Steel reinforcement, also known as rebar, is a common material used in construction to provide additional strength and support to concrete structures. Deformed bar refers to rebar that has ridges or deformations on its surface to improve the bond between the steel and the concrete. This helps to prevent slippage and increase the overall strength of the structure. Deformed bar is typically used in applications where high tensile strength is required, such as in beams, columns, and foundations.