ABSTRACT
Abstract The formation of hexagonal and cubic calcium ferrite hydrates in the interfacial transition zone between corroded steel and cement paste seems to be a very important factor for the improvement of physical and mechanical characteristics of the bond between concrete and reinforcement. The results of the study show that the chloride ions in the cement paste accelerate significantly the crystallization of the hexagonal calcium ferrite hydrate. With the increase of the concentration of chloride ions in the ITZ a complete series of solid solutions between calcium ferrite hydrates and calcium chloroferrite hydrates is formed. These new crystalline products fix an important part of free chloride ions in the ITZ and could reduce consequently the risk of chloride induced corrosion for the embedded reinforcement. Keywords: Interfacial transition zone, corroded reinforcement, corrosion layer, cement paste, microstructure, calcium ferrite hydrate, chloride ions, calcium chloroferrite hydrate, solid solution.
