Effects of Fly Ash on Strength and Durability of Hydraulic Structures with Various Grades of Cement and Concrete

The effects of cement and sand replacement by two classes of fly ash (C and F) on the strength and durability characteristics of concrete made using three grades of cement are discussed. The compressive strength, permeability, and sulfate resistance of a large number of samples made from three grades of ordinary concrete - common to hydraulic structures - were studied. Effects of cement and sand replacement (10%, 15%, and 20%) by the two types of fly ash were compared with the results from control specimens. They show the dependence of durability characteristics - permeability and sulfate resistance - on the class and fineness of fly ash, the grade of concrete, the amount and type of replacement, and, to a lesser degree, on the grade of cement.