A500 (or A4) rebar is a type of high-strength ribbed rebar with specific properties and applications in the construction industry. A500 (A4) rebar has a high yield strength (about 500 MPa), which allows it to withstand heavy loads without permanent deformation. The ribs of this type of rebar are in the form of a hex (herringbone) which creates better engagement with the concrete and increases the adhesion between the rebar and the concrete.