Load-deflection behaviour of reinforced beams with high strength concrete (HSC) and ultra high strength concrete (UHSC) were studied based on experimental investigations. Four concretes including one HSC and three UHSC were considered for construction of beam specimens. Two different cross-sections of reinforced beams namely Type A and Type B were considered for testing under single point loading. In addition, three sets of Type B beam were tested with three different shear span to depth ratio (a/d) for each concrete mix. The test results confirmed that flexural strength of fibre reinforced concrete increases with the increase of compressive strength of concrete and the initial stiffness of UHSC are very high compared to HSC. It was observed that Type B beam with a/d ratio less than 2 show the pattern of shear failure. As such, a theoretical model was studied to verify the performance and the shear load capacity of beams.