Fractals of aggregates correlated with creep in asphalt concrete

The influence of shape and surface texture of coarse aggregates on the deformation characteristics of asphalt concrete mixtures was evaluated in the laboratory. Shape and surface texture of aggregates was measured using fractal dimension analysis. Seven different aggregate blends of the same gradation containing coarse aggregate from 100% uncrushed to 100% crushed were used to prepare the asphalt concrete mixtures. Measured properties of these mixtures included Marshall and Hveem stability as well as creep and permanent deformation. Fractal dimension analysis was shown to be a viable technique for characterizing aggregate particle shape and surface texture. Researchers found a direct correlation between permanent deformation of asphalt concrete mixtures and surface texture of coarse aggregate particles used in the mixtures. This is indicative that fractal dimension of aggregate particles used to prepare asphalt concrete mixtures is related to rutting and shoving in an asphalt pavement.