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Most people are familiar with reinforcing steel, commonly called "rebar". It is used in bridges, buildings, skyscrapers, homes, warehouses, and foundations to increase the strength of a concrete structure.

Rebar is used in concrete to provide additional strength, as concrete is weak in tension, while steel is strong in both tension and compression. Steel and concrete have similar coefficients of thermal expansion, so a concrete structural member reinforced with steel will experience minimal stress as the temperature changes.

Steel is the product of choice thanks to specific advantages over other materials:

• Ability to be bent – Reinforcing steel can be bent after being manufactured. This simplifies the construction and provides for rapid delivery of fabricated materials.

• Robustness – Reinforcing steel is robust and able to withstand rigors of construction.

• Ability to be recycled – Reinforcing steel is able to be readily recycled at the end of the structure design life.

• Compatibility with concrete – Reinforcing steel does not need to be tied directly to the formwork and does not float in concrete.

• Availability – Reinforcing steel is available in every region of the country. Due to the number and distribution of plants, the United States Green Building Council's Leadership in Energy and Design (LEED®) program and other sustainability credits are available.

 

Steel is ideal for reinforced concrete due to some unique factors:

Elastic properties, Elongation under load, Uniform properties in 3D, Fatigue, Bond development, Yield, Thermal properties, Strength retention, Joining 

 

Rebar Markings

There are a number of ways to identify reinforcing bar (rebar) from the production mill to the fabrication shop to the jobsite. This documentation and marking system helps provide a wealth of useful information about the manufacturing and composition of each bar of reinforcing steel.

Each Individual Reinforcing Bar is Manufactured with a Series of Individual Markings:

• The first letter or symbol identifies the producing mill.

• The next marking is the bar size.*

• The third marking symbol designates the type of reinforcing steel — usually either "S" for carbon-steel (ASTM A615) or "W" for low-alloy steel (ASTM A706).

• Finally, there will be a grade marking (60, 75, 80, 100, 120) or by the addition of one line (60) or two lines (75), three lines (80, 100), or four lines (120) that must be at least five deformations long.

American Society for Testing and Materials (ASTM) Bar Marking Sequence