Testing and evaluation of concrete structures by thermal wave imaging

Abstract

Reinforced concrete structures (RCS) have budding applications in civil engineering due to their high strength, durability, sustainability and flexibility in making complex shapes. However, loss of durability of constructed structures due to premature corrosion of rebar is a major constraint. An initial stage of cracking and corrosion of rebar in concrete is not detectable by visual inspection. With a view to avoid catastrophic failure and massive repair of structures, it is essential to determine damage at low levels. Growing concern about the safety of structure due to premature deterioration has led to a significant demand for advancement of non-destructive testing and evaluation (NDT&E) techniques for monitoring and assessing health of RCS. This paper highlights a whole-field, remote, non-destructive testing and evaluation method based on infrared thermography for identifying hidden corrosion of rebar in a concrete structure. Results shown for both time and frequency domain transform techniques prove the effectiveness of the proposed approach for identification of corrosion in rebar in the concrete specimen.