Rebar is a type of steel that is used to reinforce construction structures. The name itself actually indicates the metal's purpose, as rebar stands for "reinforcing bar." The most common use of rebar is when it is used to build the reinforcing structure that concrete is poured on top of. The steel improves the strength of the concrete.
The first thing most people notice when they pick up a piece of rebar is that ridges run up and down the length of the metal bar. These ridges are designed to help the bar secure itself into the concrete better. When the concrete is poured it flows under and around the ridges so that the bar in essence grips on to the concrete when it dries. This forms a much more solid reinforcement than a smooth bar would provide.
Concrete is strong in many ways. However, it does not have great tensile strength. Steel, on the other hand does have a great deal of tensile strength. Rebar placed into concrete helps to increase the overall strength of the structure, because the tensile strength of the rebar helps to hold the structure together where concrete alone would not be strong enough.
Rebar is made from carbon steel. This is the most common type of steel manufactured. Steel is made using many different elements to create alloys, but in carbon steel, no other alloy material is added to the material beyond the carbon. Carbon steel is very strong and may contain as much as 2 percent carbon in the material.
Rebar can be worked with in a number of different ways. It can be heated and bent, a technique often used to create a hook at the end of the bar to reinforce an anchor position. The material is also suitable for welding. In situations where even the small reduction in strength that might occur from welding is unacceptable, rebar is usually wired to other bars instead.