Why is Steel Used for Reinforcing Concrete in Buildings

Concrete has been an important building material ever since Portland cement was invented in 1824. The material is easy to work with and offers flexibility. Concrete is also non-combustible, and it offers good structural strength when compressed. However, concrete cannot be used as the sole material for a structure due to its limitations.

For starters, concrete has low tensile strength when compared to other materials. It is also not the material with the highest strength-to-weight ratio, even with so many advancements in concrete construction and handling we have today.

As a way to get around these limitations, other materials are used to reinforce concrete structures. The most common material used for this purpose is steel; steel pilings to be exact. So, why is steel used for reinforcing concrete in buildings?

tunnel - Steel

Added Tensile Strength

Tensile strength is perhaps the biggest weakness of concrete as a material. When compressed to a certain degree, concrete is rigid and has no flexibility at all. When exposed to the elements and ground movement, that excessive rigidity – and low tensile strength – means concrete is more likely to break under pressure.

The use of steel reinforcement inside concrete helps alleviate some of the excess rigidity. Steel itself is a flexible material, so the combination creates the right balance needed for maximum structural strength.

At the same time, pile cages inside concrete allow the entire structure to flex and move without losing its toughness. The cages are meant to eliminate the brittle nature of concrete and allow cement and other materials to bond together perfectly. In fact, some building projects use unconventional steel cage designs to add more flexibility and allow more structural movement.

There are also reasons why today’s steel pile reinforcement is designed in a certain way. Prefabricated steel cages and pilings have interconnected beams and sections so that the cage – and the individual pile – can bond perfectly with concrete.

Take a look at the steel cages from Heaton Products and you will see that they are designed for maximum bonding. Heaton Products offer a range of steel pile reinforcement in different diameters. All cages are designed for maximum bonding.

Another interesting property of a steel cage is its load-spreading ability. When building a structure on an unstable surface, for example, CFA piles can be used to spread the load across a bigger surface. The end of the pile acts as a root, allowing for deep foundations to be constructed with precision.


It Doesn’t Break

Steel is also a material loved by architects and engineers because of its rigidity. The modulus of rigidity remains the same regardless of whether it is compressed or not. Under tension and compression, steel maintains its strength and even provide more support for the entire structure.

That same property gets amplified when steel is used in a certain way, including in the form of pile cages. Combined with concrete – which relies on compression for its strength – the theoretical rigidity of steel is amplified further.

The same property is seen in bamboo, but steel has an obvious advantage against this material: it is much more durable. While the combination of bamboo and concrete provides a lifespan of around 20 to 30 years, steel and concrete mix extends that lifespan to more than 100 years.

Exposed to the Elements

In extreme temperatures, both steel and concrete have a relatively similar thermal expansion coefficient, which means both materials will expand and contract by the same amount in different weather conditions.

Under extreme heat – such as in the event of a fire – it is the concrete that will lose its integrity first. Steel cages sitting inside a concrete beam or structure will handle the excess load and keep the entire structure standing, allowing the building to remain safe for its occupants.

The same is true for when the weather gets extremely cold. Both materials will contract, but extremely cold weather is more likely to break concrete first before it can affect the steel cages inside concrete structures.


Let’s not forget that steel is a sustainable material. It can be recycled and repurposed thanks to its flexibility as a material. In fact, many of the construction projects we have today are using recycled steel piles and beams instead of new ones.

It is easy to remove impurities in steel, plus you maintain the same strength and properties when recycling the material. In the long run, steel is more sustainable than other building materials used today. It is even more economical to use thanks to its longer lifespan.

There are still more benefits of using steel with concrete that we can explore, but the simple fact is this: steel and concrete are perfect for each other. They are the main materials used in construction projects today and will continue to be the main materials for projects in the future. 

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