Corrosion of metal reinforcement is the most important durability concern of concrete infrastructures. In this research, chloride transport in mortars prepared using ternary blends of OPC-calcined clay-limestone (LC3) as the cementitious materials is assessed and compared to a reference OPC system. Three clays with varying kaolinite content (17%, 50% and 80%) were employed. Through XRD analysis, transformation of carboaluminate phases - the stable form of AFm in LC3 binders - to Friedels salt, as a consequence of exposure to NaCl solution was observed. In addition, porosity of LC3 binders, with kaolinite content of 50% and higher was found to be significantly refined, which helps reduction of the depth of chloride penetration. The findings support excellent behavior of LC3 cement, prepared using low-grade clays, in corrosive environments.