Predicted Affinity Ratio between Asphalt Binder and Aggregate

Affinity is a term used to describe the amount of the adhesion bond between asphalt binder and aggregate. Adhesion force may be used as indicator to the amount of energy or work required to breakdown the adhesive bond between asphalt binder and aggregate. In order to study affinity between asphalt binder and aggregate, a modified device is manufacture locally similar to Rolling Bottle Test (RBT) to Predicted the degree of affinity between asphalt binder and aggregate; taking into consideration mineral composition with physical properties of asphalt binder to measure required force to separate asphalt binder from aggregate surface. In this study, suggest new parameters to represent the stripping or affinity phenomena (affinity and stripping ratio) and the time required to make balance between them. From the experimental work result, the affinity ratio of aggregate brought from Dohuk region was 52 % after 24hr of rolling time period which is less than other type because of its mineral composition (high percent of calcite and dolomite which increase ability to resist stripping), pore size and stiffness of aggregate particle. In other hand, the stripping ratio of aggregate brought from al-Taji quarry was 80% after 24hr of rolling time which represent worse case in affinity of aggregate-asphalt binder system due to increased percent of quartz in mineral composition (greater than 80%) and so reduced ability of aggregate to resist stripping