Low-permeability concretes containing slag and silica fume

Chloride-induced corrosion causes significant deterioration in transportation structures where uncoated reinforcing steel is used. Concretes having a very low permeability are used to prevent the intrusion of chlorides into concrete to the level of the reinforcing steel. This study evaluates the strength and permeability of various combinations of silica fume and slag in concrete. It was determined that when silica fume is added in small amounts (3 to 5 percent) to concretes that have up to 47 percent slag at a water-cement ratio of 0.40 and 0.45, economical concretes with very low permeability and adequate strengths can be produced.