Corroding Rebar in Concrete – Costly Repairs

Cortec Corporation’s patented MCI®(Migrating Corrosion Inhibitor™) Technology provides superior corrosion protection for reinforcing metal in concrete.

MCI® greatly extends the service life of new and existing structures by proactively delaying the onset of corrosion and keeping rates low after initiation. MCI® products also maintain structural integrity, rehabilitate vulnerable structures, and alleviate environmental concerns.

Corrosion in Concrete

Often, corroding rebar in deteriorating concrete is the cause of costly repairs, financial losses, and injuries. Corrosion occurs in concrete due to an electrochemical process, which can be formed in two ways:

  • When two dissimilar metals are embedded in the concrete or when significant variations exist in surface characteristics of the steel.
  • Or due to differences in concentration of dissolved ions near steel, such as alkalis, chlorides, and oxygen.

How does MCI® work?

MCIs are based on amine technology (amine alcohols and amine carboxylates). They are classified as mixed inhibitors, meaning they affect both anodic and cathodic portions of a corrosion cell.

A S Harrison & Co Anode Cathode Diagram

MCI® is applied in many forms including as a concrete admixture or a topical treatment. It moves like a liquid through the concrete matrix via capillary action and migrates in a vapour phase throughout the concrete pore structure.

When MCI® comes in contact with embedded metals, it has an ionic attraction to it and forms a protective molecular layer. This film prevents corrosive elements from further reacting with the reinforcement, whilst reducing existing corrosion rates, greatly extending concrete service life.

MCI® Applications

We can provide you with a range of MCI® products, including a variety of admixtures, surface treatments, repair grout and mortars.


Admixtures are designed for addition to concrete during the mixing process. It’s an excellent solution for concrete restoration or in new projects and extends useful service life.

In contrast to other admixtures which rely on pore blockers or are limited by a chloride threshold, MCI® admixtures work independently of chlorides.

MCI® admixtures can protect even when cracks occur and can delay setting time (if required) for better workability. They do not affect the physical properties of concrete when used at the recommended dosage rates.

Topical (Surface) Treatment

MCI® can be applied to existing structures as a surface treatment that reduces corrosion rates. This surface treatment is designed to penetrate and migrate through cementitious materials to reach and protect the embedded reinforcing metal.

MCI® surface treatments can be applied to vertical and overhead surfaces, as well as horizontal surfaces. MCI® provides corrosion protection to embedded rebar from corrosive elements with or without the use of sealers. A range of MCI products also include a sealant to add extra protection.


MCI® is important for ensuring the longest possible lifespan of concrete restoration projects. MCI® not only slows the rate of corrosion in deteriorating structures but also protects against the troublesome ring anode/insipient anode effect that often follows concrete repairs.

MCI® is easily added concrete repair mixtures and migrates through adjacent areas after application to protect embedded reinforcement. MCI® is also available as a passivating grout for use on exposed rebar, or as a topical treatment to existing concrete surfaces.

Durability Sustainable construction

By using MCI® in severely corrosive environments, structures will have a stronger resistance to corrosion and therefore possess greater durability. Increased durability will mean fewer repairs, greater structural integrity, and a longer service life, all leading to greater sustainability.

Sustainable construction

Cortec’s MCI® products not only provide corrosion protection to metals on both new and existing structures, they benefit our environment. Cortec admixtures are derived from renewable resources, and many of Cortec products also meet NSF Standard 61 approval for use in structures holding potable water.

Contact us for more information.


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