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<p>To investigate the freeze-thaw degradation mechanism and damage evolution of fiber-reinforced concrete in high-altitude cold regions, this study relies on a transportation infrastructure project in Nagqu, Xizang. Through sequential freeze-thaw cycling tests and Nuclear Magnetic Resonance (NMR) analysis, the deterioration patterns of mass, dynamic elastic modulus, ultrasonic wave velocity, flexural strength, and pore structure of ordinary fiber concrete (NC), abrasion fiber concrete (CM), and expansive fiber concrete (PZ) under freeze-thaw cycles in high-altitude environments were systematically analyzed. A freeze-thaw damage model suitable for low-pressure plateau conditions was established. The results indicate that: (1) CM exhibited the optimal freeze-proof durability, maintaining relatively intact appearance after 300 freeze-thaw cycles, while PZ and NC failed after 175 and 225 cycles, respectively. After freeze-thaw cycles, the mass loss rate, relative dynamic elastic modulus, ultrasonic wave velocity, and flexural strength of CM decreased by 1.16%, 49.18%, 65.01%, and 39.38%, respectively. (2) The freeze-proof durability of the three fiber-reinforced concretes was positively correlated with the proportion of small pores (&lt; 0.01&#xa0;μm) and medium pores (0.01 ~ 0.05&#xa0;μm), and negatively correlated with the proportion of large pores (0.05 ~ 0.1&#xa0;μm) and cracks (&gt; 1&#xa0;μm). Before freeze-thaw cycles, CM had the highest total proportion of medium and small pores at 67.58%, compared to 56.30% for PZ and 61.73% for NC. Upon freeze-thaw failure, the total proportion of medium and small pores in the three specimens decreased to 44.78%, 41.78%, and 40.26%, respectively, while the crack proportion increased significantly. (3) By introducing an atmospheric pressure influence coefficient, a freeze-thaw damage model based on dynamic elastic modulus was established. The average error between the predicted flexural strength values from the model and the measured values was less than 5%, demonstrating the model’s reasonableness and feasibility. These findings indicate that incorporating anti-abrasion agents into fiber concrete effectively enhances its freeze-proof durability in high-altitude cold environments.</p>

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Investigation of Freeze-Proof Durability and Damage Model of Fiber Concrete in High Altitude and Cold Region

  • 期刊论文

  • 发表日期：

    2026年5月18日

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  • Xianghui Deng,
  • Chong Liu,
  • Rui Wang,
  • Bangxuan Zhao,
  • Yong Wu,
  • Xing Guo,
  • Lihua Deng

摘要

To investigate the freeze-thaw degradation mechanism and damage evolution of fiber-reinforced concrete in high-altitude cold regions, this study relies on a transportation infrastructure project in Nagqu, Xizang. Through sequential freeze-thaw cycling tests and Nuclear Magnetic Resonance (NMR) analysis, the deterioration patterns of mass, dynamic elastic modulus, ultrasonic wave velocity, flexural strength, and pore structure of ordinary fiber concrete (NC), abrasion fiber concrete (CM), and expansive fiber concrete (PZ) under freeze-thaw cycles in high-altitude environments were systematically analyzed. A freeze-thaw damage model suitable for low-pressure plateau conditions was established. The results indicate that: (1) CM exhibited the optimal freeze-proof durability, maintaining relatively intact appearance after 300 freeze-thaw cycles, while PZ and NC failed after 175 and 225 cycles, respectively. After freeze-thaw cycles, the mass loss rate, relative dynamic elastic modulus, ultrasonic wave velocity, and flexural strength of CM decreased by 1.16%, 49.18%, 65.01%, and 39.38%, respectively. (2) The freeze-proof durability of the three fiber-reinforced concretes was positively correlated with the proportion of small pores (< 0.01 μm) and medium pores (0.01 ~ 0.05 μm), and negatively correlated with the proportion of large pores (0.05 ~ 0.1 μm) and cracks (> 1 μm). Before freeze-thaw cycles, CM had the highest total proportion of medium and small pores at 67.58%, compared to 56.30% for PZ and 61.73% for NC. Upon freeze-thaw failure, the total proportion of medium and small pores in the three specimens decreased to 44.78%, 41.78%, and 40.26%, respectively, while the crack proportion increased significantly. (3) By introducing an atmospheric pressure influence coefficient, a freeze-thaw damage model based on dynamic elastic modulus was established. The average error between the predicted flexural strength values from the model and the measured values was less than 5%, demonstrating the model’s reasonableness and feasibility. These findings indicate that incorporating anti-abrasion agents into fiber concrete effectively enhances its freeze-proof durability in high-altitude cold environments.