Investigations were conducted to assess and determine root cause of the ongoing concrete deterioration of the cooling tower. The beams, columns, wall panels of end walls, roof slab, bund wall, and louvers, were visually exhibiting severe concrete deterioration in many areas across the entire structure. In some areas, the concrete deterioration was very advanced and posing serious threat to integrity of the structure. Chloride had penetrated to full depth of the concrete cover in concentrations significantly higher than threshold level. Electrochemical measurements showed that the reinforcing steel was actively corroding under the sound concrete in >50% areas of the entire structure.

The visual condition of the exposed steel and the survey results concluded that the deterioration of concrete resulted due to chloride-induced corrosion of the reinforcing steel. There was no risk of carbonation-induced corrosion of steel and sulfate attack on concrete. Patch repair and cathodic protection (CP) repair method was recommended to arrest the ongoing corrosion of the steel reinforcement. The CP system design, installation, and initial commissioning and monitoring results are also described and discussed.