The interest of diagnosis and maintenance of construction is increasing due to the collapse of infastructures. To obtain the complete, reliable and reproducible data ont he state of the entire structure, various non-destructive techniques are available, Especially, specific constructional characteristics of tunnels make the application of non-destructive tests more difficult. Despite of the complications of these conditions, non-destructive techniques should be capable of providing a description of the state of the tunnel lining, without the removal of the tunnel installations. In this paper, the infrared thermography technique using the difference of surface temperature was studied. The optimum equipment was selected and introduced, the principle, testing method and data anlaysis were investigated. Also, through the case study for inspection of concrete tunnel lining, this technique has proven to be a valuable non-destructive test for detecting the defects such as crack, leakage of water and exfoliation of concrete. The applicability and usefulness of this technique for estimation of concrete tunnel lining have been conformed.
