Why concrete is reinforced with steel

Many years ago, buildings were primarily built with stone. But stone is heavy, must be transported long distances, and must be cut to size from a larger piece of stone. With the invention of concrete in 1849 came the ability to create building blocks of different sizes and shapes at the building location rather than hauling stone to the site.

Concrete is a pretty impressive material. With the right mix of water, cement, and both fine and course aggregates (sand, gravel, glass, crushed rock, etc.), we can make sidewalks, buildings, bridges, and much more. When it dries, concrete becomes incredibly strong and durable, especially under compression.

There are, however, some drawbacks to concrete. One of them is that it’s much weaker under tension than it is under compression, which means it snaps if bent or stretched. The answer to that problem is reinforcing concrete with steel.

The steel bars used in concrete are most commonly known as rebar, which is short for reinforcing bar. They have ridges around the outside to help anchor them in the concrete, which is poured around them and allowed to harden. Once hardened, it’s a new material called reinforced concrete that is durable under both compression and tension because of the added strength of the steel bars.

Why steel and not some other material? When hot or cold, steel expands and contracts at a similar rate to concrete, which makes it an ideal material for reinforcing concrete. While steel is still by far the most popular option, there are some reinforced concretes made using plastic or other materials to add strength.

Reinforced concrete can be used in buildings, bridges, slabs of commercial buildings or homes, and really any place that concrete is used. While there are significant advantages in using steel to reinforce concrete, there are some potential risks as well. Rebar can corrode over time, which may result in staining on the concrete surface or weakening of the concrete’s strength.

Large concrete structures, such as parking garages, should be regularly inspected for any signs of concrete damage or steel corrosion. But with regular inspection and maintenance, parking garages and other structures built with reinforced concrete are built to last thanks to the combination of concrete and steel.