On the Use of Lateral Wave for the Interlayer Debonding Detecting in an Asphalt Airport Pavement Using a Multistatic GPR System

Abstract

In this paper, we focus on the detection of the interlayer debonding of the asphalt airport pavement by the Groundpenetrating Radar (GPR) system. Since the interlayer debonding usually occurs in the shallow region of the asphalt airport pavement (several centimeters), it is difficult to interpret the anomalies or the defects from the GPR signals composed of many waves under the boundary conditions. Moreover, the wavelength of the ordinary GPR system is over several centimeters. Therefore, the spatial resolution of the system is not accurate enough to consider the millimeter thickness of the debonding layer. To overcome these problems, we propose a new method based on evaluating the lateral wave behavior of common midpoint (CMP) gathers collected by a multiple static GPR system. The multi-static GPR system is a stepped frequency continuous wave (SFCW) radar system, which consists of 8 transmitting and 8 receiving bowtie antennas. The system operates in the frequency range from 50 MHz to 1.5 GHz. After the validation of the simulation, the results of the interlayer debonding detection were evaluated by a field experiment obtained at Tokyo International Airport. The proposed method can detect the debonding layers which are less than 1mm. Also, it is shown that our proposed method has a high consistency with the conventional acoustic finding method in the field measurement. It provides an innovative and effective method for the interlayer debonding detection of a partially damaged airport asphalt pavement, which is difficult to be observed by the ordinary GPR signals.

Analysis of Radiation Field Excited by a Vertical Electric Dipole in a Four-Layered Region

“…Approximate formulas were generated by HED buried in a four-layered media using generalized reflection coefficients [17] presented by Lu et al, which indicated that the trapped surface wave and the lateral wave propagate along the air-dielectric boundary and between two dielectric layers. Recently, Zou used lateral wave in a four-layered model for interlayer debonding detection in asphalt airport pavement [18]. The problem addressed in this paper parallels the analysis carried out in published work on the EM field of the horizontal electric dipole (HED) [19].…”

A Review of GPR Application on Transport Infrastructures: Troubleshooting and Best Practices

“…The early detection of debonding is therefore crucial for pavement assessment. The application of GPR in the detection of debonding is usually combined with FWD analysis [75,85], with consistent results validating each other. In addition, the analysis of the GPR signal frequency indicates that the spectrum is sensitive to the structural condition of the pavement, correlating the results with the standardized deflection tests [47] in roads: when comparing damaged zones with undamaged zones, the spectrum bandwidth reduces while the amplitude and the central frequency decreases.…”

“…GPR is also used to evaluate the quality of grouting treatments [78] applied to stabilize damaged pavements. GPR is also used in the assessment of the asphalt layers' interfaces to detect debonding [75,85]. Other studies were focused on the analysis of airports under special conditions: (i) in the case of airports built over the sea, in order to detect the contact between the filled layers and the natural soil under the sea [86]; and (ii) in the study of airports in frozen areas, in order to detect the depth to the permafrost layer [87].…”

“…Even though in many of the applications the study is based on the analysis of anomalies in B-scans [82,86,87], in some cases those analyses are combined with other analyses from amplitudes and data obtained in CMP or WARR surveys [85], detection of reflections patterns in A-scans and B-scans [76], and velocity analysis [81]. In addition, many applications propose the use of arrays and multi-frequency antennas [77,81,83,85].…”

“…However, the clear detection of debonding is only possible in the case of water presence in the debonded zone. Another analysis focused on the assessment of airport pavements [85] refers that the identification of such damage is difficult because it is usually produced at the shallow zone of the pavement structure (within the first several centimeters). However, GPR lateral wave in the CMP data acquisition is highly sensitive to the material properties, and the amplitude maps have proved to be efficient in determining debonding zones in which the high amplitude corresponds with the damaged zones detected by acoustic sounding methods.…”