Multi-scale performance evaluation and correlation analysis of blended asphalt and recycled asphalt mixtures incorporating high RAP content

Circular utilization of reclaimed asphalt pavement (RAP) becomes a promising trend for sustainable construction due to economic benefits and conservation of non-renewable natural resources. This paper explored properties indexes of blended asphalt and performances of recycled asphalt mixtures (RAM) as well as their correlation analysis, aiming to facilitate further application of asphalt mixtures incorporating high RAP content. Rheological properties and microscopic properties of blended asphalt with virgin asphalt, two rejuvenators and high proportions of aged asphalt were determined. The road performances of high dosage RAP recycled asphalt mixtures were investigated and their links with properties indexes of blended asphalt were also evaluated. The results indicate that incorporating rejuvenators and virgin asphalt in aged asphalt can improve its viscous characteristic and rebalance its colloidal stability, functional group indexes and microstructures. N rejuvenator demonstrates stronger permeation and superior regeneration effect on aged asphalt. The addition of RAP deteriorates moisture susceptibility, cracking resistance and fatigue performance of RAM and conversely promotes its permanent deformation. Rutting critical temperature and creep rate of blended asphalt exhibit higher prediction accuracy on rutting resistance of RAM than |GTS| and complex viscosity, according with quadratic equation. It is suggested that fatigue critical temperature of asphalt might be one of the factors dictating fatigue resistance of RAM with high RAP content.