Rheological Deterioration of High Viscosity High Elasticity Asphalt (HVEA) Under the Coupling Effect UV Aging and Salt Freeze-Thaw (SFT) Cycles

To investigate the deterioration pattern of the rheological properties of high-viscosity high-elasticity asphalt (HVEA) under UV and salt freeze–thaw (SFT) cycle environments, two snowmelt salts were used for coupled aging tests, along with temperature sweep, bending beam rheological (BBR), and Fourier-transform infrared spectroscopy (FT-IR) tests. The results showed that both snowmelt salts could enhance the high-temperature rutting resistance of HVEA, in which the enhancement effect of NaCl was more significant. With the increase in salt concentration, the BBR stiffness of HVEA decreased and then increased, while the m-value showed the opposite trend, indicating that the addition of snowmelt salt impaired its low-temperature creep performance. Additionally, UV-SFT aging would exacerbate the degradation of low-temperature crack resistance. The temperature sensitivity of HVEA gradually decreased with the drop of viscosity temperature sensitivity (VTS) value; salt corrosion further significantly reduced its temperature sensitivity. UV-SFT aging would significantly weaken fatigue performance of HVEA, especially after 15 cycles. FT-IR test showed that UV-SFT resulted in the enhancement of S=O and C=C characteristic peaks, suggesting that the HVEA underwent oxidization and chemical aging, which increased the low-temperature brittleness.