Steel is the most widely used material in the construction field. Being an alloy of Iron, Carbon, it is known for its high tensile strength and low cost. Before the inclusion of steel, concrete was solely used for building structures but the catch was that concrete could only deal with the compressive strength of the structure and couldn’t deal with the tensile strength. This situation was quite a challenge to overcome until the introduction of reinforcement.
The Rise of Reinforcement
When the concept of Reinforcement was introduced, it changed the phase of construction. Reinforcement resulted in higher tensile strength which the concrete was unable to deal with. The primary component used for reinforcement was Steel particularly TMT reinforced bars, because of its various properties like strength, ductility, durability.
Importance of Thermal Expansion
Thermal expansion is the process in which the material expands under temperature changes. Another important property for materials is the coefficient of thermal expansion. It describes how the shape of metal changes with change in temperature. Steel is the best reinforcement to concrete as both of steel and concrete have similar coefficient of expansion. If their coefficients are different, one will expand more than the other under the heat and thus the mixture will break easily.
The Right Reinforcement
Different types of steel reinforced bars were used as reinforcements for concrete. Mild steel, HYSD steel reinforced bars were some of them, but none of those provided the required strength needed for the structure. This challenge was solved with the introduction of Thermo- Mechanically Treated (TMT) reinforced bar. TMT reinforced bars were prefered because of the excellent tensile strength and ductility it offered.
TMT is the process in which the reinforced steel is produced. The TMT process results in a reinforced bar with an hardened “martensite” outer layer and soft ferrite pearlite core. TMT reinforced bars comes in different grades namely Fe 415, Fe 500 Fe 550, Fe 600.
Grades always matter
The grades of TMT reinforced steel bars are not just numbers, each represents the maximum yield strength for the reinforced bar which means each grade is important for the type of construction design. Tensile strength for higher grade TMT reinforced steel bars is achieved at the cost of compromising ductility, which makes those reinforced bars brittle, which is why they must be used only if the engineer specifies them.