Rebar is a steel bar or mesh of steel wires used as a tension device in reinforced concrete and reinforced masonry structures to strengthen and hold the concrete in tension. Rebar's surface is often patterned to form a better bond with the concrete. When added to concrete, the rebar adds strength and flexibility, which concrete alone does not have.
Can be used as a forming stake or connector tie
Ridges help concrete grip the bar
Rusting does not affect performance
Rebar may also be used to hold other steel bars in the correct position to accommodate their loads