Application of the grey system theory to predict the chloride ion capacity of concrete subjected to salt lake environment

Concrete specimens made with Portland cement at water-binder ratio of 0.35 incorporating 0% mineral admixture or 10% silica fume or 30% fly ash or 50% ground blast furnace slag with the replacement of cement were made and exposed to a wetting-drying salt lake environment. Total chloride ion content and free chloride ion content of specimens were measured. Concrete chloride binding capacity was calculated based on the test data. Effects of wet-dry cycle time, mineral admixtures on concrete chloride binding capacity were studied through the grey relational analysis. Multivariate grey prediction model was established to predict the rule of concrete chloride binding capacity subjected to salt lake environment. The study ranked these effective variables from high to low by silica fume content, fly ash content, ground blast furnace slag content, and wet-dry cycle time. Multivariate grey prediction model shows enough precision to predict the rule of concrete chloride binding capacity subjected to sulfate environment.