A good adhesion bond between bitumen and aggregate is the key to hot-mix asphalt (HMA) field performance. One of the adhesion mechanisms at bitumen-aggregate interface is mechanical interlock. In addition, the film thickness of the bitumen coating of the aggregate affects the performance of HMA. In this study, these two phenomena were observed using scanning electronmicroscopy (SEM) incorporated with energy dispersive x-ray analysis system (EDX). The SEM is used to obtain the surface morphology of the bitumen-aggregate system and the EDX analysis can provide an elemental distributionof the different components of the evaluated specimen. The mineralogy andchemical analysis of two aggregates used in the HMA, sandstone and limestone, were analyzed. Their chemical components were also obtained. These chemical analytical results were used along with the EDX analysis to identify the interaction between bitumen-aggregate and to predict the binder filmthickness at the aggregate surface. This study suggests that this technique can be successfully used to observe the binder-aggregate interaction and potentially predicts the binder film thickness.
Samenvatting