A novel approach to predict the rheological properties of rejuvenated binder subject to secondary aging

Abstract

The recycling of asphalt concrete pavement not only requires to restore the original properties of reclaimed asphalt pavement (RAP) materials, but also consider the properties due to secondary aging simultaneously. Therefore, in order to design recycled asphalt mixtures for construction of sustainable pavement with good performances, it is very important to understand and predicted the viscoelastic behaviors of rejuvenated binders. However, limited studies on the effect of rejuvenator dosage and secondary aging in the rheological behavior of rejuvenated binder are reported. In this study, a novel approach was used to construct the dosage-aging master curves to describe and predict the viscoelastic behaviors of rejuvenated binders considering the effect of rejuvenator dosage, aging time and aging temperature. Experimental data of complex modulus and phase angle were used to validate the proposed approach. Rejuvenated binders with rejuvenators at four dosages were aged at various aging temperature and times. Complex shear modulus and phase angle isotherms of each rejuvenated binders for a range of frequencies were constructed simply starting from time-temperature superposed master curves. Two rotations and horizontal shifts procedure were applied to the master curves. Finally, the dosage-aging complex modulus and phase angle master curves were proposed. It was found the twice rotation of master curves of rejuvenated binder process was used to change the shapes of the master curves due to rejuvenator dosage and aging based on the dosage-aging rotation factor. The twice horizontally shifted process was used to shift the master curves after twice rotation to the master curves at the reference dosage, aging time and temperature based on the dosage-aging horizontal shift factor. The twice rotation and horizontal shift processes are suitable for rejuvenated binder for using other dosage under other aging conditions, the predicted dosage-aging master curves can be obtained and is good accordance with the measured master curve. Therefore, the complex shear modulus and phase angle values of rejuvenated binders over a range of dosages at any aging time and temperature can be predicted without actual testing.