A sustainable high-viscosity modified asphalt modified with multiple anti-aging agents: Micro-chemical analysis and macro-rheological characterization

This study aimed to use aging inhibition technology to actively improve the environmental aging resistance, thus achieving the sustainable and long-life application of high-viscosity modified asphalt (HVMA). The sustainable HVMAs with different anti-aging agents was prepared, and the long-term environmental aging effect, including solar radiation, heat, and moisture, was simulated using the accelerated environmental aging tester. Then, the chemical and molecular composition of sustainable HVMAs were investigated using Fourier transform infrared spectroscopy test, X-ray photoelectron spectroscopy test, and gel permeation chromatography test. Afterwards, the nano-indentation test was used to study the nanomechanical property of sustainable HVMAs. Finally, the dynamic shear rheology test and linear amplitude sweep test were applied to evaluate the aging resistance, crack resistance, and fatigue resistance of sustainable HVMAs. The results show that environmental aging leads to the rapid oxidation of asphalt molecules and substantial degradation of polymer molecules in HVMA, as evidenced by the transformation of carbon elements from C-C/C-H bonds to C-O/C=O bonds and sulfur elements from C-S-C bonds to S=O/O=S=O bonds. A single anti-aging agent has a little aging inhibition effect, while the compounding of multiple anti-aging agents has a synergistic anti-aging enhancement effect. The combination of UV absorbers and UV blocking agents can absorb/reflect some of the UV rays and delay the UV aging process. However, they cannot effectively prevent the binding of UV-excited reactive radicals with oxygen. In contrast, incorporating antioxidants can allow hydrogen atoms to combine with UV-excited reactive radicals and prevent further oxidation of asphalt molecules. The compound incorporation of UV absorbers, UV blocking agents, and antioxidants can improve the rheology property, crack resistance, and fatigue resistance of aged HVMA, thus effectively promoting the sustainable and long-life application of HVMA.