Surface Energy Characteristics of Natural Minerals and Their Impact of Aggregate-Bitumen Bond Strengths and Asphalt Mixture Durability

摘要

The surface free energy of a solid is a material property that influences its interaction with othersolids, liquids and gases. Mineral aggregates are mixed with bitumen in the production ofasphalt mixtures and the interaction of aggregates with bitumen, water or chemical modifiersimpacts the overall performance of the mixtures and, in turn, the pavement structure. Acomprehensive characterization of the minerals that make up these aggregates can be used toexplain the interactions among the aggregates and components used to bind the aggregatesincluding bitumen, water or chemical additives. This paper combines several techniques toquantify and describe or catalog mineral properties. These properties include (primarily) surfacefree energy, specific surface area, and surface carbon content of some of the most commonminerals found in aggregates. The paper also presents data that exemplify how this informationcan be used to characterize the moisture induced stripping potential for different bitumen-mineralcombinations. Results indicate that a simple energy ratio calculated based on adhesive bondenergies from surface free energy measurements of the minerals and the bitumen can predictperformance in asphalt mixtures, and a few minerals that can form thermodynamically stablebonds with some bitumens that are inherently resistant to stripping.