Influence of pre-exposure fatigue loading on chloride penetration in concrete specimens with epoxy-coated reinforcement

The paper presents results of an experiment study of chloride penetration into concrete specimens with epoxy-coated reinforcement. The test specimens were made of ordinary Portland Cement (PC) concrete with w/c ratio of 0.44 and reinforced with uncoated and epoxy-coated reinforcing bars. For the latter two nominal coating thicknesses: 200 µm and 600 µm, were chosen. The specimens were divided into three groups and then the specimens from two groups were subjected to different fatigue loads. After that all specimens were repeatedly fully immersed in 3.5%~ 5% NaCl solution and dried; these wetting/drying cycles simulating seawater attack continued for 388days. Four ϕ100×120-mm cylinders were then drilled out from the bottom side of the central 300-mm long zone of each specimen. The cylinders were used to measure chloride profiles within the concrete cover. Results of the measurements are presented in the paper. The apparent chloride diffusion coefficient and surface chloride concentration of each sample were estimated by fitting a solution of Fick’s 2nd law of diffusion to the measured chloride profiles. It can be concluded that the chloride content at the bar level and the apparent chloride diffusion coefficient are influenced by pre-exposure fatigue loads, especially in the specimens with epoxy-coated reinforcement. It is also interesting to note that according to the test results undamaged specimens with epoxy-coated reinforcement had lower chloride diffusivity than those with uncoated reinforcing bars.