Steel, the most versatile, strong and durable material for reinforcing concrete for constructing buildings. No doubt, it is the only material so far that has proven successful to bond with concrete for reinforcement. The main reasons are, One, steel has high tensile strength and is able to withstand the tensile forces in a structure which the concrete lacks. Second, the thermal coefficient of expansion of steel is similar to that of concrete.
Nowadays TMT steels are commonly used in constructions. What is TMT? Why is it used than other types of steel? Well, before TMT was introduced Mild Steel (MS) bars, Cold Twisted Deformed (CTD) bars were primarily used with concrete for constructing buildings. Those steel were graded Fe 250 but their low strength was a problem for buildings requiring more strength.
The TMT in TMT Bars stand for Thermo-Mechanically Treated, it is a process of rapidly cooling down bars in the molten state. This cooling down process is either done spraying water at regular intervals. This regular interval will further define the characteristics of the bars. This interval of quenching of bars will give rise to different grades of TMT bars in fact. The goal here is to have a solid and hard outer surface with a pliable inner core. This outer shell is coated with a protective film, making them resistant to corrosion and rust, making them apt for constructing sensitive structures such as high rise residential buildings and bridges in humid areas. TMT bars and different Steel Grades.