Zinc-Rich Primer (ZRP) based coating systems are widely used to protect steel infrastructure from aggressive exposure environments. These coating systems provide corrosion protection of the steel substrate by both barrier and sacrificial mechanism. Electrical continuity between the zinc pigments and steel substrate is the fundamental parameter in order to achieve galvanic protection and the use of high pigment volume concentration may not necessarily ensure effective electrical continuity. Moreover, high zinc content also degrades the bond of the coating matrix to the steel substrate. Carbon nanoparticles are being considered in the development of ZRP coating systems to overcome these limitations considering its physical, electrical and mechanical properties. In this effort, a nanoparticle enriched zinc-rich primer coating system (NPE-ZRP) was evaluated to identify the influence of nano-particles on moisture intrusion of the coating system. A traditional inorganic zinc-rich coating system
(ZRP) was also evaluated to compare the overall performance of the NPE-ZRP coating system. Pre-exposure to the different levels of humidity (5%, 75% & 100% RH) was incorporated to identify the coating robustness and the influence of nano-particles to mitigate corrosion. Environmental pre-exposure to humidity didn’t appear to have a detrimental effect on the coating durability. Both coatings allow moisture intrusion inside the system and EIS can be used as an effective tool to estimate the moisture content.