Reinforced concrete is concrete in which steel reinforcement (rebar) is embedded to carry tensile forces. Concrete is strong in compression but weak in tension; by adding steel, the concrete takes the compression and the steel takes the tension. This combination forms the basis of virtually all modern structures.
Application
Reinforced concrete is used for foundations, floors, columns, beams, walls and entire load-bearing structures. Wherever bending occurs, such as in a floor slab or a beam, tensile stresses develop on one side; that is exactly where the rebar is placed. In a floor the reinforcement therefore sits at the bottom in the span and at the top over the supports. The correct position and cover of the reinforcement are essential for strength and durability.
Characteristics
The interaction between concrete and steel relies on three properties: a good bond between the two materials, a nearly equal coefficient of thermal expansion, and the protection the alkaline concrete gives the steel against corrosion. For this reason the reinforcement must have sufficient concrete cover. Besides ordinary reinforced concrete there is also prestressed concrete, in which the steel is tensioned in advance to limit cracking.
Related terms
- concrete
- concrete floor
- rebar
- reinforcement
- steel
- foundation
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