Relationship between bond energy and total work of fracture for asphalt binder-aggregate systems

Surface free energy is a thermodynamic material property representing the work required to create new surfaces of unit area in a vacuum. Surface free energy has been used to quantify and screen both the cohesive bond energy of asphalt binders and the adhesive bond energy of asphalt binder–aggregate interfaces in wet and dry conditions. The bond energy is computed based on the surface free energies of the constituent materials. The total work of fracture is the cumulative effect of energies applied to the sample to create two new surfaces of unit area. These energies include the bond energy, calculated from surface free energy, dissipated plastic energy, and dissipated viscoelastic energy. This paper presents experimental results from a series of pull-off tests using asphalt binder-aggregate samples that demonstrate the relationship between bond energy and total work of fracture. In order to fully explore this relationship, temperature, loading rate, specimen geometry, and moisture content were varied.