Electomagnetic modeling of bituminous hot mix superstructure layer thicknesses with finite difference time domain method

In Turkey, the construction and maintenance of highway between cities is carried out by General Directorate of Highway Administration and the construction and maintenance of inner city roads is carried out by municipalities. The engineers who are assigned to the asphalt road construction works by the municipal and highway directorates, have performed destructive test method by taking the core for the quality control services. This technique is destructive method.Instead of this method, usage of ground penetrating radars is increasing with the progress of the technology. However it takes importance to determine performance of modelling with time domain finite difference method (FDTD), before designing ground penetrating radar. FDTD method is one of the most effective electromagnetic techniques to determine system performance. In this study, FDTD method in 2D has been investigated in order to contribute to estimate layer thicknesses of asphalt roads by using GPR.The 2D FDTD is reduced to the transverse magnetic field (TMz) mode with the assumption that the antennas used in the YGR are parallel to the profile direction. The MATLAB algorithm and graphical user interface, which computes the EM wave field at 3 GHz in TMz mode, has been developed. The developed algorithm solves the Maxwell equations in the TMz mode for each step and obtains information about the propagation of electromagnetic waves in the layers of the asphalt road model. As a result, the developed algorithm is applied to 2 layered, 3 layered and 4 layered asphalt road models and layer thicknesses are estimated. In addition, the layer thicknesses calculated by the developed algorithm and the layer thicknesses observed on the radargram have been compared and the accuracy of the algorithm is revealed.