Self-structural Health Monitoring Function of RC Structures with HCFRP Sensors

Abstract

In this article, the self-structural health monitoring (SHM) function of reinforced concrete (RC) structures is studied with the application of a novel type of hybrid carbon fiber-reinforced polymer (HCFRP) sensors that are characterized by broad-based and distributed sensing capabilities. The HCFRP composite sensors are designed and fabricated to consist of three types of carbon tows, wherein the active materials are carbon tows by virtue of their electrical conductivity and piezoresistivity. Two types of HCFRP sensors, with and without pretreatment, are fabricated. First, the sensing properties of these two types of sensors are tested under uniaxial tension. Then, the HCFRP sensors are bonded with epoxy resins on the bottom concrete surface of RC beams to monitor the strain, the yielding of reinforcing steel bars, and the initiation and propagation of cracks in concrete. The experimental results show that the pretreatment can enhance the change in electrical resistance more than 100 times, especially in a low-strain range before the rupture of carbon tows. With the application of HCFRP sensors, the structural health, including the average strain amplitude, the yielding of reinforcing steel bars, the deformation of the beams, and the initiation and propagation of cracks in RC structures, can be monitored in a real-time manner.