Abstract To investigate the changes in mechanical properties of shotcrete in high-temperature hydrothermal envi? ronments and related improvement measures, tests were conducted on plain shotcrete, shotcrete with hooked-end steel fibers, and wavy steel fibers under three conditions: 20°C (room temperature water), 60°C, and 80°C hot water.The study focused on the splitting tensile strength and uniaxial compressive strength of these shotcrete mixtures.The results show that hot water accelerates the early hydration reaction of concrete and improves early mechanical properties. However, long-term exposure leads to the decomposition and reorganization of C-S-H gel, reduced densification of hydration products, and deterioration of interface performance, which causes a decrease in strength over time. Compared to room temperature (20°C), 60°C and 80°C hot water caused a 13.4% and 22.0% decrease in the 28 day tensile strength of plain shotcrete, respectively, and an 11.9% and 16.9% decrease in compressive strength.The tensile strength of hooked-end steel fiber shotcrete decreased by 14.5% and 4.0%, while compressive strength decreased by 6.5% and 1.0%. Wavy steel fiber reinforced shotcrete showed a 25% decrease in tensile strength and an 11.0% decrease in compressive strength at 60° C. In high-temperature hot water environments, shotcrete with 1.0% volume fraction of hooked-end steel fibers exhibited the best performance in enhancing both tensile and compressive strengths.
Abstract：
To investigate the changes in mechanical properties of shotcrete in high-temperature hydrothermal envi? ronments and related improvement measures, tests were conducted on plain shotcrete, shotcrete with hooked-end steel fibers, and wavy steel fibers under three conditions: 20°C (room temperature water), 60°C, and 80°C hot water.The study focused on the splitting tensile strength and uniaxial compressive strength of these shotcrete mixtures.The results show that hot water accelerates the early hydration reaction of concrete and improves early mechanical properties. However, long-term exposure leads to the decomposition and reorganization of C-S-H gel, reduced densification of hydration products, and deterioration of interface performance, which causes a decrease in strength over time. Compared to room temperature (20°C), 60°C and 80°C hot water caused a 13.4% and 22.0% decrease in the 28 day tensile strength of plain shotcrete, respectively, and an 11.9% and 16.9% decrease in compressive strength.The tensile strength of hooked-end steel fiber shotcrete decreased by 14.5% and 4.0%, while compressive strength decreased by 6.5% and 1.0%. Wavy steel fiber reinforced shotcrete showed a 25% decrease in tensile strength and an 11.0% decrease in compressive strength at 60° C. In high-temperature hot water environments, shotcrete with 1.0% volume fraction of hooked-end steel fibers exhibited the best performance in enhancing both tensile and compressive strengths.
YU Li1,
2 QIN Youlin1,
2 CHEN Lanxin1 etc
.Experimental Study on the Macroscopic Mechanical Properties of Steel Fiber Reinforced Shotcrete in High-temperature Hydrothermal Environments[J] MODERN TUNNELLING TECHNOLOGY, 2025,V62(1): 231-241
2025, Vol. 62 