| Another form
of concrete deterioration can occur in bridge decks that undergo freeze-thaw
cycling and are exposed to water and deicing salts. This deterioration
starts at the concrete surface and progresses downward. It tends to be more
severe in older bridges without air-entrained concrete, although scaling can
occur in newer structures that are continuously exposed to moisture and
chlorides. When covered with an asphalt or concrete overlay this type of
deterioration is not readily observed with conventional techniques. |