Study on Design Parameters of Aggregate Based on Surface Texture Characteristic of HMA

In order to realise an optimised asphalt mixture design according to surface texture properties, the distributions along with wavelengths of the surface texture of asphalt mixtures, having different aggregate design parameters, were analysed using the testing method of levels and distributions of asphalt mixture surface texture, which was developed based on image analysis techniques. The indicators (i.e., characteristic wavelength and level of characteristic wavelength) were proposed, to characterise the overall properties of the asphalt mixture surface texture. The correlations between the aggregate sizes in different passing ratios and asphalt mixture surface texture levels were analysed. The irregularity and fragments of aggregate gradation were obtained according to the fractal theory. Following this, the shapes and distributions of aggregates in the asphalt mixture were studied. The results indicate that D90, which is the sieve size in the 90% passing ratio, is an ideal index for representing the entire aggregate particle size. Furthermore, factual dimensions can reflect the irregularity and fragments of aggregate gradation. The regularity and sine of the aggregate direction angle can be used to represent the aggregate shape and distribution in the asphalt mixture.