Long-term temperature acceleration effect of solar radiation heating on chloride transport in the CRTS III multilayer structure

Abstract

The service life of high-speed railway track structures located in coastal areas may be shortened by chloride erosion due to the marine environment. This study aims to simulate chloride transport within the track structure by boundary condition models based on high-precision climate data and structural damage. The established numerical models consider various factors, including structural damage, historical exposure data of air temperature and relative humidity, temporal resolutions, solar radiation history, and the deposition rate of atmospheric chloride. The main conclusions are as follows: The maximum vertical temperature gradient of the track slab is roughly 81K/m, and the daily average temperature differences between air and surface concrete in July and February are around 9.6°C and 4.8°C, respectively. The chloride flux boundary derived from the chloride deposit rate is nearly 1 × 10-9mol/(m2s) to 10 × 10-9mol/(m2s) under a marine atmospheric environment. Step functions of daily average and monthly average temperature can improve almost the same prediction accuracy of chloride diffusion, and increasing the monthly average temperature curve by 10°C can roughly estimate the upper limit of temperature acceleration.