<p>Wind load caused by the high-speed running train is the typical environmental factor for ballastless track supporting layer concrete. Herein, the effect of wind load on the internal relative humidity (IRH), volume stability and mechanical properties of supporting layer concrete were investigated by a designed device to produce stable wind loads. Mercury intrusion porosimeter (MIP) and scanning electron microscopy (SEM) were used to analyze the evolution of the microstructure and the morphology of hydration products. Results show that, under a wind velocity of 10 m/s, the IRH at a depth of 2 cm decreases to 35.9% within 10 days, leading to a 40.1% higher shrinkage compared to that under windless environment. Meanwhile, the volume of specific pores (200 – 10 000 nm) is increased by 18.2%, which results in a 24.3% reduction in compressive strength and a weaker interfacial transfer zone (ITZ). Additionally, a model for IRH and internal restraint stress of supporting layer concrete under wind load was developed. This work can provide a reference for the design and maintenance of ballastless track supporting layer concrete.</p>

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Performance Evolution of High-speed Railway Ballastless Track Supporting Layer Concrete: Influence of Wind Loads

  • Zhonglai Yi,
  • Yuxuan Ji,
  • Zhiqiang Yang,
  • Guanhong Liu,
  • Na Zhang,
  • Huajian Li

摘要

Wind load caused by the high-speed running train is the typical environmental factor for ballastless track supporting layer concrete. Herein, the effect of wind load on the internal relative humidity (IRH), volume stability and mechanical properties of supporting layer concrete were investigated by a designed device to produce stable wind loads. Mercury intrusion porosimeter (MIP) and scanning electron microscopy (SEM) were used to analyze the evolution of the microstructure and the morphology of hydration products. Results show that, under a wind velocity of 10 m/s, the IRH at a depth of 2 cm decreases to 35.9% within 10 days, leading to a 40.1% higher shrinkage compared to that under windless environment. Meanwhile, the volume of specific pores (200 – 10 000 nm) is increased by 18.2%, which results in a 24.3% reduction in compressive strength and a weaker interfacial transfer zone (ITZ). Additionally, a model for IRH and internal restraint stress of supporting layer concrete under wind load was developed. This work can provide a reference for the design and maintenance of ballastless track supporting layer concrete.