But concrete can suffer from a more pernicious type of damage. This occurs when lots of water gets into concrete and starts to eat away at the steel reinforcement. The rust expands inside the structure, creating further cracking, and the whole internal steel skeleton can be compromised. It is particularly likely to happen in the presence of saltwater, which destroys the iron hydroxide protection and rusts the steel aggressively. Concrete bridges and roads in cold countries, which are regularly exposed to salt (such as is used to clear snow and ice), are vulnerable to this type of chronic
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The reason the internal steel skeleton within concrete doesn't erode is because they expand and contract at nearly the same exact rate.
