Durability properties of concrete containing 50% and 65% slag

The method of incorporating slag of normal fineness in concrete has an important bearing on the durability properties of that concrete. In this paper tests are reported to determine some of the durability aspects of concrete containing 50% and 65% of slag replacement, exposed to different curing environments. The mix proportioning of the slag concretes was carried out in such a way that they had low water–binder ratios and high workability, and developed compressive strengths similar to concrete without slag from 3 days onward. The pore size distribution, microstructure and carbonation penetration, as affected by curing regime, of these concrete and their resistance to alkali–silica reaction are reported. The results show that initial water curing of about 7 days prior to exposure to a drying environment is essential to minimise the damage to microstructure that influence the durability of the slag concretes. The data also show that even when exposed to an aggressive environment, slag concretes have a refined pore structure compared to normal concrete, and a better resistance to deterioration.