As part of the research project C-3- Carbon Concrete Composite, 4-point-bending tests to investigate the shear capacity of 25T-beams, strengthened with carbon reinforced concrete, and of five reference beams were carried out.Two different impregnated carbon grids in various strengthening configurations at the beams' webs were tested.The number of reinforcement layers was varied as well as the orientation of the grid in the strengthening layer. Furthermore, the influence of a pre-damage of the RC beam before strengthening and two different shear slendernesses were investigated. A load increase of 25% to 42% times compared to the unstrengthened reference specimens demonstrates the capability of carbon concrete for shear strengthening.