Measurement radius of reinforcing steel bar in concrete using digital image GPR

Ground penetrating radar (GPR) is currently one of the most efficient sensors used for the detection of dielectric cylindrical objects buried under concrete. Physical and theoretical modeling and experimental results of buried reinforcing steel bar (rebar) are given and studied using measurements of radargram data. This allows for reinforcing steel of radii (1.6 cm, 1 cm) to be detected and estimated from the radargrams. A physical model is presented for the electromagnetic signature of a buried reinforcing steel bar, which takes into account the radius of the rebar. This is achieved by subjecting GPR radargrams to a series of digital image processing stages, followed by different power reflectivity within the energy zone during the motion of the GPR antenna along the reinforced concrete surface. Power reflectivity for vertically oriented migration traces was generated. The distance between variant power reflectivity and the long dimension radius of an energy footprint can be considered when calculating the radius of reinforcing steel bar. The results indicate that, this model is capable of estimating the reinforcing steel bar radius to within 7%. (C) 2008 Elsevier Ltd. All rights reserved.