The fibreglass reinforcement (also known as glass-fibre reinforced plastic or composite rebar, mesh) is steadily replacing conventional steel rebar in construction across the world. FRP rebar is made out of a mix of ultra-strong glass or basalt fibres and a connecting resin, resulting in a construction grade rebar with prevailing benefits over steel. Synthetic resins are used as a binding agent for fibres, protecting the fibres from mechanical effects and from the harmful affects of the environment during manufacturing of the product and its operation.
Fibreglass reinforcement manufacturing process consists of several main stages. First, fibreglass in the form of continuous strands is impregnated in a special container with a polymer resin, which contains a curing composition, as a result of which the so-called roving is obtained.
When the fibreglass is completely soaked, the roving is fed into the forming die to obtain a bar of a given diameter. Without waiting for the bar to harden, the source material is pulled through the polymerization chamber and heated to a certain temperature. Finally, the stock is wound and secured to create a ribbed surface. The bar with the rib woven onto it, enters the drying chamber, where the resin is polymerized. After polymerization, the finished reinforcement enters the cooling unit and then the rebar is cut into sections of a predetermined length or wound into coils.
There are 2 main components used in the production: the armoring material (roving) and binding mixture (epoxy or polyester resin). The ratio of these components is about 80/20. In the finished reinforcement, the roving perceives mechanical loads, and the resin acts as a matrix, evenly distributing the load along the entire length of the bar and protecting the reinforcement from the external factors.
The production line must be set up in a warehouse with specific characteristics. Its length shall be at least 50 meters (recommended length is 70 meters), ceiling height shall be at least 2.5 meters (recommended height is at least 3 meters), the height difference in the equipment location area shall be not more than 4-5 cm. Ventilation with air outflow must be of at least 200-250 litres per minute. Indoor air temperature shall be at least 16-18 °С.