Reinforced concrete is concrete in which reinforcement bars ("rebars"), reinforcement grids, plates or fibers have been incorporated to strengthen the concrete in tension. It was invented by French gardener Joseph Monier in 1849 and patented in 1867. The term Ferro Concrete refers only to concrete that is reinforced with iron or steel. Other materials used to reinforce concrete can be organic and inorganic fibres as well as composites in different forms. Prior to the invention of reinforcement, concrete was strong in compression, but weak in tension. Adding reinforcement crucially increases the strength in tension. The failure strain of concrete in tension is so low that the reinforcement has to hold the cracked sections together.

For a strong, ductile and durable construction the reinforcement needs to have the following properties:

In most cases reinforced concrete uses steel rebars that have been inserted to add strength.