BACKGROUND

The surface energy of an aggregate particle determines its affinity for both inorganic and organic binders as well as for water. The surface energy of an asphalt binder affects its ability to adhere to an aggregate particle surface and, thus, the long-term strength and stability of the composite material. Interactions among aggregate particles, binders, and water can also influence the development and longevity of binder adhesion, most notably, in the stripping of asphalt binder from aggregate by moisture. Therefore, the ability to characterize asphalt binders and aggregates by measurement of their surface energies could lead to improved asphalt pavement performance through development of application-specific materials selection criteria, project-specific matching of the characteristics of binders and aggregates, and identification of additives or treatments that improve binder-aggregate compatibility.

OBJECTIVE

The objective of this study was to develop and conduct limited validation of surface energy measurement methodology for characterization of aggregates, asphalt binders, and additives. The expectation is that this methodology will ultimately be used as a tool for routine screening and selection of materials for optimum performance of asphalt pavements.

Product Availability: A summary of the project final report has been published as NCHRP Research Results Digest 316. The complete report is available as NCHRP Web-Only Document 104.