The effect of size on the torsional deformation of polypropylene-reinforced and unreinforced fiber-reinforced concrete

This study investigates the size effect which is supposed to be observed in the strength of concrete specimens with different sizes, in torsional failure of plain and reinforced concrete beams. Specimens with dimensions of 25x25x125mm, 50x50x250 mm and 100x100x500mm were used to analyze the size effect in torsional failure. In order to investigate torsional failure in plain and polypropylene reinforced beams, the load should be applied at specific points. A standard of NPI 100x50x4.5 I beam with the length of 600 mm was used to transfer the load to these specific points where steel supports are placed. These specific locations were determined for having a real values of the torsional failure of concrete beams, these steel supports were placed at the corners of the concrete beam on top and under of the concrete beams. The dimensions of these steel structures are 10x10x5 mm, 20x20x10 mm and 40x40x20 mm.