Application of Digitised Frequency Modulated Thermal Wave Imaging for Testing and Evaluation of Rebar Corrosion in Concrete Structures: A Numerical Study

The utilization of reinforced concrete structures has an extensive past within the realm of infrastructure due to its economical nature, impressive robustness, ability to withstand adversity, and eco-friendliness, alongside the uncomplicated procurement of essential raw materials. Nevertheless, these structures have certain drawbacks, including limited tensile strength and malleability, resulting in cracks within the edifices. These cracks have the potential to permit the ingress of chlorides, leading to corrosion of the reinforcement. In order to effectively address issues of quality control, upkeep, and strategic renovation of these buildings, it becomes imperative to employ a suitable nondestructive testing and assessment technique for comprehensive surveillance aimed at early detection of hidden rebar corrosion. Infrared thermal wave imaging has arisen as a feasible method for the nondestructive examination and assessment of reinforced concrete structures. This is attributed to its ability to perform comprehensive, remote, and rapid inspections, facilitating the monitoring of subsurface rebar corrosion. The current section introduces an innovative approach known as Digitised frequency modulated thermal wave imaging (DFMTWI) within diverse thermal nondestructive testing methodologies. This technique is put forward to numerically test and evaluate rebar corrosion within concrete structures, and the obtained results are then compared with the frequency-modulated thermal wave imaging (FMTWI) results by taking signal-to-noise ratio (SNR) as a figure of merit.