Corrosiom behaviour of Reinforced steel in presence of mineral and chemical admixtures in seawater

Abstract

Admixtures, mineral or chemical, are materials that are added to concrete batch immediately before or during mixing in order to modify the physicochemical and mechanical properties of the product. The corrosion behaviour of reinforced steel embedded in cement pastes incorporating different amounts of silica fume as a partial replacement and various contents of chemical admixtures has been studied in 3.5% NaCl solution. The results show that, the diffusion rate of chloride ions is reduced due to improved effect of pore solution structure and capacity of cement paste to bind chloride chemically. It is desired to use chemical admixtures to reduce the water/cement ratio, which is the dominant factor controlling steel corrosion. It was found that, the reinforced steel embedded in cement pastes incorporating different amounts of silica fume with various contents of chemical admixtures, manifested a high degree of passivation on soaking the samples in the investigated media. The effectiveness of each admixture on its type and its concentration.