Quantitative Analysis of Aggregate Based on Hough Transform

Abstract

Deformations in asphalt pavements continue to create problems for pavement agencies. One factor that has been identified as contributing to the potential of asphalt concrete to deform is the angularity of particles in the asphalt and aggregate mix. A new video-based method of measuring angularity based on the properties of the Hough transform, a powerful mathematical tool commonly used to detect long straight lines in video images, is presented. The method detects and measures the length of any straight edge in a two-dimensional image of a particle that is then used to quantify the particle angularity. The technique resolved three different test patterns independent of size and angle of rotation. Seven sands were analyzed with the method. The results were consistent with the known qualities of the sands. Although still limited as an engineering application, shape analysis of aggregate by video imaging has the potential to provide insight into the mechanisms of pavement deformation and may provide a basis for specifications or guidelines for the use of manufactured and natural sands in asphalt concrete.