Over the last 40 years, the Middle East has seen an exponential growth of construction activity despite harsh climatic conditions and severe marine environments. Experts have observed chloride-induced corrosion of steel reinforcement to be the biggest cause of structural deterioration in existing buildings. It is worth noting that chlorides are said to have been carried over large distances, which means that this problem is not isolated to beach-front structures.
Why Does Concrete Corrode?
Being alkaline in nature, concrete protects the steel reinforcement within it from corrosive elements. Thanks to the concrete’s high pH values, a thin protective layer of stable oxides forms on the metal surface, hindering the development of rust. When the influence of a corrosive environment destroys this protective layer of stable iron oxides, the process of corrosion begins.
The corrosion of reinforced steel causes an increase in its volume, which leads to internal tensions and cracks in the concrete structure. The resulting damage leads to the concrete peeling and causes further damage like:
- Risky stability of the structural element
- Future opportunity for further corrosion of the remaining steel reinforcement
- Reduced fire resistance of the concrete structure
- Physically appearance of the structure
How Can MCI® Technology Stop Concrete Corrosion?
The corrosion of rebar in a deteriorating concrete structure can lead to costly repairs, financial losses, injuries, and even deaths. Cortec® MCI® Technology can significantly extend the service life of concrete structures by delaying the onset of corrosion and keeping the corrosion rates low after treatment initiation. Cortec® MCI® (Migrating Corrosion Inhibitor) solutions maintain structural integrity, rehabilitate vulnerable structures, and alleviate environmental concerns. These migrating corrosion inhibiting products provide concrete corrosion protection against carbonation, chlorides, and other contaminants.
MCI® Technology is crucial in ensuring the longest possible lifespan of concrete in restoration projects. It can slow the corrosion rate in deteriorating structures and help protect against the troublesome aftereffect of concrete repair, i.e. the ring anode/insipient anode effect. MCI® products are convenient to add to concrete repair mixtures and can migrate through adjacent areas after application to protect the embedded steel reinforcement within the concrete.
Based on amine technology, MCI® is classified as a mixed inhibitor that can affect the anodic and cathodic portions of the corrosion cell. It can be applied in many forms, like a concrete admixture or a topical treatment. It is the best corrosion inhibitor for concrete that can move like a liquid through the concrete matrix via the capillary action and migrate in a vapour phase throughout the concrete pore structure. When MCI® molecules come in contact with the embedded metals, there is an iconic attraction that allows for a protective molecular layer to form on the surface. This protective film can prevent corrosive elements from further corroding the reinforced steel and help reduce the existing corrosion rates, thereby greatly extending the concrete structure’s service life.
Conclusion
Time and time again, bridges and overpasses inevitably deteriorate from corrosion of embedded reinforcing metal. Once rusting begins, it can grow to several times the original size of the rebar and cause the concrete to crack and spall off the bridge, eventually compromising the structure. That is why it is imperative that the right measures are taken in a timely manner to prevent dangerous situations.
