GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 3.2 ___ GNGTS 2023 Results and discussions The acquired radargrams were elaborated with ReflexW (Sandmeier software). The envelope filter, by using the Hilbert transform, was applied to the acquired radargrams. All the processed GPR data were exported and analyzed with ad hoc script permitting to obtain the single A-Scan traces of the radargram in correspondence with the steel rebar placed exactly in the middle of the sample. These traces corresponding to the steel rebar were numerically analyzed each single radargram for the entire length of the sample for all the days of investigation carried out on the concrete sample. The described procedure permitted to analyze the variations of the envelope signal as corrosion increases. The envelope data set of each radargrams was compared with the previous one and the trace corresponding to the steel rebar was studied on all radargrams. The GPR data are currently being studied and integrated with the potential data obtained. With these tests we want to verify if, as with the previous studies we carried out on concrete samples, it is possible to correlate a variation of the electromagnetic signal with an increase in the corrosion products amount formed at the concrete/steel rebar interface, due to iron oxidation reactions. We also want to obtain information that allows us to study the corrosion of the steel rebar from a quantitative point of view. In previous tests we observed an increase of the envelope signal as corrosion products amount increased. Moreover, a greater increase in the envelope signal was observed where the corrosion phenomena were particularly localized in the steel rebar embedded in the concrete sample. In these tests we want to check the resolution we can get from GPR surveys, and we also want to find information that allows us to study the corrosion of the reinforcement from a quantitative point of view. Moreover, extrapolating laboratory results performed with a single rebar to a large structure with interconnected rebars thus remains challenging. Therefore, during the next experiments, special care must be taken regarding the design and preparation of the samples to obtain meaningful information for field application. Figure 1: Laboratory concrete sample and acquisition with the GPR C-TRUE antenna. References