Self-Diagnosing Performance for Fracture in CFGFRP-Reinforced Concrete

Abstract

Concrete reinforced by CFGFRP (carbon fiber-glass fiber-reinforced plastics) composites containing carbon and glass fiber tows with small and large values of ultimate elongation respectively was found to be an intelligent material with a self-diagnosing function for preventing fatal fractures. The electric resistance of the CFGFRP composites increased with increasing load, strain and deflection in the CFGFRP-reinforced concrete. A large change in electric resistance occurred at the point where carbon fiber tows fractured, and the point was controllable by a suitable selection of the type of carbon fibers with different ultimate elongations. Permanent, residual electrical resistance of the CFGFRP composites was observed even after the removal of load, and the changes in the electric resistance was dependent on the maximum load applied. In the application of this method, information on the position of fracture by the self-diagnosis was obtained by the arrangement of the CFGFRP composites in a reinforced concrete. A method based on monitoring changes in electric resistance of the CFGFRP composites during loading and after unloading is a promising method for foreseeing the fracture of the CFGFRP-reinforced concrete by self-diagnosis.