Ingeniería e Investigación
versão impressa ISSN 0120-5609
The surface free energy (SFE) of a material is defined as being the energy required in vacuum to create a new surface unit. This property is directly related to a materials fracture resistance and healing properties and to its capacity for creating strong bonds with other materials. The quality of the adhesion between asphalt binders and aggregates can also be assessed by computing these materials work of adhesion. This value can be used as an additional parameter for selecting and appropriately combining materials for hot mix asphalt as well as a component of micromechanical models for fracture and healing within these mixtures. This paper describes in detail a technique used for measuring the SFE of asphalts based on the Wilhelmy plate method and reports the first SFE measurements available for asphalts produced in the Colombian refineries of Barrancabermeja and Apiay. Corresponding results, along with the SFE for different aggregates, were used for analysing differences in the work of adhesion for different asphalt-aggregate combinations in dry conditions. Barrancabermeja asphalt produced the highest work of adhesion amongst the materials analysed here. The results also suggested that the effect of specific mineral filler on asphalt SFE is asphalt-dependent; such effect does not necessarily lead to increasing the SFE for the corresponding asphalt-mineral filler system.
Palavras-chave : asphalt; surface free energy; of adhesion; Wilhelmy plate method; hot mix asphalt; pavement.