Development of a System for the Production of Disposable Carbon Fiber Formworks

This article presents a new method for the production of disposable carbon fiber formworks for the casting of reinforced concrete columns. The desired three-dimensional object can be made by the robotic hot wire cutting of polystyrene, thus generating the shape around which the carbon fiber is deposited. The manufacturing technique is the so-called filament winding, where the polystyrene shape—obtained through hotwire cutting—is wrapped in fiber tape and then undergoes a curing process, which returns the carbon geometry in solid form. At the end of the process, the final piece of carbon is obtained by dissolving the positive polystyrene mold with a solvent. This gives rise to a production method capable of creating geometries that cannot be achieved by other means. The choice of creating disposable fiber formworks for concrete castings has considerable advantages: the possibility of creating structural elements with complex geometries that cannot be obtained by means of traditional formworks or other materials; saving of time in the casting phase and the advantage of not having the de-casting phase; facilitating the positioning of formworks and other structural elements thanks to the reduced weight of the material; the possibility of having always different geometries and a finish with a high aesthetic value and functional performance. The combination of concrete and carbon fibers offers above all considerable advantages from the structural point of view. The formwork not only has the function of giving shape to the finished element but also becomes a collaborator for static purposes. If used for pillars, the carbon fiber formwork has the function of a hoop, which makes it possible to obtain columns with the same static capacity but with lower sections and the elimination of the transversal reinforcement.