The corrosion concerns
Despite the enormous amount of research into corrosion in the Construction Industry losses up to £546m p.a. occur due to corrosion of metals (source: emerald insights paper)
In India, most of our cities and coastal areas are highlight prone to corrosion owing to the level of moisture and increasing level of dust and pollutants in the air.
Corrosion causes the metal to degrade and weaken thereby raising high concerns regarding the safety, durability and the strength of the construction. Metals used in construction are zinc, steel, iron andaluminum. The oxidation process that occurs between iron, steel and oxygen is one of the most critical corrosion problems faced by the industry, commonly termed as ‘rust’.All steel and iron structures are prone to corrosion and need a systematic method to prevent that from happening.
Anode at the rescue
One most proven and established method of mitigating corrosion risk to enhance the strength and life of reinforcement structures is using Sacrificial Anodes.It is so termed because one of the metals is sacrificed to protect the reinforcement.
To demonstrate the benefits of this method, we tried an experiment. We removed a part of an overhanging eave, tied an anode to it and covered it with a plaster.
After 2 years we checked the results using a herself potentiometer. The readings of the anode protected area and the readings of another spot just 4 meters away, were the proof of the potential benefits of a sacrificial anode. We then extracted the entire structure and the volume of the anode protected area was found to be intact, whereas corroded area appeared to be swollen and the volume was higher.This implies that ANODE is effective in safeguarding the properties of the structure and protecting from damage.
To simplify this, consider the magic of anode and cathode. In the Sacrificial Anode Mechanism, the electric potential difference between two metals one of them being zinc, is used to create free flowing ions and the more active metal begins to corrode, thereby loosing electrons. Anode has an alkali activate mortar covering. The electrons then travel through the structure thereby causing a chemical reaction that helps to prevent corrosion of the structure.
Sacrificial anode systems have the advantage of being simple and easy to install, requires no external electric power source and com across as a cost-effective solution as compared to other anti-corrosion techniques. Anodes work very well in high aggressive weather conditions for industries, chemical industries, cooling towers, chimneys, bridges etc.
This method needs to be widely understood and adapted to safeguard structures and increase the longevity of structures in our country.