Performance Test and Thermal Insulation Effect Analysis of Basalt-Fiber Concrete

• Published in: Materials Vol. 15; no. 22; p. 8236
• Main Authors: Zhang, Xiao, Zhang, Shuo, Xin, Song
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 21.11.2022; MDPI
• Subjects: Analysis; Basalt; basalt fiber; Cement; Clumps; Coal industry; Coal mines; Coal mining; Compressive strength; Cost benefit analysis; Costs; Design specifications; Economic analysis; Electric properties; Fibers; Heat conductivity; Heat transfer; high geothermal roadway; impermeability; Insulation; Mechanical properties; Mineral industry; Mines; Mining industry; Mixtures; Numerical analysis; Performance tests; Permeability; Roads; Roads & highways; SEM images; Simulation; Simulation methods; Tensile strength; Thermal conductivity; Thermal insulation; Thermal resistance; Thermodynamic properties; Underground mines; Underground roadways; China; compressive strength; basalt fiber; SEM images; thermal insulation; cost-benefit analysis; impermeability; high geothermal roadway; numerical simulation
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma15228236

This paper examines the feasibility of applying inorganic thermal-insulating concrete in high geothermal roadways in underground coal mines. This innovative material is based on a mixture of ceramsite, glazed hollow beads, cement, and natural sand, enhanced with varying degrees of basalt fibers. Fibers were used as a partial substitute in the mixture, in the following volumes: 0% (reference specimen), 5%, 10%, 15%, and 20%. Their compressive strength, permeability resistance, and thermal conductivity were studied. A high content of fibers tends to entangle into clumps during mixing, resulting in a significant reduction in the mechanical properties of compressive strength. The appropriate amount of fiber content can improve impermeability, and the permeability height of 5% fiber concrete was reduced by 22.5%. Experiments on thermal behavior showed that an increase of basalt fibers leads to a significant reduction in thermal conductivity. For concrete containing 20% fiber, the thermal conductivity for the reference specimen (0%) in the wet state was reduced from 0.385 W/(m∙°C) to 0.098 W/(m∙°C). There was a slight increase in thermal conductivity when the temperature increased from 30 °C to 60 °C. Despite the reduced mechanical strength, the resulting concrete is well-suited for use in the insulation of underground roadways, as numerical simulations showed that insulating concrete with optimal fiber content (15%) can reduce the average temperature of the wind flow in a high ground temperature roadway of 100 m in length in a mine by 0.3 °C. The final cost-benefit analysis showed that insulating concrete has more economic benefits and broad development prospects when applied to high geothermal roadway cooling projects.