Fracture Analysis of FRP Reinforced Concrete Beams

Carbon/epoxy FRP (Fiber Reinforced Plastic) rebars were produced with the pultrusion technique. Concrete beams reinforced with these rebars were subjected to static and cyclic 3-point bending. Flexural cracking is arrested by an adequate bond between the FRP and the concrete because of the use of a carbon fiber overwrap on the otherwise smooth pultruded rods. In spite of the brittle nature of the FRP rods and the concrete, their combined behavior demonstrate ductility in excess of what is typically expected from reinforced concrete. An analytical evaluation of the fracture energy shows that such ductility is due to the large fraction of the total strain energy that is consumed in the formation of distributed cracking in concrete. Therefore, if an adequate bond can be provided, the strain-to-failure of the FRP determines the ductility and failure mode of FRP reinforced beams.