Abstract: In order to quantitatively evaluate the variation of the coarse aggregate alignment in the pitch mixture molding indoors， the digital image processing technology is used to propose a synthetic centroid moment method. The commonly used AC20 and SMA20 pitch mixtures are selected to define the number of rotations and compactions as test specimens of conditional molding for the two types of mixtures. Parameters are extracted through horizontal segmentation of the collected images. The synthetic centroid moments of the 2-D accumulate residual coarse aggregate and the 2-D non-accumulate residual coarse aggregate are computed， respectively. Results show that the synthetic centroid moments vary differently with the number of compactions for the two types of pitch mixture and coarse aggregate. The configuration of SMA20 is excellent after 60 compactions.

Key words: asphalt mixture, configuration, image process, synthesis of center of mass, crush