Concrete is a building material used in structures all over the world. When poured and fully set, concrete is relatively durable, yet its weak tensile strength can result in cracks when the slab expands and contracts. To compensate for fluctuations in temperature, ground water, and air quality, reinforcing steel is placed within the concrete. Known as rebar, these carbon steel rods help distribute structural loads and reinforce hardened concrete.

Several reinforced concrete slab columns, image by Marcus Mitanis

Steel is an ideal reinforcing material, as concrete and steel expand and contract at about the same rate. Separation between the two is kept to a minimum as a result, which prevents cracks from forming. Rebar rods can be tied together to create a grid or cage of steel mesh, which is often installed in larger building projects. Though rebar is mostly found in load-bearing concrete structures, it can be used in brick and mortar projects as well. This is known as reinforced masonry.

Rebar poking out of a concrete slab, image by Marcus Mitanis

Rebar installation is an intricate process. Its susceptibility to rust must be considered carefully, so rebar has to be installed at the correct depth to avoid contact with external water and moisture. In locations where water seepage through the concrete may be an issue, polymer coated rebar is a popular rust-resistant solution. 

Rebar cages awaiting placement, image by Marcus Mitanis

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