Why is most rebar deformed?

Most rebar is deformed primarily to enhance the bond strength between the rebar and the surrounding concrete. The deformations create mechanical interlocking between the rebar and the concrete, which significantly improves the shear transfer between the two materials. This mechanical bond is crucial for the effective transfer of loads and stresses, ensuring that the rebar can perform its role in reinforcing concrete structures. By providing a better adherence to concrete, deformed rebar helps prevent slippage and increases the overall structural integrity and durability of reinforced concrete elements. This characteristic is vital in applications where tensile strength is essential, as concrete is strong in compression but weak in tension.