WATER INFILTRATION DETECTION OF CONCRETE STRUCTURES USING INTEGRATED CARBON FIBER SENSORS
This article aims to develop the sensory possibilities of carbon rovings used as built-in leakage sensors to perform concrete pipelines' structural health monitoring. The sensitivity of electromechanical behavior of carbon rovings allows the researchers to use the rovings as leakage sensors. This way the concrete pipelines can be surveyed remotely and nondestructively. In this study, the textile-reinforced concrete (TRC) specimens were manufactured using woven textile of glass and carbon rovings. The specimens were tested for three-point bending. As a result, micro and macro cracking of concrete took place imitating operational damage of a real pipe. Later on, the specimens were locally wetted in the cracked areas while monitoring of reinforcing carbon rovings electrical resistivity was carried out. The measurements showed relative changes in electrical resistivity up to 87% of the initial value. The significant changes in the carbon roving's electromechanical parameters allow the researchers to indicate piping failures causing leakage. Average values of carbon rovings' electrical resistivity relative changes reached 48%, 6%, 13%, and 6% for different samples. The resistance variation behavior is heterogeneous and represents a complex of sharp shifts and smooth decreases. Additionally, preliminary monitoring of carbon rovings electrical resistivity with no wetting had been carried out to compare the wetting event resistance changes and the incidental interference of the electrical signal. The short-term resistance changes turned out to be insignificant, but the long-term variation of electrical resistance after the wetting event was far outweighing the background signal disturbances. In conclusion, the carbon rovings are applicable to be used as built-in sensors for concrete pipelines' structural health assessment.