Reinforced concrete, also called ferroconcrete, 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. In terms of volume used annually, it is one of the most common engineering materials. In corrosion engineering terms, when designed correctly, the alkalinity of the concrete protects the steel rebar from corrosion.

The Coignet Stone Company Building is a historical structure in the Gowanus neighborhood of Brooklyn in New York City, at the intersection of Third Street and Third Avenue. Designed by architects William Field and Son and constructed between 1872 and 1873, it is the city's oldest remaining concrete building. The Coignet Building is the last remaining structure of a five-acre concrete factory complex built for the Coignet Agglomerate Company along the Gowanus Canal.