Static and Fatigue Bond Characteristics of FRP Rebars Embedded in Fiber-reinforced Concrete

A research project was initiated to develop a nonferrous hybrid reinforcement system for concrete bridge decks by using continuous fiber-reinforced polymer (FRP) rebars and discrete randomly distributed polypropylene fibers. This hybrid system may eliminate problems related to the corrosion of steel reinforcement while providing requisite strength, stiffness, and desired ductility, which are shortcomings of FRP reinforcing system in plain concrete. This article presents the results of a part of this research program, i.e., the bond behaviors of this hybrid reinforcing system under monotonic and fatigue loading. Test results indicate that the addition of polypropylene fibers does not increase the ultimate bond strength, while providing enhanced ductile bond behavior. Fatigue loading can increase bond stiffness and bond capacity, while causing more brittle bond behavior. Polypropylene fibers can effectively decrease the bond degradation rate caused by fatigue loading.