Reinforcing steel (commonly called rebar) is steel that is specifically manufactured to be embedded in concrete, enabling the combined material to resist both compressive and tensile forces. Concrete is strong in compression but weak in tension. By adding reinforcing steel, the result is reinforced concrete — a construction material that can handle both types of stress.
Types of reinforcing steel
- Reinforcement bars — round bars with ribs (deformations) for good bond with the concrete. Common diameters are 6, 8, 10, 12, 16, 20 and 25 mm
- Welded mesh — factory-welded grids of steel bars, widely used in slabs and walls
- Stirrups — bent bars that hold the main reinforcement in place and resist shear forces
- Prestressing steel — high-strength steel that is tensioned before or after the concrete is poured
Application
Reinforcing steel is used in virtually all concrete structures:
- Foundations — reinforcement mesh in foundation slabs and beams
- Floor slabs — top and bottom reinforcement in concrete floors
- Columns and walls — vertical bars with stirrups
- Beams — longitudinal reinforcement and stirrups to resist bending and shear
Concrete cover
The reinforcing steel must have adequate concrete cover (typically 20–50 mm depending on exposure class) to protect the steel against corrosion. Insufficient cover leads to concrete spalling and structural degradation.
Related terms
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