A comparison study of the performance of three electro-migrating corrosion inhibitors in improving the concrete durability and rehabilitating decayed reinforced concrete

Electro-migration (EM) treatment with injection of corrosion inhibitors is regarded as an efficient method to rehabilitate decayed reinforce concrete architectures and structures. In order to explore the advantages of different electrolytes used in this method, three reported nitrogenous electro-migrating inhibitors: guanidine, 1,6-hexamethylenediamine (HMDA) and 3-aminopropyltriethoxysilane (APS) were selected and their effectiveness on reinforced cement mortar durability were compared. APS and HMDA can more efficiently prevent the external aggressive factors (water, chloride and carbonation) rather than guanidine, while guanidine shows advantage in recovering the mortar alkalinity after EM treatment. To select the appropriate electro-migrating corrosion inhibitors, not only the inhibitive effect, but also their effectiveness on removing chloride and re-alkalization and enhancing the resistance to external aggressive factors should be taken into account.