This work investigates the feasibility of identifying steel reinforcing bars in concrete using a fully contactless radar system operating in the X-band. High-frequency electromagnetic inspection is particularly challenging due to attenuation and strong reflections at the air–concrete interface. This study combines numerical simulations and laboratory experiments to assess the sensitivity of microwave scattering measurements to the presence of reinforcement. Ad hoc mini reinforced-concrete pillars, both reinforced and unreinforced, were designed and built as benchmark specimens. Measurements were performed in a bistatic configuration using X-band horn antennas and a vector network analyzer, and were compared with finite-difference time-domain simulations reproducing the experimental setup. The qualitative results, comprising a processing strategy to detect the bars, show a clear agreement between numerical and experimental data and confirm that the scattered field remains sensitive to the presence of reinforcing bars despite unfavorable propagation conditions.
Palladino et al. (Fri,) studied this question.