rebars

Rebars, short for reinforcing bars, are steel bars embedded in concrete to carry tensile forces, since concrete is strong in compression but weak in tension. Most rebars are ribbed or deformed to improve mechanical bonding with surrounding concrete, though plain bars are used in certain applications. They are manufactured in a range of diameters and lengths and may be plain or reinforced with surface deformations. Protective coatings such as epoxy, galvanizing, or stainless steel are used in harsh environments to resist corrosion.

Standards govern their properties and sizing. In North America, common specifications include ASTM A615/A615M and A706; in Europe, EN standards cover high-strength reinforcing bars; many countries also follow national standards, such as IS 1786 in India. Bars are designated by yield strength; standard grades typically run around 400 MPa, with higher-strength bars at 500–600 MPa used for seismic design or high-load applications.

Rebars are typically produced by hot-rolling and come in fixed lengths (commonly about 12 meters) that are cut or bent to fit a structure. On construction sites, bars are tied or welded in place and may require development lengths or lap splices to transfer tension safely. Proper anchorage and cover are essential to ensure bond with concrete and to protect against corrosion.

Applications include reinforced concrete slabs, beams, columns, walls, and foundations. In aggressive or marine environments, corrosion protection becomes critical, leading to the use of epoxy-coated, galvanized, stainless, or composite (FRP) rebar. FRP rebar offers corrosion resistance but has different mechanical properties and cost considerations.