Savcor India Now Offers Protection of Corroding Reinforced Concrete Structure in the Pulp and Paper Industry

Chloride extraction or desalination is a proven technology for the protection of reinforced concrete structural members of pulp mills in the paper industry. Pulp mills are large industrial facilities that convert timber, wood chips and other wood products into wood pulp that is used to produce paper, cardboard or other paper related products.

Typical corrosion of steel rebars in a pulp mill

The manufacturing process uses a substantial amount of chlorine to bleach the wood pulp to produce white paper. Use of chlorine in the pulping process causes the formation of chloride ions that diffuse into the concrete, resulting in pitting corrosion of the reinforcing steel embedded in the reinforced concrete members. The mechanism is electrochemical in nature and this is potentially hazardous to the structural integrity of the members. The view of plant managers is that conventional methods of patch repairs adopted for the restoration of structural members suffering from chloride induced corrosion damage are short lived. Those repairs are not sustainable in the long-term and recurrence of distress is not uncommon, resulting in a loss of production time due to frequent shutdowns as well as compromising on the safety of the structure.

In order to provide a permanent solution, Savcor offers an electrochemical repair technology, which addresses the root cause, chloride ions. This comprises two technologies.

The first is Desalination which is also known as electrochemical chloride extraction (ECE) from the concrete. The ECE process removes chloride ions from contaminated concrete. The concentration of chloride ions in the vicinity of steel reinforcement is reduced to a level below the threshold at which corrosion cannot occur. Hydroxyl ions are also generated at the reinforcement, which allows the passive oxide layer on the steel to be reformed after treatment. Once the process is completed, the structure is covered with a barrier coat to prevent further ingress of chloride ions.

The second electrochemical repair technology offered by Savcor is Impressed Current Cathodic Protection (ICCP).

Several electrochemical techniques have been developed to treat chloride contaminate concrete. The oldest and most effective of these techniques is ICCP.

It involves the use of a small direct current passed from an anode, usually placed on the concrete surface, through to the reinforcing steel. Sufficient current is used to stop an anodic reaction at the steel and to render the steel cathodic where corrosion cannot occur. Savcor provides both these technologies in India on a 'turnkey' basis.