Myth: Corrosion Is Good For TMT

You may have come across a dealer coaxing you to buy a corroded TMT bar saying that corrosion implies the bar is made with pure iron and that this in turn testifies the strength and longevity of the bar. However, this is far from the truth.

While rusting might imply the presence of pure iron, it is infact highly detrimental to the durability of the TMT bar. A study published in 2012 in the Time of India states that every year almost 2 lakh crore is lost in infrastructure due to corrosion of steel- A figure that you certainly do not want your building to be part of!

To confirm why corrosion is bad, let us first understand how it works. The cycle of corrosion starts with expansion of the rust surface. Gradually, this leads to an increase in the volume of steel, which in turn exerts pressure on the concrete, causing spalling in the structure. This ultimately leads to disintegration of the entire edifice. So you see, it all starts with a small amount of rust and expands into a more serious problem with passage of time.

Therefore, when buying TMT bars it is important to keep in mind that they have been protected from corrosion by any of the various methods like polymer coating, hot-dip galvanizing etc. A good TMT bar is corrosion-free to ensure the strength of the structure for years to come.