Using Deformed Reinforcing Steel Bar

Deformed reinforcing bar is used in a range of residential, commercial and infrastructure applications from concrete slabs to prefabricated beams, columns, cages and precast products. Deformed reinforcing bar complies with all relevant standards. 

Reinforcing steel and bar is also known as reo mesh, rebar, re-bar or reo bar. It is used to strengthen concrete because of its poor tensile strength. The presence of deformed bar is key to help concrete to adhere to a bar’s surface. In most cases around Perth and Western Australia, an engineer is commissioned early on to specify what mesh and bar are required for retaining walls, footings, slabs or suspended slabs. Read on…

Deformed bar is a Class N (normal ductility) reinforcing bar used in a range of applications from reinforced concrete slabs to prefabricated beams, columns, cages and precast products. Also known as rebar, deformed bar complies with AS/NZS 4671 : 2001 Steel reinforcing materials and is available in 500 MPa from 10 mm – 40 mm bar diameters. Always consult with an engineer before choosing the bar suited for your application. Find out more

The deformed Reinforcing Steel Bar is supplied in length of 9m or 12 m as common sizes. The steel bar diameter applied is different and accordingly the weight varies.

A steel reinforcing bar which is manufactured with surface deformations to provide a locking anchorage with surrounding concrete. Reinforced concrete is a material that is very strong in compression, but virtually without strength in tension. To compensate for this imbalance in a concrete slab’s behavior, reinforcement bar (also known as rebar) is cast into it to carry the tensile loads. Deformed Bar was previously called Y-Bar eg: Y12, Y16 but through product improvements the tempcore strength was increased (now 500Mpa) and is now denoted as N-Bar. Refer here.

In reinforced concrete design it is generally assumed that the strain in the steel reinforcement is equal to the strain in the concrete immediately surrounding it. This is substantially true in zones of compression but, in the parts subject to tension, the working stress in the steel is usually high enough for the strain to be more than the surrounding concrete can withstand without cracking. The size of the cracks formed in this way and their spacing along the reinforcement depends primarily on the bond but is also affected by the strain in the steel, the tensile strength of the concrete and its modulus of elasticity. 

Reinforced concrete was designed on the principle that steel and concrete act together in resisting force. Concrete is strong in compression but weak in tension. The tensile strength is generally rated about 10 percent of the compression strength. For this reason, concrete works well for columns and posts that are compression members in a structure. But, when it is used for tension members, such as beams, girders, foundation walls, or floors, concrete must be reinforced to attain the necessary tension strength.

Steel is the best material for reinforcing concrete because the properties of expansion for both steel and concrete are considered to be approximate] y the same; that is, under normal conditions, they will expand and contract at an almost equal rate.

Another reason steel works well as a reinforcement for concrete is because it bonds well with concrete. This bond strength is proportional to the contact surface of the steel to the concrete. In other words, the greater the surface of steel exposed to the adherence of concrete, the stronger the bond. A deformed reinforcing bar adheres better than a plain, round, or square one because it has a greater bearing surface. In fact, when plain bars of the same diameter are used instead of deformed bars, approximately 40 percent more bars must be used.

The rougher the surface of the steel, the better it adheres to concrete. Thus steel with a light, firm layer of rust is superior to clean steel; however, steel with loose or scaly rust is inferior. Loose or scaly rust can be removed from the steel by rubbing the steel with burlap or similar material. This action leaves only the firm layer of rust on the steel to adhere to the concrete.

 

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