2019 Volume 30 Pages 77-84
In this study, we investigated the durability of high-volume ground granulated blast furnace slag (GGBS) blended cement concrete containing over 70％ of GGBS for possible general structural applications. The concrete specimens used were exposed to natural outdoor conditions for 41 years on a building rooftop. It was found that the carbonation depth of concrete specimens containing 70％ GGBS was about 7 to 9 mm, and about 15 mm for specimens containing 90％ GGBS. Despite the high volume of GGBS content (70％) in the concrete specimens, traces of Ca(OH)2, which is involved in the chemical reaction of GGBS, were found in parts that remained uncarbonated. Ca(OH)2 increases the alkalinity of the specimen and is thus considered to have a rebar corrosion-inhibiting effect.
