The aim of the present study was to investigate the effects of different confinement techniques (i.e., conventional shear reinforcement bars and confinement provided by a geo-grid) on flexural strength of full scaled reinforced concrete beams with and without the use of polypropylene fibers. Few studies have been performed using the geo-grids as shear reinforcement bars, and these were limited by flexural strength tests with scaled structural members. Meanwhile, no study has been performed that elucidates the contribution of geo-grids on bond-slip relationships. This is the subject of the present study. Fifteen reinforced concrete beams were tested under static bending tests for different scenarios. The effects of plastic fibers were examined for flexural strength, energy absorption capacities, bond-slip, and moment-curvature relationships for two different confinement techniques. The test results indicated that the use of geo-grids as a shear reinforcement in the available literature does not show good agreement in terms of performance provided by conventional stirrups. The performance of geo- grids as a shear reinforcement was limited with the use of a greater amount of plastic fibers.