Studies on the Properties of Super Workable Concrete Using Ground Granulated Blast-Furnace Slag

This report presents the properties of hardened super workable concrete in which ground granulated blast furnace slag was used, and compares these properties with the corresponding properties of ordinary concrete. Two ground granulated blast furnace slags of fineness 4500 cm squared/g and 6150 cm squared/g were used for this research. The replacement ratio of cement by blast furnace slag were controlled to 0%, 30%, 50%, and 70%. The concrete specimens were cured by four different methods; in air continuously, in water for 3 days and then in air, in water for 7 days and then in air and in water continuously. The super workable concretes, which were cured in water sufficiently at early ages, exhibited higher performance in compressive strength, water permeability, resistance to freezing and thawing and carbonation in comparison with ordinary concrete. As for the porosity as well, the total pore volume of these concretes were lower than that of ordinary concrete. This excellent performance was more remarkable in the super workable concrete with blast furnace slag of fineness of 6000 cm squared/g. But, these properties of super workable concrete with blast furnace slag were more sensitive to initial water curing period than the concrete without blast furnace slag.