Mechanical Properties and Durability of Concrete Made with Blended Fly Ash

Abstract

This study focused on evaluating the effects of blended fly ash on mechanical properties and durability of concrete. In this investigation two reference mixtures were used. One was a mixture without fly ash, and the other contained 35% ASTM Class C fly ash. Additional mixtures were composed of three blends of ASTM Class C and Class F fly ash while maintaining a total fly ash content of 40% of the total cementitious materials. Mechanical properties such as compressive strength, tensile strength, flexural strength, and modulus of elasticity were determined. Durability related properties determined were drying shrinkage, abrasion resistance, salt scaling resistance, and electrical prediction of chloride ion penetration. The results showed that blending of Class C fly ash with Class F fly ash showed either comparable or better results than either the reference mixture without fly ash or the unblended Class C fly ash. Blending of fly ash, therefore, leads to comparable or better quality and reduced cost, attributed to the use of Class F versus Class C fly ash in concrete.