An experimental research program was realized to evaluate the effectiveness of repairing reinforced concrete (R.C.) beams with a layer of sprayed concrete. Nine beams (three series) were tested in total. Series one includes the testing of three reference beams to failure. In series two, three beams were loaded, damaged and repaired by the addition of two reinforcing steel-bars and a layer of sprayed concrete then loaded to failure; the beams of the third series were tested in the same manner as in series (2), except that the reinforcing layer was performed with fibrous concrete. In this paper, the results of experimental tests (ultimate load, deflection, longitudinal strains and cracking shapes) are presented and discussed. Then a mathematical modeling is realised to compare theoretical approach results with experimental observations. In the end, conclusions are presented concerning the reliability of this technique and its practical usage.