Road Radar In The Rigid Pavement Empty Identify Applied Research

Void beneath slabs is the generally disease of the rigid pavement. Its identification and reinforcement should be completed promptly. Otherwise void will result in greater economic losses. Currently, void identification mainly relied on acoustic attack, coring, deflection testing methods. Ground Penetrating Radar (GPR), with its speedy, continuous, nondestructive advantages, has been widely used in the field of non-destructive inspection. But its application in rigid pavement void identification has been limited to qualitative judgment based on GPR reflective signals. So back-calculation of void based on GPR reflective signals quantitatively has become one of the hottest issues. Back-calculation of void based on the forward model of electromagnetic wave propagated in rigid pavement with void is a scientific and rational approach. But there isn't rational forward model. Forward simulation of GPR electromagnetic wave is the basis of back-calculation. So the research of the forward simulation of GPR electromagnetic wave propagates in rigid pavement with void was done in this paper.The main research achievements and conclusions are summarized below:1. The forward model of GPR electromagnetic wave propagation in rigid pavement layers is developed based on of electromagnetic theory. The dielectric of pavement material in this model is complex dielectric constant. In the other words, the absorption effect of electromagnetic wave in pavement material was considered, which makes the forward model more rational for rigid pavement because the cement concrete is high-absorption material;2. Based on the forward model, the forward simulating program is developed in this paper. And the reflected GPR waveform propagated in single layer concrete slab and multilayered rigid pavements are simulated by this program respectively, compared with the measured signal, validates the programs are reasonable and accurate;3. In this paper, the 1D forward model of GPR electromagnetic wave which propagated in rigid pavement with void is developed. This 1D model considers the vertical dimension only. Through the forward simulating, the reflective signals of GPR electromagnetic wave propagated in rigid pavements are analyzed, which have void of water or air beneath slabs. The simulated results provided theory basic for 2D-simulation;4. Based on 1D simulation, the 2D forward model of GPR electromagnetic wave which propagated in rigid pavement with void is developed. This 2D model considers the vertical and level dimension. Through the forward simulation, the GPR reflective signals in square, cruciform and circle void is analyzed. And the effect on reflective signals of dimension and depth are analyzed too.The achievements of this paper provide theoretical basis for back-calculation of void identification and pave a completely new way for application of GPR in rigid pavement void identification. The achievements radically solve the key problems of the long-term wander of GPR in identifying void quantitatively. So the achievements of this paper will contribute a lot for GPR applied technology.