29th April 2017


Bridges and overpasses eventually deteriorate from corrosion of embedded reinforcing metal. This can be the result of simple carbonation as air exposure lowers concrete pH and destroys the natural protective layer that exists on freshly embedded rebar; or it can be caused by harsh humid, salt spray, polluted, or snowy environments that persistently attack the integrity of the concrete structure. Once rust begins, it grows to several times the original size of the rebar, causing the surrounding concrete to crack and spall off the bridge, and eventually compromise the structure.

Cortec’s Migrating Corrosion Inhibitors (MCIs) combat these problems by stalling the onset of rebar corrosion and reducing corrosion rates once started. MCIs can be applied as surface treatment or included directly in new concrete as a non-invasive admixture.

In either case, MCIs are able to travel through concrete pores to protect embedded rebar below the concrete surface. The MCI ions are attracted to the metal surfaces where they adsorb and form a monomolecular layer of protection against the ingress of oxygen, chlorides, and other corrosive contaminants. As mixed inhibitors, they provide both anodic and cathodic protection against corrosion.

MCI products can be applied for greater durability at practically any stage of a bridge’s life cycle—whether construction, repair, or maintenance. However, the best results come from proactive protection before corrosion starts.