Liu Xiaochun, Li Haihua, Qi Min, Yang Yiyi, Zhu Zhihui, Yu Zhiwu
National Engineering Research Center for High Speed Railway Construction, Central South University, Changsha 410075, China.
School of Civil Engineering, Central South University, Changsha 410075, China.
Materials (Basel). 2023 May 4;16(9):3524. doi: 10.3390/ma16093524.
The concrete track slab and the base slab of the high-speed railway CRTS II track structure are prone to transverse cracks in the initial service period, which are subjected to environmental action and train load. In order to investigate the influence of transverse cracks on chloride ingress of concrete track slab and base slab in a coastal environment, drying-wetting cycle chloride erosion tests were carried out on reinforced concrete track slab and base slab specimens with cracks ranging from 0 mm to 0.6 mm, subjected to continuous bending moment. The chloride ion concentration of concrete along the depth direction was collected during the test process. The experimental results show that the chloride ion concentration of concrete at the crack section is much higher than that at the intact section, and it increases with the increase of crack width in the range of 0.2 mm to 0.6 mm. A chloride diffusion coefficient model of cracked concrete is proposed for slab track based on the experimental results, which can comprehensively consider the effects of surface chloride ion concentration, chloride binding effect, time-varying effect, temperature, relative humidity, and transverse crack width.
高速铁路CRTS II型轨道结构的混凝土轨道板和底座板在初始服役期容易出现横向裂缝，这些裂缝会受到环境作用和列车荷载的影响。为了研究沿海环境中横向裂缝对混凝土轨道板和底座板氯化物侵入的影响，对承受连续弯矩、裂缝宽度在0mm至0.6mm范围内的钢筋混凝土轨道板和底座板试件进行了干湿循环氯化物侵蚀试验。在试验过程中收集了混凝土沿深度方向的氯离子浓度。试验结果表明，裂缝截面处混凝土的氯离子浓度远高于完整截面处，且在0.2mm至0.6mm范围内随裂缝宽度的增加而增大。基于试验结果，提出了一种适用于板式轨道的开裂混凝土氯离子扩散系数模型，该模型能综合考虑表面氯离子浓度、氯离子结合效应、时变效应、温度、相对湿度和横向裂缝宽度的影响。
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