Nondestructive detection of delamination in painted concrete structures through square pulse thermography

• Published in: Journal of Building Engineering Vol. 70; p. 106360
• Main Authors: Ta, Quang Tai, Mac, Van Ha, Huh, Jungwon, Yim, Hong Jae, Tran, Quang Huy
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2023
• Subjects: Delamination; Empirical thermal diffusivity; Infrared thermography (IRT); Painted concrete; Square pulse thermography (SPT); Painted concrete; Empirical thermal diffusivity; Delamination; Infrared thermography (IRT); Square pulse thermography (SPT)
• ISSN: 2352-7102; 2352-7102
• DOI: 10.1016/j.jobe.2023.106360

Active infrared thermography (IRT) is effective for detecting and characterizing subsurface defects in concrete structures. Even though painted concrete (PCo) structures have been applied worldwide (especially for buildings) and subsurface defects, such as delaminations, can develop in their core, active IRT-based defect detection in previous studies focused on normal concrete (NCo) structures rather than PCo structures. Hence, the detectability of delaminations in NCo and PCo structures is investigated in the present study by applying square pulse thermography (SPT), a common approach for active IRT. The results demonstrated that delaminations in PCo, under the same parameters, are more detectable in IR images than in NCo structures. In addition, the effect of the width-to-depth ratio of a defect in PCo structures on the detectability during SPT inspections is presented. Interestingly, overheating is evaluated to determine an effective heating regime for SPT surveys on PCo structures. Finally, the empirical thermal diffusivity coefficient of PCo structures is estimated, which has not been previously determined. •Active IRT is effective in detecting defects in painted concrete (PCo) structures.•Delaminations in PCo are more detectable than those in normal concrete structures.•The detectability of a defect in PCo parts depends on its width-to-depth ratio.•The efficient heating time is proposed to detect shallow defects in PCo structures.•The empirical thermal diffusivity coefficient of PCo structures is provided.