Non-uniform Corrosion and Load Bearing Capacity Deterioration Tests of Reinforced Concrete Beams Under Load and Chloride Salt Environment

To explore how sustained loading and drying-wetting cycles of chloride salt affect the flexural behavior of reinforced concrete (RC) beams, the corrosion tests and flexural capacity tests of 19 RC beams were carried out at first. The effects of various sustained loading grades and drying-wetting cycle periods were studied on the crack distribution, the mass corrosion rate of longitudinal reinforcements, and the flexural behavior of corroded members. The relationship was summarized between the maximum and average mass corrosion rate of longitudinal reinforcements and the flexural bearing capacity reduction ratio. The study results show that the corrosion degree of longitudinal reinforcements was higher in the pure bending segment than in other areas, and distributed non-uniformly along the circumference of the longitudinal reinforcements. There was no noticeable correlation between the position of the extreme mass corrosion rate of longitudinal reinforcements and the occurrence position of initial transverse cracks. The maximum mass corrosion rate of longitudinal reinforcements increased with the loading grade and drying-wetting cycle period, and was more notably affected by the drying-wetting cycle period. The peak load of the beam decreased after corrosion. When the mass corrosion rate of the longitudinal reinforcements was low (average value below 3% or maximum value above 6%), the correlation between the mass corrosion rate and the reduction ratio of bearing capacity was low, and the maximum mass corrosion rate has less correlation with the reduction ratio of bearing capacity than the average mass corrosion rate. When the mass corrosion rate of longitudinal reinforcements increased (average value above 3% or maximum value above 6%), both the maximum and the average mass corrosion rates of longitudinal reinforcements had an increased correlation with the reduction ratio of bearing capacity. When the average mass corrosion rate of longitudinal reinforcements is the same, the reduction of bearing capacity of specimens with natural corrosion is higher than that of specimens with external current corrosion.