EXPERIMENTAL BOND BEHAVIOR OF HYBRID RODS FOR CONCRETE REINFORCEMENT

Fiber reinforced plastic (FRP) rods provide certain benefits over stee l as concrete reinforcement, such as corrosion resistance, magnetic an d electrical insulation, light weight, and high strength. FRP composit es can be combined with a steel core to form hybrid reinforcing rods t hat take advantage of properties of both materials. The objective of t his study was to characterize the bond behavior of hybrid FRP rods mad e with braided epoxy-impregnated aramid or poly-vinyl alcohol FRP skin s. Eleven rod types were tested using mio concrete strengths. Specific topics examined were bond strength, slip, and type of failure in conc entric pull-out tests from concrete cubes. From analysis of identical pullout tests on both hybrid and steel rods, information on relative b ond strength and behavior were obtained. It is concluded that strength is similar but slip in hybrid rods is much higher. Hybrid rods failed either by pull-out or splitting the concrete block (with or without y ielding of the steel core). Experimental data showed consistency with similar test results presented in the literature.