Evaluation of microwave aging impact on asphalt mixtures

Abstract

The beneficial effects of applying microwave energy in asphalt pavements maintenance are receiving increasing attention recently, while its aging impact remains less explored. This study aims to investigate the microwave aging impact on asphalt binders. Different microwave heating cycles are applied on steel slag asphalt mixtures, and the aging effect on extracted asphalt binders, including the physical, rheological properties and infrared spectra, are evaluated with penetration and softening point tests, Dynamic Shear Rheometer (DSR), and Fourier Transform Infrared (FTIR) spectroscopy. Results indicate that the aging issue occurs on asphalt binder after the application of MH treatment. A relatively apparent deterioration can be observed in the physical and rheological properties during the first 10 MH cycles, and minor changes can be further detected during the later cycles. In addition, the microwave radiation also exerts changes in asphalt components, i.e. sulfoxide groups, while the changes in carbonyl groups are not significant.