Why reinforcement use in concrete? | Why steel use in Construction?
Why Steel used in Concrete?
Reinforced cement concrete is the one in which steel bars are embedded into the concrete to resist stresses coming over it. Concrete is very weak against tensile stresses and is strong against compressive stresses. The reinforced steel bars are used to bear tensile, shear, and to some extent compressive stresses which a Plain cement concrete is unable to bear.
There are three important types of stress:
- Tension, and
Steel is used for reinforcement because it forms strong bond with concrete and expands and shrinks at similar rate due to temperature variations. Also, because steel is capable of bearing all three forces.
These are the main reasons why reinforcement use in concrete:
- Concrete is brittle in nature while steel is an elastic and highly ductile material which avoids any sudden failure.
- Concrete cannot withstand tension and shear forces due its brittle nature and thus steel is used.
- Reinforced steel concrete takes up less space as compared with PCC.
- Steel and concrete both have very similar properties which enhances each other’s strength.
- Steel and concrete undergo almost similar strain
- Steel is cheap, easy to install and easily available
- Steel reflects same Modulus of Rigidity for both tension and compression.
- Steel can be recycled and thus saving up a lot of money.
- Thermal Expansion Coefficient of both the materials is same and thus helping them form a strong bond.
- Although, Bamboo and concrete also have same coefficient of thermal expansion, steel is yet considered better because it lasts for more than 100 years whilst bamboo lasts only for 20 years.
While steel has so many benefits, we cannot entirely build a structure with steel because it even though it is abundant and cheap, it is still very much expensive than concrete. Secondly, if steel comes in direct contact with water or air, the chances of corrosion increase which can be harmful for structure. We also need to take weight of the structure into account as this factor cannot be ignored. If whole structure is made with steel only, the dead load will be drastically increased.