Structural Strengthening Techniques in Reinforced Concrete Cooling Towers

Natural draft hyperbolic cooling towers at the heart of large thermal power plants are exposed to high humidity, temperature changes, and chemical effects for decades. Under these conditions, crack formation, concrete spalling, and reinforcement corrosion can become inevitable in reinforced concrete structures.

Corrosion and Concrete Damage

Concrete surfaces in cooling towers are damaged especially through the following mechanisms:

- Carbonation: Penetration of atmospheric CO₂ into the concrete, lowering the pH of the concrete and exposing the reinforcement to corrosion risk.

- Chloride Attack: Degradation of concrete by chlorides in cooling water additives.

- Thermal Cycles: Seasonal expansion-contraction cycles creating micro-cracks.

Applied Strengthening Methods

Carbon Fiber Reinforcement (CFRP): High-strength carbon fiber strips are bonded to concrete surfaces with special epoxy resin. It can improve bending and shear capacity by 40–80% without increasing the weight of the structure.

Epoxy Injection: It involves filling existing cracks with high-pressure epoxy resin to restore original structural integrity. Cracks are closed for both waterproofing and structural continuity.

Protective Coating Systems: Elastomeric coatings and penetrant silanes applied to repaired surfaces protect the concrete against water, chloride, and carbonation in the long term.

Concrete Surface Repair: Damaged concrete areas are cut and removed and recreated with special repair mortars. Polymer-added repair mortars provide full compatibility with the original concrete.

HUBYAPI Approach

Before starting each project, we conduct a comprehensive structural condition assessment: carbonation depth measurement, Schmidt hammer test, ultrasonic pulse velocity measurement, and endoscopic inspection. In line with the data obtained, the most suitable strengthening program is prepared specifically for the project.