The environmental pollution caused by waste plastics has raised widespread concern within the global academic community. The use of waste plastic in road construction is seen as a future trend for road materials, offering benefits such as energy conservation, pollution reduction, and the enhanced high-temperature performance of asphalt mixtures. However, conventional testing methods have limited the scope of performance measurements for modified asphalt mixtures, and fewer studies have explored the pavement performance of such mixtures. This study evaluated the environmental performance of asphalt mixtures modified with waste plastics. A series of experiments, including rutting tests, low-temperature bending tests, water stability tests, and aging tests, demonstrated that the use of waste plastic-modified asphalt significantly improved high-temperature performance. Notably, with transition dispersants, the rutting resistance improved by 24.5%, and the low-temperature bending strength increased by 15.8%, demonstrating excellent anti-aging properties. Statistical analysis indicated that waste plastic-modified asphalt has superior high-temperature stability and good low-temperature crack resistance.

Semi-rigid bases are widely used in road construction due to their excellent properties, high rigidity, and frost resistance, and they have been in service for many years. However, as the service life increases, the maintenance demands also grow, with traditional maintenance methods still being the primary approach. Based on a typical case using ground-penetrating radar (GPR) technology, this study explores the issue of cracks in semi-rigid bases and their impact on overlay layers. The findings indicate that the overlay layer at semi-rigid base cracks struggles to withstand significant tensile and shear stresses, leading to reflective cracking and reducing pavement durability. To address this problem, this paper investigates the application potential of crushing technology in maintaining semi-rigid bases. Crushing technology has been widely employed in the maintenance of cement concrete panels, effectively eliminating reflective cracks and extending the service life of overlays. Given that semi-rigid bases share similar high-strength characteristics with cement concrete panels, crushing technology shows considerable applicability in semi-rigid base maintenance. This study employs a finite element analysis method to establish a semi-rigid base model under the impact load of multi-hammer equipment. It examines its dynamic mechanical response and evaluates the feasibility and effectiveness of crushing technology for semi-rigid base maintenance. Additionally, this study investigates the influence of the crushed layer’s modulus and thickness on key mechanical design indicators of the overlay and proposes recommendations for optimal design parameters. The research results provide valuable references for the design of the thickness and modulus in maintaining and repairing semi-rigid bases, contributing to improving pavement performance and durability.

Reflection cracking in semi-rigid bases is a widespread distress that undermines highway safety. Priority should be given to this issue to ensure the normal performance of large-scale semi-rigid base asphalt pavements that have reached the end of their service life. At present, scholars have deeply studied and applied the theory of pavement surface layer fracture damage. However, the study of semi-rigid bases only focuses on pavement temperature influence, crack prediction, and reflection crack retardation, and there is a lack of further research on crack-related characteristics. Building on the novel concept of in situ softening for semi-rigid bases, we employ finite element analysis to quantify how transverse crack density affects overall stiffness and derive targeted softening strategies accordingly. By establishing the base micro-cracking treatment cracking block-size influence model, this study analyzes the load-bearing characteristics of cracking blocks of different sizes and recommends optimal block dimensions. This study provides practical guidance for the treatment of semi-rigid bases with maximum efficiency by expanding the application of fracture mechanics at the microscale and providing practical guidance for the high-value rehabilitation of semi-rigid bases.