Relationships between internal structure and surface texture of asphalt mixtures

Asphalt mixture is a multi-phase material composed of coarse aggregate, asphalt mortar and air voids. It is of interest to study how the distribution of internal phases of asphalt mixture would affect pavement surface texture. This is an area that has not received much attention. In an attempt to establish a relationship between the internal structure of an asphalt mixture and its surface texture, this paper employs a 2-dimension image-based internal structure analysis method (2D-IISAM) to characterise the aggregate arrangement, voids distribution and mortar distribution of an asphalt mixture. The internal structure properties of 28 different asphalt mixtures were evaluated by 2D-IISAM, and their corresponding surface texture properties were evaluated by sand patch method and 2-Dimension Image-based Texture Analysis Method (2D-ITAM), respectively. The relationships between the surface texture and the internal structure parameters of the asphalt mixtures studied were established by the Levenberg-Marquarat and generalised global optimisation algorithm. The results suggest that the surface texture of an asphalt pavement is significantly influenced by its internal structural properties. Regression relationships were developed to predict surface texture from the internal structure of an asphalt texture, and vice versa.