Multiresolution analysis of three-dimensional (3D) surface texture for asphalt pavement friction estimation

Maintaining desired pavement friction is an effective way to reduce the crash rate. Pavement texture plays an important role in tire-pavement friction performance. However, the contribution of texture at different depths or wavelengths to friction measurement has not been fully understood. This study conducts a multiresolution analysis using three-dimensional (3D) asphalt pavement texture data to correlate pavement texture to friction measurements. Between 2014 and 2018, multiple rounds of pavement texture and friction data were acquired on two field sites. The top-surface topography of 3D texture data is sliced with eight depths to explore the critical contact depth between pavement texture and tire rubber for friction testing. At each depth, 3D texture data is decomposed into sub-images via discrete wavelet transform to extract texture features at 11 wavelengths ranging from 0.1 mm to 102.4 mm. Subsequently, the wavelet energy of each wavelength is calculated as the texture indicator. Finally, the texture energy matrix at different wavelengths and depths along with the ambient temperature during friction testing are correlated with the measured friction data using cross-validation and step-wise multivariate linear regression. The pavement texture of wavelengths up to 3.2 mm at the top 2.5 mm of top-surface topography is identified as the critical contact zone for pavement-tire interaction.