การตรวจสอบแบบจำลองโพรงใต้ผิวทางคอนกรีตด้วยวิธีหยั่งลึกด้วยสัญญาณเรดาร์

Abstract

Void under concrete pavement is a major problem that results in damaging of concrete pavements. Detecting such a void is quite difficult because the void is normally located under the pavement and it will not be able to be observed without any signs on the pavement surface.  This study investigated the capabilities of ground penetrating radar (GPR) technique for void detection. The main objective was to determine the appropriate data acquisitions and visualization techniques of GPR data to provide a better image of survey results. In this study, the GPR data were acquired using both 400 and 900 MHz frequency antennas. Then, all 2D profiles were combined to create a 3D GPR model. Additionally, the GPR data were also converted into the frequency, phase, and amplitude domain using Hilbert transform. From the results of this study, the image obtained from the 900 MHz frequency antenna provided better resolution while the data from the 400 MHz frequency antenna gave a greater depth of penetration, but its resolution was less than 900 MHz. For 2D profile, it is good for viewing the shape and depth of the voids. In contrast, the 3D image makes it possible to see the boundary of the voids from the top view. The results also concluded that time domain GPR data provided clearer shape and depth of the voids. However, the data from Hilbert transform gave the better position of voids.