Evaluation of Fatigue Healing Effect of Asphalt Concrete by Pseudostiffness

Abstract

The pseudostrain concept based on the extended nonlinear elastic—viscoelastic correspondence principle has been demonstrated in this research to be an appropriate and efficient method for evaluating microdamage and healing during the fatigue damage process. Pseudostiffness can be used to monitor microdamage and healing during the fatigue test. Pseudostiffness decreases consistently with an increasing number of loading cycles, which indicates that the microdamage occurs during the fatigue test. The significant recovery of pseudostiffness after rest periods indicates that there is a strong healing due to rest periods. The effects of hydrated lime on fatigue microdamage and healing have also been evaluated based on pseudostiffness recovery. The impact of healing during rest periods is evident and substantial. The degree of healing is mixture dependent. The ability of a mixture to heal is largely related to binder properties. Adding hydrated lime to the mixtures tested generally improved the healing potential of the mixtures. In general, stiffer mixtures have better healing and longer rest periods result in greater healing. The mechanism of healing is evaluated by two theories. The initial healing rate is governed by nonpolar surface energy, and the final healing rate is governed by polar surface energy.