Removal of the GPR antenna vibration effect through height shifting correction for enhanced multi-layer asphalt pavement thickness determination

Ground-penetrating radar (GPR) can be used for thickness determination of asphalt pavement in a nondestructive manner. However, the accuracy of the existing methods may be affected by the vibrations of GPR antenna caused by tire-pavement interaction. This study proposes using antenna height shifting correction to counteract the effects of vibration. Numerical simulations were performed to illustrate the relationship between antenna height and the reflection amplitude of GPR signal peaks of asphalt layers. A third-order polynomial correlation between antenna height and reflection amplitudes was revealed. A height correction surface reflection (HC-SR) method was developed for multi-asphalt layer thickness prediction, whose performance was validated through field GPR tests and lab measurement of field cores. Results showed that the proposed HC-SR method increased the thickness prediction accuracy by 13.3%, 19.9%, and 17.4% for the first, second, and entire asphalt layer, respectively, compared with the traditional surface reflection (SR) method.