This research deals with unreinforced and fiber-reinforced Polymer Concrete (PC). Polymer Concrete is usually composed of natural aggregates such as silica sand, binded together with a thermoset resin, such as unsaturated polyester. In this paper it is reported the use of a direct method to calculate two size independent fracture parameters, the critical stress intensity factor, K Ic, and the critical crack tip opening displacement, CTODC, from experimental results of two different size single edge notched beams, 10 and 20 mm, subjected to three point bending under quasi-static loading condition. This method is called the Two Parameter Fracture Model (TPFM). Also the Fracture Energy, G f, of the specimens were measured to verify its size dependency. Epoxy and polyester resin specimens were studied and epoxy resin specimens reinforced specimens with short carbon and glass fibers were considered.