Abstarct: The major cause of deterioration on steel-reinforced concrete structures exposed to harsh environments, is corrosion of the reinforcing steel. Reinforcing bars made from fiber reinforced polymers, (FRP), are being proposed nowadays as a substitute for steel rebars in concrete subjected to aggressive environments, which may lead to premature corrosion of the steel, such as bridge decks and structures in marine environments. As concrete and FRP rebars are both brittle materials, ductility becomes a great concern. Unless ductility requirements are satisfied, FRP materials cannot be used reliably in structural engineering applications. The primary motivation of this thesis is to investigate the ductility of concrete beams reinforced with brittle FRP composite. In this research, to overcome the lack of ductility of concrete sections reinforced with FRP bars, three approaches were considered; replacing conventional concrete with Polymer- Concrete (PC), replacing conventional concrete with Polymer-Modified-Concrete (PMC) and using ECC. In fact, the purpose of this innovation, is to use the ductility capacity of PC, PMC and ECC. The load-deflection behavior of reinforced concrete beams is calculated by a program in FORTRAN. The beams are discretized into multi-laxyered short elements. The moment-curvature diagram of each element is calculated by applying the assumptions that plane sections remain plane and that the strain in the reinforcement is the same as that in the surrounding concrete. Any stress–strain diagram can be used for concrete and steel. In order to verify the model, the results obtained from the model were compared with those of published paper. It was realized that this model could predict the maximum load carrying capacity with an accuracy of more than 95% compared to experimental results. Minimum ductility requirement of conventional concrete section reinforced with steel rebars, is studied baxsed on ACI 318-14 and Iranian national building code, part 9. The results showed that minimum ductility requirement, approximately equal to 2.