Influence of Impactor Diameter on Concrete Thickness Estimation by the Impact-Echo Method
Toshiro KAMADA, Shinya UCHIDA, Hirofumi MAE and Kenta YAMAMOTO
Abstract:Impact-echo method is a nondestructive testing method to estimate the thickness of concrete member. In this method, it is necessary to identify a single peak corresponding to resonance frequency of P-wave reflection between the surface and bottom of concrete plate. Thus, it is important to extract the targeted frequency component due to P-wave reflections. It is found that estimation of concrete thickness is not always easy because many peaks are often observed in the spectrum due to reflection at edge of concrete member. In this study, influence of shape and size of cross section on concrete thickness estimation by the impact -echo method was investigated. As a result, it was revealed that the problem of the generation of unrelated frequency peak for the estimation of concrete thickness could be solved by selecting impactor diameter to obtain 1.5`3 times higher maximum useful frequency than the resonance frequency correspond to concrete thickness. Key Words:Impact-echo method, Concrete thickness, Impactor diameter, Maximum useful frequency