Sulfate attack on concrete: A case history

The study of the case history presented in the paper shows that the excessive concentration of sulfates in soil and groundwater which would come in contact with the concrete may not be considered as the only index to determine if the sulfate attack on the concrete would be imminent. In certain conditions, the cause of the sulfate attack may lie within the concrete mass rather than in the outside soil-water conditions. Also in certain environments, particularly if the concrete is porous, the apparently harmless amounts of sulfates salts in soil-water may rise into concrete in a dilute solution form due to capillary action, whereupon evaporation of water, the sulfate concentration may increase to an extent which would activate the sulfate attack. Capillary moisture also provides chemical environment for the dry sulfates which may be occurring within the hardened concrete mass to start reaction causing deterioration of concrete.