Study on adhesion of asphalt using AFM tip modified with mineral particles

Adhesion between asphalt binders and aggregates is important to the performance of pavement. Atomic force microscopy is commonly used to measure the adhesive forces of asphalt binders. In this paper, AFM probe tips were modified with four types of spherical mineral particles: limestone, basalt, granite and sandstone. These were prepared by planetary ball mill grinding and their compositions investigated by X-ray diffraction. The modified tips were used to investigate the adhesive forces at mineral particle asphalt substrate interfaces. Adhesive forces increased obviously with SiO2 content. This indicates that physical-adsorption plays a greater role in interfaciale adhesion than chemical adsorption. Linear model, single-factor analysis of variance, and interquartile analyses were also applied to investigatinge the distributions of adhesive force. It was found that different degrees of distributions might be attributable to the different microstructures of the mineral particle surfaces. (C) 2019 Elsevier Ltd. All rights reserved.