Quantitative Estimation Method for Rebar Corrosion Degree of RC Structures

It is well-known that not only cracks, which are caused by the expansion of the product due to the corrosion of rebar, occur in concrete, but also a performance of the ultimate strength decreases according to the decrease of cross section in rebar. Moreover, the cavitation and spalling of the covered concrete also occur and then the remarkable decline of durability and ultimate strength will be caused by the accelerated progress of degradation due to the exposure of re-bar to atmosphere. Above all, it seems to be very important that the situation of corrosion of rebar in concrete structure is investigated. The method to investigate the situation most correctly in the present is the way by which chipping and observation by watch at covered concrete. However, it’s difficult realistically to judge the re-bar situation in a wide range in existing structure by a chipping investigation, and the reinforced corrosion situation is often judged partially. In this paper, nondestructive evaluation of corrosion of rebar in reinforce concrete is investigated. Employing the thermal on concrete surface by the thermography, heat stored in reinforcing rebar due to electro-magnetic heating is applied to estimate qualitatively the corrosion degree.