ABSTRACT

Deterioration of concrete may be caused by chemical and physical processes, or their combination. Chemical mechanisms include leaching of paste components, carbonation of calcium hydroxide and C-S-H, paste deterioration by exposure to aggressive chemicals (acids, agricultural chemicals, sulfates), corrosion of steel reinforcement, and alkali-aggregate reactions. Physical or mechanical causes of concrete deterioration are represented by abrasion, erosion, cavitation and, most important, by freezing and thawing cycles. Most chemical mechanisms of deterioration involve damage to the cement paste matrix, but deterioration of the paste-aggregate interface, the aggregate itself, or the pore structure often accompanies the paste deterioration. Sulfate attack, the subject of this monograph, is a form of chemical mechanism.