Imaging-based direct measurement of aggregate surface area and its application in asphalt mixture design

Abstract

In asphalt mix design, an effective way to prevent asphalt films of improper thickness is to directly coat the aggregate particle with a controlled thickness of the asphalt film, which prerequisites that the total surface area (SA) of aggregate particles in an asphalt mix be accurately measured. This paper introduces an imaging-based approach to measure the SA of a single irregular-shaped aggregate particle from three orthogonal views, based on which the total SA of aggregate particles in a mixture can be determined. The developed SA method is validated by predicting accurate SA results for both regular-shaped and irregular-shaped objects, which are comparable to the SA results measured using a 3D laser scanning device developed for solid shape modelling in manufacturing applications. As an application of the imaging-based SA algorithm, the average asphalt film thicknesses of 18 mixes are calculated based on the SA of the individual aggregate particles in each mixture.

Keywords:

• aggregate
• surface area
• image analysis
• asphalt mixture design