ABSTRACT
The corrosion of steel in concrete is probably the most widespread and serious durability problem in North America and wherever chloride based deicing salts are used. Before 1919, concrete mix design was a rather arbitrary procedure, with no specific guidelines on how to develop a suitable mix. Concrete exposed to repeated cycles of freezing and thawing when in a saturated or near-saturated state is susceptible to severe damage if appropriate measures are not taken. Sulfate attack is one of the most common and widespread forms of chemical attack on concrete. Sulfates are often present in soils and groundwaters, or may derive from industrial wastes such as mine tailings. The alkali–aggregate reaction (AAR) refers to a reaction between alkalis in the cement and certain types of aggregate. The main types of these reactions are the alkali–silica reaction (ASR), and the alkali–carbonate rock reaction (ACR).
