Refractometric Measurements at the Bitumen-Aggregate Interface

摘要

In this paper, refractometry is used for characterization of the adhesion between bitumen and aggregates. The main purpose of this paper is to find whether preferential adsorption occurs and can be demonstrated in pure and undiluted road-construction bitumen. For this, bitumens from different crudes with different penetration grades and six bitumens with different penetration grades from the same crude are examined in a refractometer. The measurements give indices of refraction of the different bitumens at the bitumen-aggregate interface. In this paper, it is concluded that the indices of refraction are strongly related to the penetration of the bitumens. Clear preferential adsorption was not found from the refractometric measurements at this stage. It is suggested that a change in the composition of the bulk of the bitumen results in a similar change in composition at the aggregate surface.