Resistance Performance of Concrete Using both Blast Furnace Slag Cement and Fly Ash against Chloride Attack and Carbonation

Abstract

From the viewpoint of effective utilization of industrial wastes and reduction of CO2 emission, the use of concrete mixed with blast furnace slag and fly ash has been promoted. However, the durability of fly ash concrete using blast furnace slag cement has not been clarified enough. About chloride attack, the resistance against the penetration of chloride ions could be improved due to the dense pore structure formed by the synegetic effect of mixing both ground granulated blast-furnace slag and fly ash into concrete. In this study, resistance performance of concrete using both blast furnace slag cement and fly ash against chloride attack and carbonation was experimentally investigated. The relationship between such resistance performance and pore structure of the concrete was also examined. As a result, the combination of blast furnace slag cement and fly ash type II resulted in the decrease of pore volume over 50 nm in the diameter and reduction of the apparent diffusion coefficient of chloride ion, but the resistance performance against carbonation of the concrete was lower than the case of the normal fly ash concrete.