Corrosion on Integral Industrial Concrete Assets

The integral industrial concrete assets in process plants are exposed to aggressive corrosion due to the porous nature of concrete. This permits various particles to penetrate through the concrete and corrode the metal rebar.

Corrosion of metal rebar results in severe cracking, thus causing the concrete to weaken and further paving the way for moisture and unwanted particles to penetrate through the structure. If left unattended, this can even result in complete failure of the civil/concrete structures.

The acceleration of corrosion on integral industrial concrete assets depends on the pH level of the concrete. Usually, concrete has a very high pH value ranging between 12 to 13 that forms a protective oxide film that prevents dissolution of metal ions.

Additionally, another major problem is carbonation – when carbon dioxide (CO2) in the atmosphere reacts with the hydroxides present in concrete, the pH value of concrete decreases below 10, which makes the oxide film weak and makes the reinforcement vulnerable to corrosion. Carbonation also reduces the concrete’s resistance to chloride ions that accelerate the deterioration of the oxide film. The usual amount of chloride ions required for initiating corrosion in concrete structures is 7000 to 8000 parts per million (ppm), but when the pH value of the concrete drops between 10 to 11, the number of chloride ions required to initiate corrosion drops down to 100 ppm.

Severe corrosion damages to concrete structures result in heavy direct & indirect costs for the operating unit. These vary from heavy capital/replacement costs, frequent repair & maintenance costs, and prolonged downtime costs.

Adapting a robust, well-engineered concrete repair & rebuild 100% Solid Epoxy system can greatly help in mitigating such corrosion & erosion-related damages to civil/concrete assets. Epoxies are highly flexible in nature and when applied onto a well-prepared surface, provide outstanding adhesive strength and resistance to corrosion/erosion-related attacks for decades to come.

Epoxy coatings are easy-to-install systems and can be easily repaired in the event of mechanical/unforeseen damages. This helps in saving enormous maintenance & downtime costs for the plant operators in the long run.

Duromar grouting & lining epoxy systems have been extensively used to rebuild and protect several concrete assets exposed to aggressive operating conditions.

The below illustration outlines how a severely damaged Acid Neutralization Trench line at a Thermal Power Plant was rebuilt using Duromar DuroFil epoxy grout and further protected with a novolac rich epoxy liner Duromar DF – 4301.

Several other concrete assets such a Drain Oil Tanks & Cooling Tower Basin tanks that are exposed to moisture-rich environments have been protected with Duromar epoxies and have showcased outstanding results with regards to corrosion protection and asset life enhancement.