Enhanced passivation of galvanized steel bars in nano-silica modified cement mortars

This work investigated the electrochemical behavior of galvanized steel bars in nano-silica modified cement mortars. The internal environmental factors of the mortar were firstly characterized. Then the passivation process of the galvanized steel bars was monitored. The results showed that the presence of nano-silica influenced the passivation process of galvanized steel bars and improved the protective properties of passive film. The morphology of passive film was changed, and the thickness was increased by the addition of nano-silica. The CHZ layer performed as a bonding agent between the galvanized steel and mortar matrix. The addition of nano-silica promoted the formation of gaps at the rebar/mortar interface, and there was no evidence for the presence of a lime-rich layer at the interface.