As an alternative to fiber-reinforced polymer (FRP), which has inherent limitations in retrofitting concrete structures, fiber reinforced cementitious matrix (FRCM) systems have been introduced. Nonetheless, most studies suggest that FRP outperforms them in providing structural reinforcement. A comprehensive comparison between FRP and FRCM, especially under identical axial stiffness conditions, has not yet been undertaken. Considering this, eight reinforced concrete beams retrofitted with both external reinforcement methods were experimentally studied, ensuring the external fiber reinforcement ratio remained constant between the two methods. The results indicate that with the same tensile steel reinforcement ratio ρ2ϕ10 s = 0.67% and external fiber reinforcement ratio ρf = 0.08%, the load-carrying capacity of the FRCM-strengthened beam is similar to that of the FRPstrengthened. In beams with the same tensile reinforcement ρ2ϕ10 s = 0.67% and external fiber reinforcement ratios ρf = 0.16%, the load-carrying capacity of the FRCM-strengthened beam is notably higher (~18 %) than that of the FRP-strengthened. Moreover, the load-carrying capacity of the FRCM-strengthened beam significantly surpasses that of the FRP-strengthened (~13 %) in the case of the same tensile reinforcement ratio ρ2ϕ18 s = 2.22% and external fiber reinforcement ratio ρf = 0.08%. In addition to the experimental study, simple models were proposed for the accurate estimation of the debonding strain of FRP- and FRCM-strengthened beams under flexure.

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