Semnan University Press Journal of Transportation Infrastructure Engineering 2423-5350 5 4 2019 12 22 Development of a Corrosion Prediction Model for B70 Concrete Sleepers on Iranian Desert Railway Development of a Corrosion Prediction Model for B70 Concrete Sleepers on Iranian Desert Railway 31 56 4173 10.22075/jtie.2019.18879.1425 FA Morteza Esmaeili School of Railway Engineering, Iran University of Science and Technology (IUST) Sadegh Kaviani Railway Track & Structures Engineering ِDepartment, School of Railway Engineering, Iran University of Science and Technology, Tehran, Iran Mohsen Tadayon Faculty Member of Bu Ali Sina University of Hamedan and Chairman of the Board of Iranian Concrete Association, Tehran Journal Article 2019 10 07 Nearby 600 kilometers of Iran Railway is located in sandy desert areas. The most critical problems of railway superstructure in these areas are corrosion of rail, fastening system components such as bolts and clips, as well as early cracking and breakage of concrete sleepers. Studies have shown the ingress of chloride ions, from desert soil into the concrete sleeper in the presence of moisture, which leads to corrosion of pre-stressed steel tendons and eventually to concrete sleeper failure. Nevertheless, there has not been much research into the failure and early cracking of such concrete sleepers, and no model for predicting corrosion of steel has been proposed. In this study, the chloride diffusion in concrete sleepers has been investigated in field and laboratory, and a model has been proposed for predicting corrosion initiation and chloride diffusion. For this purpose, the diffusion coefficients and the initial and surface chloride contents were obtained by sampling from concrete sleepers of Roodshour - Shuregaz block in Bam - Zahedan line. The diffusion coefficient at early ages was obtained by making cubic samples, and then a model was developed based on these parameters. Sensitivity analysis was also performed to investigate the influence of effective factors on the initiation time of the corrosion. From this model, the corrosion initiation time for concrete sleepers is calculated to be 8.5 months. In the sensitivity analysis, the chloride ion diffusion coefficient and concrete cover were the most influential factors on the corrosion initiation time. Nearby 600 kilometers of Iran Railway is located in sandy desert areas. The most critical problems of railway superstructure in these areas are corrosion of rail, fastening system components such as bolts and clips, as well as early cracking and breakage of concrete sleepers. Studies have shown the ingress of chloride ions, from desert soil into the concrete sleeper in the presence of moisture, which leads to corrosion of pre-stressed steel tendons and eventually to concrete sleeper failure. Nevertheless, there has not been much research into the failure and early cracking of such concrete sleepers, and no model for predicting corrosion of steel has been proposed. In this study, the chloride diffusion in concrete sleepers has been investigated in field and laboratory, and a model has been proposed for predicting corrosion initiation and chloride diffusion. For this purpose, the diffusion coefficients and the initial and surface chloride contents were obtained by sampling from concrete sleepers of Roodshour - Shuregaz block in Bam - Zahedan line. The diffusion coefficient at early ages was obtained by making cubic samples, and then a model was developed based on these parameters. Sensitivity analysis was also performed to investigate the influence of effective factors on the initiation time of the corrosion. From this model, the corrosion initiation time for concrete sleepers is calculated to be 8.5 months. In the sensitivity analysis, the chloride ion diffusion coefficient and concrete cover were the most influential factors on the corrosion initiation time. https://jtie.semnan.ac.ir/article_4173_e6fd11df17bcc885746221fad5b1be93.pdf