Serviceability of spillway concretes in southwestern Saskatchewan

Concrete condition surveys were performed on a number of spillways of Saskatchewan dams to obtain information on the present condition of the concrete, to identify and determine cause and extent of any deficiencies, and to outline repair conditions. The concrete mixes used for early structures were mostly designed with a water/cement ratio of 0.57-0.60, which was lowered to 0.50 for structures built after 1952. Compressive strength of most concrete cores ranged between 25 and 50 megapascals. Some low stregth values were also obtained, and these concretes were generally showing distress. The major cause of the distress was deterioration resulting from feeezing and thawing. Damage to one structure was attributed to both freezing and thawing and sulfate attack. Estimates were made of the future life expectancies of each of the spillway structures from a concrete materials standpoint. Based on these estimates and using the present age of the structures, projected service life of the different spillways ranged from 60-90 years. 13 refs., 1 fig., 8 tabs