The major objective of this study was to evaluate the potential of image analysis for characterizing air voids in portland cement concrete (PCC), voids and constituents of asphalt concrete (AC), and aggregate gradation in AC. Images for analysis were obtained from a scanning electron microscope (SEM). Sample preparation techniques are presented that enhance signal differences so that backscattered electron (BSE) imaging, which is sensitive to atomic number changes, can be effectively employed. Work with PCC and AC pavement core samples has demonstrated that the low vacuum scanning electron microscope is better suited to doing rapid analyses. The conventional high vacuum SEM can be used for AC and PCC analyses, but some distortion within the sample matrix will occur. Images with improved resolution can be obtained from SEM BSE micrographs. In a BSE image, voids filled with barium sulfate/resin yield excellent contrast in both PCC and AC. There is a good correlation between percent of air by image analysis and linear traverse.