Measuring the diameter of reinforcing bars in concrete nondestructively using electromagnetic wave radar

A method to measure the diameter of deformed bars in reinforced concrete structures using an electromagnetic wave radar is proposed. This method focuses on the measurement of the ribpsilas pitch of the bar and then obtains the diameter of the bar from the standard relationship between the ribpsilas pitch and the diameter. For the measurement of the pitch, variation of the propagation times of the electromagnetic waves to and from the bar along its length is first obtained and then Kalman filter and maximum likelihood method is applied to the dynamic model of the propagation time variation. Lastly, the frequency analysis of the proposed method is proved to be more reliable than the well-known FFT by experiment.