Various failure criterions have been used for the nonlinear analysis of concrete and reinforced concrete structures. To get more accurate results from the analyses, the selected failure criterion must be appropriate with the characteristics of problem and the assumptions made in the criterion should comply with the characteristics of problem. In this study, an experimental investigation was carried out to determine the cohesion (c) and internal friction angle (.) values, which are in the compressive strength range of 14.4 MPa <= f(cm) (cube) <= 47.0 MPa (2.03 ksi <= f(cm) (cube) <= 6.82 ksi) that are used in failure criterions such as Mohr-Coulomb and Drucker-Prager preferred in end unit analyses for concrete and reinforced concrete structures. Tests are performed by using the direct shear test system, which is designed and produced for this study. Finally, cohesion and internal friction angle were determined between 2.94 and 12.34 MPa (0.43 and 1.79 ksi) and 29.8 and 41.7 degrees, respectively.