| The mechanistic behavior of asphalt mixes becomes considerably complicated when microdamage is introduced into the same body. Based on a literature review, three mechanical behaviors are found during the fatigue tests. They are: microfracture, chemical healing and stress relaxation due to the nature of viscoelastic materials. The correspondence principle is proposed to separate asphalt damage and healing from stress relaxation process.;There is a vast body of work on approximate interrelationships between elastic and viscoelastic properties. In this study, a closed-form solution for pseudo strain was derived with the aim of practical utility. This method will apply well to quasi-static and dynamic problems.;The asphalt healing is a real and measurable phenomenon. It can be verified by testing two asphalt mixes, AAM and AAD, in strain-controlled fatigue tests. The results reveal that AAM binder is consistently a better healer compared with AAD binder.;The assessment of mean microcrack length as a function of loading cycle was based on energy dissipation criteria. A finite element model was used to predict the change in dissipated pseudo strain energy. Schapery's fundamental law of fracture mechanics is further applied to determine the fracture and healing surface energy densities. It confirms that the same fracture properties which control the propagation of visible cracks control the propagation of microcracks. |
