Thermal wave imaging for non-destructive testing and evaluation of reinforced concrete structures

Abstract

There is a very long tradition in the building industry of using reinforced concrete structures, due to their low cost, high strength, robustness and sustainability, along with the ready availability of raw materials. These characteristics make them useful in the construction of buildings, flyovers, nuclear power plants, etc. However, they also have some drawbacks, such as poor tensile strength and ductility, which can lead to the formation of cracks in the structures. These cracks may allow for the penetration of chlorides, resulting in corrosion in the reinforcement. Quality control, maintenance and planning for the restoration of these structures demands a suitable non-destructive testing and evaluation method for wide-area monitoring, to detect the hidden corrosion of the rebar at an early stage. Infrared thermal wave imaging (ITWI) has emerged as a valuable technique for the non-destructive testing and evaluation of reinforced concrete structures due to its full-field, fast and remote inspection capabilities when monitoring subsurface rebar corrosion. The present work highlights the corrosion detection capabilities of the frequency-modulated thermal wave imaging (FMTWI) technique for the health monitoring of reinforced rebar.