This is with reference to the letter of A.K.Sen published in the 3-6-13 issue of SOM. The writer is correct about the corrosive action of chlorine on the reinforced cement concrete used in constructing water reservoirs. Chlorine by itself may have some reaction on the iron rods in RCC, but in the presence of moisture it forms hydrochloric and hypochlorous acids which rapidly attack exposed iron. When the roof of Vijayanagar Central Storage Reservoir collapsed a few years ago, it was noticed that the iron rods when they are corroded by chlorine and moisture expand in size causing the surrounding cement concrete to crack. Soon the strength and integrity of the RCC is compromised and the roof collapses.
MGP has written letters to the authorities that construction of water reservoir roofs is a specialized job and can not be done by any ordinary contractor. It should be entrusted to specialized builders who have the technical knowledge of design and construction of high density concrete roofing capable of withstanding corrosion by chlorine. But our letters have been ignored and the work is given to regular contractors. As a result, the structures do not last long and public money is wasted.
Prof. A. Ramalingam, Mysore Grahakara Parishat