burden on the environment, but help to promote ecological recycling and achieve sustainable use of resources.