Evaluation of Segregation in Asphalt Pavement Surface Using Concave Multifractal Distribution

Surface segregation of asphalt mixtures is a common problem encountered when determining segregation level, which is a criterion of pavement quality evaluation. A method to evaluate segregation levels of asphalt pavement surface was presented based on the concave multifractal characteristic in a binary image of a pavement surface, which was obtained by digital image processing technology and mathematical morphology. The practical value of the proposed method was verified in a newly built asphalt pavement, and the segregation level was divided into five sections based on the recommended texture ratio in practical engineering. Results show that the multifractal spectrum width (Δα) quantifies the uniformity of the concave distribution. The pixel percentage of the concave (P) characterizes the ratio of the occupied area. The product of Δα and P (PWP) was quantified as the surface segregation level, which has good linear relevance with texture depth evaluation results. The proposed evaluation technique (PWP) can be used as an alternative to the sand patch method.