The effect of rejuvenators on the aging resistance of recycled asphalt mixtures

Abstract

Abstract Shortage of natural resources and the high price of bitumen have encouraged the pavement engineers to use high contents of reclaimed asphalt pavement (RAP) material in new asphalt mixtures. Nevertheless, there are a number of problems associated with increasing the RAP content in asphalt mixtures due to the stiff aged bitumen existing in RAP materials such as poor fatigue and cracking performance and low workability. To compensate for this disadvantage, different kinds of rejuvenators are introduced to restore the properties of the aged bitumen. However, the rejuvenated bitumen of RAP material may have low resistance against re-aging and get aged quickly. In this research, oil-based and organic rejuvenators were used in asphalt mixtures containing 50% RAP, and the aging performance of the mixtures was studied by conducting resilient modulus, dynamic creep, indirect tensile fatigue and intermediate-temperature fracture tests on short and long term aged mixtures. The results indicated that the aging resistance of the recycled mixtures was highly affected by the rejuvenator type, and the mixtures containing organic rejuvenator were more susceptible to aging than those containing oil-based rejuvenators.