Abstract
Corrosion of reinforcing bar in concrete is influenced by various factors such as moisture state of concrete, supply situation of oxygen, etc. The influence of void on bottomsurface of reinforcing bar on corrosion of reinforcing bar has been reported among several research papers, however, most of them are qualitative not quantitative.
Deterioration due to chloride attack is often recognized after appearance of crack of concrete by corrosion of reinforcing bar, however, it is very difficult to repair damaged concrete to the sound initial condition, and also the cost of repair becomes much expensive. So, it is important to diagnose by nondestructive procedure, and to understand the corrosion state of reinforcing bar in doing efficient maintenance management of concrete structure.
In this study, the influence of the void on bottom surface of the reinforcing bar on corrosion of reinforcing bar is examined experimentally.
The results obtained in this study are as follows,
1） The void on the bottom surface of reinforcing bar becomes larger at the position near the casting surface. Vickers hardness becomes lower at the position of large air void.
2） There is a possibility that the corrosion initiates even when chloride content around the reinforcing bar is low with relatively large air void. Therefore, the threshold chloride content for corrosion initiation should be discussed considering the condition of air void around the reinforcing bar.
3） Within this experiment, electro-chemical measurements, half-cell potential, and polarization resistance could not reflect the air void situation in their measured data.
