Estimating the Gradation of Asphalt Mixtures using X-Ray Computerized Tomography and Stereology Method

An attempt at using X-ray computerized tomography (CT) and stereology method to estimate the gradation of asphalt mixtures is made. Using X-ray CT which is a nondestructive test technique to obtain batch of slice images, analyzing these two-dimensional (2-D) slice images, and applying stereology method which is a probability statistical theory, the three-dimensional (3-D) volumetric gradation of coarse aggregate under the assumption of spherical aggregate can be estimated from 2-D area gradation. There is error between the gradations of spherical aggregate assumption and mechanical sieving and a simple method of converting the gradation of spherical aggregate assumption to that of mechanical sieving is proposed. Moreover, a correction factor C is used to convert the gradation of spherical aggregate assumption to that of mechanical sieving so that comparison between these two gradations can be made.