Rebar is a structural member that is cast into concrete and masonry to provide strength and reinforcement. A reinforcing bar, rebar is used to compensate for the relatively weak tensile strength of these popular building materials.
Types of Rebar
There are two basic types of rebar: steel and fiberglass. Steel rebar is usually made of carbon steel and features ridges for better anchoring. Fiberglass rebar made of fiber-reinforced polymer (FRP), a composite material that consists of a polymer matrix reinforced with glass fibers. In addition to materials of construction, rebar carries specification for sizes and grades, placement, and applications. Steel rebar is used to extend the lifetime of concrete structures such as highway bridge decks and parking garages. They are also used to strengthen and support outdoor walls made of concrete blocks and masonry. Stainless steel rebar is suitable for corrosive environments and marine applications.
Rebar sticks that are made of austenitic stainless steel are sometimes supplied as non-magnetic materials and may be used in medical, military, and scientific applications. Stainless steel reinforcing bars superior strength, ductility and toughness, and are recommended for earthquake zones. Fiberglass rebar is sometimes used instead of stainless steel rebar because of its tensile strength, corrosion resistance, and relatively low cost. Epoxy-coated steel rebar is also available, but this building and construction product is susceptible to oxidation when exposed to chlorides. Typically, this type of rusting occurs on highway bridge decks where road salts are used, building sites with aggressive chemicals, and locations where salt-contaminated aggregates are part of the concrete. FRP rebar is also suitable for applications that require low electrical conductivity or electromagnetic neutrality. Concrete reinforcing bar or rebar is available in grades and specifications that differ in terms of yield strength, ultimate tensile strength (UTS), chemical composition, and percentage of elongation. Typically, the grade designation is equal to the minimum yield strength of the rebar in kilo-pounds per square inch (ksi). For example, Grade 60 rebar has a minimum yield strength of 60 ksi. Other grades include Grade 40 rebar and Grade 75 rebar. Common specifications are ASTM A 615 for carbon steel rebar, ASTM A 706 for seismic rebar, ASTM A 955 for stainless steel rebar, and ASTM A 996 for rail steel rebar and axle steel rebar.