Nondestructive Field Evaluation of Aging Levels of Rejuvenated Asphalt Concrete Pavements

Abstract

This study used a nonlinear ultrasonic approach with noncollinear wave mixing of subsurface longitudinal waves that was capable of evaluating the efficacy of rejuvenators in restoring the original properties of aged asphalt concrete (AC) pavements. AC specimens that were oven aged for 36 h at 135°C were treated on the top surface with a rejuvenator (10% of binder by weight) and left to dwell for prescribed periods of time. After the dwell time, each specimen was nondestructively evaluated. Because in the field, AC pavement acoustic properties (ultrasonic velocities and corresponding attenuations) are unknown, a predetermined fixed-incident angle (based on the AC mixture type) was used; this use allowed for practical implementation in the field. It was observed that the rejuvenator had the effect of restoring the material responses of oven-aged samples to those corresponding to virgin samples. It was also observed that the rejuvenating action was not uniform and depended on the samples’ porosity because of the stochastic nature of AC.