| Title |
Effects of Silica Fume on Choloride Binding and Intrusional Resistance |
| Abstract |
Chloride ion is considered one of the most common culprits in the corrosion of steel in concrete. It breaks down the passive film and allows the steel to corrode actively at a high rate. The "internal CI-" in concrete is CI- which is introduced at the mixing stage and the "external CI-" in concrete is CI- which intrudes into concrete from the surrounding environment. The main objective of this study is to determine the critical chloride ion concentrations in the pore solutions of cement pastes and to quantify the depth and amount of chloride ion intrusion in mortars made with and without silica fume. Cement pasts and mortars with water-ratio of 0.5 were prepared with silica fume replacement 0, 10, 15 percent. The pastes were allowed to hydrate in sealed containers for 28 days and to express pore solution. Mortars were stored in substitute ocean water for 60 days. The expressed pore fluids were analyzed for chloride and hydroxyl ion concentrations. It was found that the chloride binding capacity decreases significantly with an increase in silica fume replacement ratio. But the intrusion depth and amount of chloride ion in mortars decreases significantly with an increase in the silica fume replacement ratio. |