What kind of bars were used before TMT bars?

 Welcome to " thecivilengineer18.com ",

What are TMT bars?

Thermo-Mechanically Treated, or TMT, bars are a kind of reinforced steel bar that are widely used in building. By using a particular manufacturing procedure, the TMT process improves the steel's qualities and makes it more appropriate for use as reinforcement in concrete.

Below is a summary of the advantages of the TMT bar production process:

• Heating: In a furnace, the steel billets are brought to a high temperature.
• Rolling: To form the hot steel into bars, it is subsequently run through a number of rollers.
• Quenching: Using water or a specific cooling agent, the hot bars are quickly cooled after shaping. The outside layer of the bars gets hardened by this quick cooling process, often known as "quenching," while the inner core stays comparatively pliable and soft.
• Tempering: To reduce internal tensions and increase toughness, the bars are then heated under regulated conditions.

What before TMT Bars?

Prior to the widespread use of TMT (Thermo-Mechanically Treated) bars, several kind of reinforcing bars were employed in building. The principal ones consist of:

1. Mild Steel Bars
2. High Tensile steel Bars
3. Deformed Bars

Mild steel bars : 

    Sometimes referred to as MS bars, are composed of low-carbon steel. Because they were ductile and easy to bend, they were utilized extensively in construction. In contrast to TMT bars, they have a lower tensile strength.

Applications: 

1. Residential Construction: Beams, columns, and slabs are just a few of the structural components made of mild steel bars that are frequently used in residential constructions.
2. Non-Critical Structures: They are appropriate for constructions like some types of pavements, foundations, and other less demanding applications where extreme durability and strength are not as important.
3. Reinforcement: They are utilized in concrete as reinforcement to increase the structure's overall flexibility and tensile strength.

Restrictions of Mild Steel Bars:

1. Reduced Strength :The tensile strength of mild steel bars is lower than that of TMT bars, which may prevent them from being used in high-stress situations.
2. Corrosion :Compared to TMT bars, mild steel is more prone to corrosion, which, if improperly protected, might eventually result in decreased durability.

High Tensile Steel Bars 

    These bars were utilized in situations requiring greater strength since they had a higher tensile strength than mild steel bars. To get the necessary strength, alloy and carbon steel are frequently combined in their construction.

Applications: 

1. High-Stress constructions: Bridges, tall buildings, and heavy-load foundations are a few examples of applications: Constructions that use HT bars to withstand high tensile strains.
2. Reinforced Concrete: They are frequently utilized to increase the load-bearing capacity and structural strength of reinforced concrete.
3. Industrial Applications: When high strength and durability are essential, HT bars are appropriate for use in industrial machinery and structures.

Restrictions of High tensile steel bars

1. Weldability: Due of their high tensile strength, they may be more challenging to weld, needing certain methods and tools.
2. Cost: The cost of HT bars is higher than that of mild steel bars, which could have an impact on the project's total budget.

Deformed Bars

    The ribs or deformations on the surface of these bars aid in strengthening the bond with the concrete. Although they weren't as strong or long-lasting as TMT bars, they were still in use at the time.

Uses:

1. Reinforced Concrete Structures: Beams, columns, slabs, and foundations are examples of reinforced concrete elements that frequently use deformed bars. They give the necessary tensile strength to offset the compressive stresses that concrete can't manage on its own.
2. High-Stress regions: Deformed bars are employed in high-stress regions, like bridges, high-rise buildings, and large industrial constructions, because of their strength and bond-enhancing qualities.
3. Seismic Design: To increase a structure's ductility and energy absorption capacity in seismically active areas, deformed bars are used into seismic-resistant designs.

Restrictions of Deformed bars

1. Corrosion: If deformed bars are exposed to severe environmental conditions or are not well protected, they may succumb to corrosion similar to other forms of steel reinforcement.
2. Handling and Placing: Because of their deformations, the bars can be more difficult to handle and precisely place, necessitating close attention throughout assembly.
3.     Because TMT bars are stronger, more resilient to corrosion, and longer-lasting than these previous forms of reinforcement, they have mostly supplanted them. They are created by heating the steel and quickly cooling it, giving it a hard outside and a softer interior, resulting in a material with great strength and ductility.

Main Advantages of TMT Bars:

High Strength

    The TMT procedure increases the bars' tensile strength, increasing their capacity to bear strain and severe loads.

Ductility 

    TMT bars can bend without breaking because their core is still flexible and ductile. This is crucial for building techniques that call for bending and shaping reinforcement bars.

Corrosion Resistance

    TMT bars' tough outer surface offers superior corrosion resistance, increasing the life of structures.

Bonding with Concrete 

    TMT bars' distorted surface strengthens their bond with concrete, resulting in a structure that is more robust and long-lasting.

TMT bars are generally chosen in contemporary construction because of their exceptional mechanical qualities and robustness, which enhance the longevity and safety of buildings.

Hope this answer helps you, Share to those who need this, Happy Learning!