ABSTRACT
The use of reclaimed asphalt pavement (RAP) in new hot-mix asphalt can reduce the consumption of virgin materials required, thereby conserving natural resources and also incentivize circular economy. However, the RAP content together with degree of aged binder activity (DoA) that contributes to the properties of recycled asphalt concrete would considerably affect the mixture design process. In addition, the mixture tests associated with pavement performance should be employed to design recycled asphalt concrete in order to verify the performance-based test methods for routine design of the recycled asphalt mixtures. The objectives of this research were to evaluate the effects of RAP content and DoA on the properties of the recycles asphalt mixtures in terms of rutting and cracking performances. The two pavement-related performance were assessed using wheel tracking test and IDEAL-CT. A clear understanding of design procedure with balanced performance was established based on performance-based test results in order to increase the RAP content in the recycled asphalt concrete without compromising pavement performance. The results indicated that the test data associated with the balanced performance were consistent when the DoA were between 40 and 60% for the recycled asphalt mixtures regardless of the RAP content. However, it should be noted that the asphalt mixtures with higher RAP content (40 and 60%) would be very sensitive to rutting and cracking performance when taking DoA into account. The DoA with underestimation would cause severe rutting distress for the mixture with high RAP content.
