Pultrusion is a continuous, semi automated process for manufacturing composite materials. Continuous fibres or fabrics made of glass or carbon fibres are impregnated with a resin in the impregnation bath. The material is then drawn through a heated die, by a pulling system located near the end of the pultruder. The composite is then cut into lengths with a cut-off saw.

   Pultruded composites are ideal for infrastructure applications, as the composites are produced with a constant cross section. This makes them directly comparable with metal products, as composite channels and I-beams, as well as other standard sections. Structures made from composites can be light, strong and have no corrosion problems.

   The pultrusion process has been used for several decades overseas. However, research to improve understanding of this process is in its infancy.

   Pultruded grating is designed to provide increased strength/stiffness in conjunction with moderate levels of corrosion resistance. The benefits are derived from the pultruding process in which glass fibres are "pulled" through a thermoset resin bath which "wets out" (coats) the glass which then passes through a heated die.

   High pressure and temperatures densify the composite, further impregnating the fibres and eliminating voids. This process offers a higher glass to resin ratio (approximately 65% glass to 35% resin by weight), which translates directly into its superior strength characteristics. Pultruded grating’s production process allows for greater flexibility in panel sizes available.