On Measurement of the Depth and the Diameter of Steel Bars in Reinforced Concrete Using Electromagnetic Wave (Radar)

The present paper analyzes the propagation paths of the electromagnetic wave of a radar in reinforced concrete using Snell´s law. Using the derived paths, the depth and the diameter of the reinforcing bars are measured by making a pattern matching between the modeled received wave signal and the actual received wave signal of the radar. The dielectric constant of the concrete is also measured together with the depth and the diameter, because the propagation speed is a function of the dielectric constant. Lastly, the effectiveness of the method is demonstrated by experiments. Especially, a high accuracy of measurement is achieved for the depth, while concerning the diameter one or two units in JIS standard is obtained and thus a new additional device is also suggested