Yu Song

Damp-heat environments significantly accelerate the aging and performance deterioration of asphalt pavements. This study systematically evaluated the performance evolution of base and SBS-modified asphalt binders, as well as their corresponding steel slag and basalt asphalt mixtures, under diverse damp-heat aging conditions (60–80 °C, 90% RH, 0–8 days). Physical and rheological characterizations indicate that base asphalt exhibits a monotonic hardening law during damp-heat aging, whereas SBS-modified asphalt demonstrates a unique two-stage aging process characterized by initial softening followed by hardening. Chemical functional group analysis further confirms that damp-heat aging results from the synergistic effects of early-stage moisture ingress and long-term thermal-oxidative hardening—a process effectively delayed by the SBS polymer network. Furthermore, microscopic morphology and elemental analysis reveal that steel slag aggregates establish a robust dual mechanism to resist moisture erosion through the mechanical interlocking of surface micropores and the chemical anchoring of alkaline constituents. A comprehensive evaluation using the improved radar chart method (f-value) further substantiates that steel slag not only enhances the initial performance of the mixtures but also significantly reduces their time–temperature sensitivity to damp-heat environments. Finally, full-scale field applications in damp-heat regions demonstrate that steel slag asphalt pavements maintain a residual Marshall stability of 87.6% and a texture depth retention rate of 91.5% after service. These results indicate superior early-to-mid-term moisture damage resistance and safety compared to basalt-based pavements, providing critical theoretical and practical support for material design and performance improvement in extreme damp-heat climatic regions.

Asphalt pavement wearing courses are directly exposed to hydrodynamic scouring, fuel erosion, freeze–thaw action, and traffic abrasion, leading to accelerated surface deterioration, skid-resistance loss, frequent maintenance, and increased life-cycle carbon emissions. To address these challenges, this study developed an organosilicon-based erosion- and skid-resistant asphalt wearing course (OES-AWC) through a stepwise material design strategy. An organosilicon-treated asphalt concrete matrix was first prepared to improve resistance to moisture damage, fuel erosion, and ice adhesion, and its curing behavior and optimal dosage were determined. A skid-resistant surface layer was then designed by optimizing the anti-skid aggregate type, organosilicon-to-aggregate ratio, and surface texture. Finally, waterborne epoxy resin was introduced to enhance aggregate anchorage, and the integrated OES-AWC was evaluated in terms of abrasion durability, rutting resistance, long-term skid resistance, and life-cycle impacts. The results show that organosilicon treatment forms a hydrophobic siloxane network, which improves the moisture damage, fuel erosion, and anti-icing resistance of asphalt concrete by 22.0–41.1%. Emery aggregates and the optimized surface structure enhance friction stability, while waterborne epoxy resin significantly suppresses aggregate stripping under repeated wheel loading. Compared with conventional asphalt wearing courses, the optimized OES-AWC increased wear durability by 148.1% while maintaining stable skid resistance under prolonged abrasion. Life-cycle assessment further demonstrates that OES-AWC can reduce carbon emissions by 47.2% and overall costs by 25.0%, with a probability exceeding 90% according to the uncertainty analysis. These findings indicate that OES-AWC provides a durable, low-carbon, and cost-effective maintenance strategy for asphalt pavements exposed to complex service environments.

To determine the preparation parameters of layered double hydroxides (LDHs) + styrene butadiene styrene block copolymer (SBS)-modified asphalt binders (MABs) in engineering applications and identify the structure of LDHs used in asphalt modification, this paper investigated the physical, rheological, and UV aging resistance of LDHs + SBS MABs under various preparation parameters. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and an ultraviolet-visible spectrophotometer (UV-vis) were used to characterize the structure and UV resistance of LDHs and D-LDHs (dissolving from LDHs + SBS MABs). The mechanical properties of LDHs + SBS MABs were studied based on penetration, ductility, softening point, and rotational viscosity tests. The rheological performance and UV aging resistance of LDHs + SBS MABs were assessed using the bending beam rheometer (BBR) test, direct tensile test (DTT), dynamic shear rheometer (DSR) test, and FTIR. The results demonstrated that the crystal and chemical structures of LDHs remain unchanged before and after use in asphalt modification. The optimal preparation parameters of LDHs + SBS MABs were as follows: a preparation temperature of 170 °C, a shearing time of 60 min, and a shearing rate of 4000 r/min. The high-temperature performance of LDHs + SBS MABs improved significantly with LDHs added, and the low-temperature performance slightly decreased. The viscosity of LDHs + SBS MABs with 4 wt% LDHs at 135 °C was 1.920 Pa·s, which was 47.4% higher than that of SBS MABs. The DTT results indicated that SBS MABs have the highest fracture energy (FE) value of 4873 J/m², showing the best low-temperature cracking resistance. In comparison, the FE values of MABs doped with 3 wt% and 4 wt% LDHs are 4518 J/m² and 4248 J/m², respectively, just 7.3% and 12.8% lower than that of ABs without LDHs. The complex modulus aging index (CMAI) of MABs doped with 4% LDHs is 14.3%, which is 15.9% lower than that of SBS MABs, indicating that the anti-ultraviolet aging performance of LDHs + SBS MABs has been improved. FTIR analysis demonstrated that the relative content of C=O (RCC) and S=O (RCS) of LDHs + SBS MABs decreased drastically compared with SBS MABs, indicating that the UV aging resistance of LDHs + SBS MABs was largely enhanced. Furthermore, the segregation test result of 3wt% LDHs + SBS-modified asphalt is 0.3 °C, showing the best compatibility with asphalt.