Abstract
For the measurement of the diameter of deformed bars in concrete, an electromagnetic wave (EMW) radar is used which scans along the bar. In our previous method, the radar was run while keeping it in contact with the concrete surface, because this is the usual procedure of scanning with a radar. This resulted in a larger angle of incidence of the EMW to the bar, which consequently elevated the frequency of receiving reflections both from the rib and the base of the bar simultaneously. Therefore, the frequency of erroneous measurement of the propagation time of the EMW to the point on the bar just below the radar and back became large. This consequently greatly affected the success in the measurement of the diameter. Therefore, the present paper proposes a new method. The new method introduces a better scanning procedure, which involves the lift-off of the radar during the scanning. Experiments show the comparison of the successful measurements with and without the lift-off of the radar and verifies the effectiveness of the method.
