Inner dimension detection of open and buried crack in asphalt pavement based on Rayleigh wave method

Abstract

In this paper, the finite element models of asphalt pavement with open vertical/inclined crack and buried vertical crack were established, and the propagation route and energy distribution of Rayleigh wave near the cracks were researched. Propagation time difference method was put forward to calculate the inner depth and angle of open inclined crack and horizontal position of buried vertical crack. The relationship between normalized depth (ND) and displacement attenuation coefficient (DAC) indexes of open and buried vertical cracks were studied further, and the displacement attenuation method for back calculating the depth of open vertical crack and buried depth and horizontal position of buried crack was established. On-site detection was carried out and the applicability of above methods were researched. The viscoelastic property of asphalt pavement can be eliminated by detecting in low environment temperature, while the attenuation correction method was put forward to reduce the influence of heterogeneous property in on-site detecting. Results show that for slender vertical cracks, the crack width and depth have little influence on DAC-ND curve. When DAC value is 0.1, the wavelength corresponding to the center frequency of Rayleigh wave basically equals to the crack depth. For buried vertical crack, DAC-ND curves obtained by changing buried depth and changing center frequency are basically consistence when DAC value is lower than 0.8. The theoretical feasibility of propagation time difference method was confirmed, but the error amplification is severe. Vertical displacement attenuation method has much higher on-site detection accuracy in crack inner depth detection.