Chloride penetration and electrical resistivity of concretes containing nanosilica hydrosols with different specific surface areas

In this study, the influence of nanosilica hydrosols with specific surface areas of 100 m2/g, 200 m2/g and 300 m2/g and silica fume with specific surface area of 21 m2/g on chloride permeability and electrical resistivity of concrete is investigated. The results indicate that the nanosilicas, especially at higher replacement levels, enhanced the chloride and electrical resistance of concrete at early ages, while silica fume did not have a significant influence on these characteristics at early ages. The results also show that the nanosilicas with lower surface areas had better performance in enhancing the chloride and electrical resistance of concretes compared to the finer ones, especially at 28 days and 90 days. Silica fume achieved a similar performance to the best performing nanosilica at 28 days and surpassed it at 90 days.