Concrete101: Steel

Rod busting, as it is affectionately known in the concrete industry, is a term used to describe steel work. Steel work in concrete is crucial to defining the true strength of concrete. Heavy pours like footers, retaining walls and slabs with heavy loads are all concrete pours that require the use of steel grids and mats to add to the strength of concrete. Concrete that exceed the thickness of four inches can easily break under stress without the use of steel.

Rebar

Reinforcing steel bars-AKA Rebar-are used on a wide variety of concrete pours. They are bent into shape and tied tighter to create a solid structure inside of the concrete. As the wet concrete is poured around the rebar, it bonds with the rough exterior of the rebar and creates a complete bond that fortifies the concrete, giving it the tensile strength that is needed for support of the loads and forces that work against the concrete.

While rebar comes in a wide variety of sizes and strengths, it is commonly referred to by number. These numbers (#3, #5, #8, etc.) represent the actual diameter of the steel. For instance, #5 rebar which is the most commonly used number for footers, slabs and other structural concrete is 5/8" in diameter. The number refers to how many 1/8ths in diameter the rebar is. The print will always tell you the diameter of the steel needed for each particular job.

The strength of the rebar is also determined by a number. Schedule 40 is the most common form of rebar strength and it is used in mostly residential and light commercial applications. Schedule 60 is harder steel that is typically used in industrial applications.

Rebar also comes with various exterior textures. The most common rebar is called deformed rolled. As it is stamped out from the factory furnaces, the exterior is deformed with raised ridges that act to better bond with concrete. Non-deformed rebar is smooth and works best in columns and other tight pours that requires the concrete to slip past the steel easily.

Rod Busting

Working with steel may seem like it requires torches for cutting and huge machines to bend it. In fact, rebar can easily be cut and bent using a rebar cutter/bender. This simple device uses leverage and manpower to bend and cut the steel to its finished shape. Never use heat to bend or cut steel. It weakens the steel to a point where it can become brittle and shear where it is needed most. Learn the secrets of concrete work and other home improvement projects at Construct101.