Quantification of Aggregate Morphologic Characteristics as Related to Mechanical Properties of Asphalt Concrete with Improved FTI System

Abstract

This paper introduces the improved Fourier transform interferometry (FTI) system, which captures three-dimensional (3D) high-resolution images of aggregates. The improved FTI system uses the two-dimensional (2D) fast Fourier transform (FFT2) to rapidly measure aggregate morphologic characteristics from these images, including sphericity, flatness ratio, elongation ratio, angularity, and surface texture. Eight aggregate fractions, used in two different stone matrix asphalt (SMA) mixtures, were imaged and the calculated aggregate morphologic characteristics were found to be in good agreement with manual measurement results. The influence of aggregate morphologic characteristics on the mechanical performance of asphalt concrete is further examined on mixtures from Culpeper and Staunton in terms of dynamic modulus, flow number, and fatigue performance in laboratory experiments. Experimental results show that the mechanical performance of Staunton asphalt concrete samples was better than that of those from Culpeper, as was predicted from Staunton’s better aggregate morphologic properties, such as more cubical shapes and more angular and rougher surfaces.