Short Answer:
The difference between mild steel and high-strength deformed bars lies in their strength, surface texture, and application in construction. Mild steel bars have a smooth surface and lower strength, making them suitable for small-scale structures and temporary works. High-strength deformed bars, on the other hand, have ribs or lugs on their surface, providing better bonding with concrete and higher strength, making them ideal for load-bearing structures like beams, columns, and bridges.
Mild steel is more ductile and easy to bend, while high-strength deformed bars offer better tensile strength and durability. Due to their superior load-bearing capacity, deformed bars are commonly used in modern reinforced concrete structures.
Detailed Explanation
Mild Steel Bars
Mild steel bars, also known as plain steel bars, are smooth round bars used in RCC structures where high strength is not required.
Characteristics of Mild Steel Bars:
- Smooth surface with no ribs or deformations.
- Low strength and bonding capacity with concrete.
- Highly ductile and easy to bend.
- Used in small-scale structures, temporary works, and roads.
Disadvantages of Mild Steel Bars:
- Weak bonding with concrete, leading to slippage.
- Less tensile strength compared to deformed bars.
- Not suitable for high-load applications.
High-Strength Deformed Bars
High-strength deformed bars, also called TMT (Thermo-Mechanically Treated) bars, are used in reinforced concrete structures for better strength and stability.
Characteristics of High-Strength Deformed Bars:
- Have ribs or lugs, improving bonding with concrete.
- Provide higher tensile strength and durability.
- Resistant to corrosion and earthquakes.
- Used in bridges, high-rise buildings, and heavy load-bearing structures.
Advantages of High-Strength Deformed Bars:
- Stronger than mild steel bars, reducing material usage.
- High bonding strength, preventing cracks and slippage.
- Withstand heavy loads, earthquakes, and temperature changes.
Conclusion
Mild steel bars are smooth, easy to bend, and used for small structures, while high-strength deformed bars are ribbed, strong, and ideal for load-bearing structures. Deformed bars are preferred in modern RCC structures due to their high strength, durability, and better bonding with concrete.