Performance Degradation And Failure Characteristics Of Corroded RC Components

With the rapid development of economy and society, the transportation between regions is increasing and the national government also spent quantities of fund in the transportation construction. As a key part of transportation, bridge is very important to the road communication safety, and it is the lifeline project to the society and economy.Currently, the reinforcement bar corrosion is one of the most common deterioration of reinforced concrete bridges, which reduce the intersection area of steel bar, and weaken the bond property between steel and concrete, which is the premise to ensure steel and concrete can work well, and it have a significant impact on the structure. Because of the small stirrups diameter and the thin concrete cover, so its corrosion is always severe than the others reinforcement. Brittle failure caused by hoop corrosion during the use t is extremely dangerous, because it has no sign, leading to disastrous consequences than flexure failure. However, there is little study about it.Aim to the inadequate of previous studies, this paper carried out as follows:(1) Introduced the mechanism of steel corrosion and the method to carry out fast electrochemical corrosion, which offer necessary methods for mechanical property and the assessment of reinforced concrete bridges and others structures.(2) Discussed the bond mechanism and the degradation mechanism of bond properties of reinforced concrete structures.(3) Based on the existing pullout tests on the bonding specimens with the deformed steel installed by the interior strain gauge are conducted. The different reinforcement strains are obtained and the bond stresses between reinforcement and concrete are derived. The effect of the corrosion rate on the bond stress between reinforcement and concrete is analyzed.(4) The main failure characteristics of the beams and the impact of corrosion rate of stirrup on existing RC beams were introduced based on the load test of existing RC beams, which provided some foundation for the evaluation of durability of existing reinforced concrete bridge structures.