Computation of fractal dimension on conductive path of conductive asphalt concrete

Distribution of the conductive paths in the conductive asphalt concrete seems as rough, disorder and random, but it has self-similar fractal characteristics in statistics. It use the fractal theory to study on the distribution characteristics of the conductive paths. The conductive process of asphalt concrete turned from insulator to conductor could be described quantitatively by fractal dimensions. When the graphite content is 4 vol.%-14 vol.%, the fractal dimension which is measured by box-counting is 1.22-1.89. Comparing the relationship between fractal dimension and resistance change, it can be found that the changes in fractal dimension and resistivity have a similar trend with the changes of graphite content. There exists a percolation threshold when fractal dimension and the resistivity change, and the fractal dimension and resistivity change little once the graphite content exceeds the threshold. The physical significance of fractal dimension reflects the changes of the conductive paths in the asphalt mixture.