GFRP rebar is a non‑metallic concrete reinforcement composed of continuous glass fibers embedded in a thermosetting polymer resin, typically vinyl ester. It provides a guaranteed tensile strength above 600 MPa per ASTM D7957, while being completely immune to chloride‑induced corrosion — the main degradation mechanism for steel rebar in bridges and coastal structures. With a density roughly one‑quarter that of steel, GFRP rebar also simplifies handling and cutting on site. It is now commonly found in bridge decks and marine infrastructure where exposure to de‑icing salts or seawater is unavoidable.
What is GFRP Rebar: Definition & Concrete Use
GFRP (Glass Fiber Reinforced Polymer) rebar is a reinforcing bar designed for concrete construction, made by combining high‑strength glass fibers with a thermosetting polymer matrix that bonds the fibers and shields them from the alkaline pore solution in concrete.
For instance, GFRP rebar is widely used in bridge deck overlays where road salt makes steel reinforcement impractical.
Corrosion Immunity vs. Steel Rebar
Unlike steel rebar, which requires a passive oxide layer to resist rust and is vulnerable to chloride attack once that layer breaks down, GFRP rebar is inherently inert to chlorides and does not corrode. It needs no protective coatings or high concrete cover for corrosion resistance; the only cover required is for bond development and fire protection.
A Standard Strength Reference
Standard GFRP rebar, conforming to ASTM D7957, provides a guaranteed minimum tensile strength above 600 MPa.
For practical applications, see how GFRP reinforcement functions in structural concrete elements.
For deeper technical background, see FRP Properties & Characteristics.