Reinforced concrete (RC), also called reinforced cement concrete (RCC), is a composite material in which concrete’s relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having higher tensile strength or ductility. The reinforcement is usually, though not necessarily, steel bars (rebar) and is usually embedded passively in the concrete before the concrete sets. However, post-tensioning is also employed as a technique to reinforce the concrete. Worldwide, in volume terms, it is an absolutely key engineering material. In corrosion engineering terms, when designed correctly, the alkalinity of the concrete protects the steel rebar from corrosion.