Description
Reinforced concrete structures are widely used in civil engineering owing to their versatility, strength, and durability. One of the most recommended methods for rebar mapping is Ground-Penetrating Radar (GPR) because of its non-destructive and non-invasive character. In concrete mapping, GPR is mainly used for locating subsurface objects (rebars, tendons, ducts), measuring concrete cover, mapping mesh configuration (spacing), and detecting bottom of slab. To achieve these, concrete scanning GPR practitioners often need very high-resolution images. This work presents a comparison in rebar mapping between two GPR systems with different modulation techniques: Stepped frequency continuous wave (SFCW) and pulsed radar. The SFCW system used has a frequency range of 400-6000 MHz, while the pulsed system used a ground-coupled central frequency antenna of 2.3 GHz. Measurements were conducted on laboratory specimens, with rebar diameters ranging from 8 to 32 mm. Three different specimens were used, with one for calibration and other two to analyze both the horizontal and vertical resolutions of the frequency antennas.
