To evaluate the homogeneity of asphalt mixtures, the images of sections obtained by cutting the asphalt mixtures specimen horizontally or vertically were analyzed with digital image processing techniques, and the particle area ratio was achieved by app lying sector scan for horizontal specimen and vertical scan for vertical one. The research result indicates that the influence of random distribution of aggregates in cutting the specimen can be eliminated by using colored aggregates to distinguish coarse and fine aggregates and using color threshold to segment the images. Choosing three typ ical gradations, p roving particle area ratio obeying normal distribution and using the variability of particle area ratio as an index, it is feasible to quantitatively evaluate the homogeneity of asphalt mixtures.

       Key words: asphalt mixture; digital image processing; homogeneity; colored aggregate; particle area ratio