Why is Steel Used as Reinforcement in Concrete

Concrete is one of the most popular building materials – and for good reason. It is cheap, moldable, and easy to make from ingredients that aren’t difficult to find. Additionally, it is strong under compressive forces – meaning that it can resist weight piled on top of it.

However as great as concrete is, it does have several weaknesses. Chief among these is the fact that it is actually rather weak against tension and shear forces – to the point where it could even be considered brittle.

That is the reason why concrete needs to be reinforced to act as a reliable building material. And the way that is done is by using steel.

How Steel Helps Reinforced Concrete

As mentioned, plain concrete is strong against compression but weak against tension and shear. The way steel can fix that and reinforce the concrete is by placing steel rods, mesh, or wires into the concrete so that it sets and bonds with them.

How Steel Helps Reinforced Concrete

That effectively will create a new composite material – referred to as reinforced concrete. The concrete in the material allows it to resist compression, while the steel in it resists bending and stretching from tension and shear.

Simply put, steel helps the concrete to overcome its weaknesses and make it into a far stronger building material.

Why Steel is Preferred to Reinforce Concrete

Although there are several alternative materials that can be used to reinforce concrete, steel is the most popular – and for good reason. The fact of the matter is that its properties make it the perfect choice.

The main reasons why steel is preferred are:

  • Bonds well with concrete:Steel forms a strong bond with concrete that lets it act as a new composite material instead of just the combination of two different materials. Its strong bond is the reason both materials can act together to resist forces.
  • Similar coefficient of thermal expansion:Different materials expand at different rates when heated (or shrink when cooled). Because steel and concrete both have similar coefficients of thermal expansion, they expand and shrink at similar rates which let them retain their strong bond at any temperature.
  • Highly ductile:The fact that steel is highly ductile is what allows it to bend without breaking. This property is useful in material to reinforce concrete as it means that steel can be bent into the ideal shape to support the concrete that is poured.
  • Easy to weld:Another property that lets steel reinforce concrete effectively is that it is easy to weld. Steel bars can be welded into unique shapes and structures, or to extend the span length.
  • Cheap and widely-available:As a material, steel is both cheap and widely available. As such using it to reinforce concrete won’t put too much of a strain on the budget for construction projects, nor will it be difficult to source.
  • Recyclable:The steel used to reinforce concrete can be recycled easily if the building is ever deconstructed. It simply needs to be melted down and reformed into new steel bars for the next construction project.

Taking into account all these properties, it should be easy to see why steel is preferred over and above any other material to reinforce concrete. Suffice to say it fits the role like a glove.


Steel and concrete really do have an inseparable relationship – whether it is steel bars to reinforce concrete, or a steel deck to give it support. The role that steel plays in reinforcing concrete is essential in construction, and none of the alternative materials are able to hold a candle to it.