Effect of Deicing Salts on Deterioration and Dimensional Changes of Carbonate Rocks

The deleterious effect of deicing salts on concrete has long been recognized. This study deals with effect of salt solution treatment on the expansivity and durability of carbonate rocks.

Two groups of carbonate rocks from operating quarries of Southwestern Ontario were tested for their durability by magnesium sulfate and freeze-thaw test methods. The silica and the alumina content were determined, as well as the water adsorption after treatment in 3 weight percent chloride salt solution. Isothermal expansion upon wetting of the dry treated and untreated rocks also were studied.

The results indicate that the carbonate rocks show a direct, significant relationship between isothermal length change on wetting and clay content, water adsorption, and durability. Clay and chert content, and water adsorption were found to be reliable indicators of rock durability. Water adsorption before and after salt treatment could be used to predict the effect of deicing salts on the durability of rocks.