X-ray computed tomography and aggregate image system (AIMS) for studying hot mix asphalt and aggregates

Abstract

Achieving reliable pavement design, durable roadway structures and effective maintenance and rehabilitation plans requires the suitable characterisation of the materials used in pavement construction. This paper describes two nondestructive techniques based on image acquisition and analysis and their successful application in pavement engineering: X-ray computed tomography (X-ray CT) and aggregate imaging system (AIMS). The former has been used for characterising the internal structure of asphalt mixes to analyse and model their performance; it has been particularly used for studying the content, size, distribution and connectivity of air-voids and these variables’ relationship with moisture damage susceptibility, capillarity and permeability within the mixes. AIMS was intended for characterising aggregates’ morphological properties (i.e., form, angularity and texture). This technique provides important advantages regarding the standard methods used for obtaining the same aggregate properties: it is objective, reliable, reproducible and can be carried out quickly. This paper was aimed at describing these two techniques’ theoretical backgrounds, mention some recent applications and provide insight into how existing characterisation of materials used in pavement construction can be improved.