A quantitative evaluation was conducted on the energy consumption and carbon emissions during the asphalt pavement regeneration process, and the energy consumption and emission ratios during the construction and raw material production stages of the cold and hot regeneration process were obtained. This study applies the theory of life cycle assessment to propose an evaluation framework and calculation method suitable for quantitatively evaluating the environmental impact of the asphalt pavement regeneration process. Firstly, based on the life cycle evaluation theory, the evaluation framework and calculation method applicable to the quantitative study of the environmental impact of asphalt pavement regeneration processes are discussed, and the calculation formulae for the comprehensive energy consumption and comprehensive carbon emission of asphalt pavement regeneration are derived. It is found that the energy consumption and emission in the hot regeneration process account for 50~70% of the total process in the construction stage, and 50~65% of the total process in the cold regeneration process in the raw material production stage. Compared with the milling and resurfacing process, the energy consumption and carbon emission of the asphalt pavement regeneration process are reduced by about 16~66%, and the carbon emission is reduced by about 14~53%, so the energy saving and emission reduction benefits are more significant. The amount of RAP mixing, transportation distance of raw materials and pavement regeneration depth have a great influence on the energy consumption and emission of pavement regeneration. It can provide scientific guidance for the quantitative evaluation of the environmental impact of asphalt pavement regeneration, with a view to providing energy-saving and emission reduction level data support for technology improvement and engineering decisions.

Stone matrix asphalt (SMA) mixture has been widely used in pavement engineering for its preferable in-service performance. However, deterioration of SMA pavement in skid resistance is apparent under traffic loading. There remains lacking attention on skid resistance attenuation of SMA pavement, which in turn is important for skid durability design in practice. Hence, this study aims to perform a thorough investigation to reveal the skid resistance attenuation law of SMA pavement. Multiple types of SMA-13 mixtures prepared by different material designs were selected to conduct a kneading test that simulates real surface states of in-service SMA pavement. Pressure-sensitive film and a 3D laser scanner were utilized for evaluating anti-skid performance and skid durability. The finite element (FE) method is introduced to simulate vehicle braking distance for skid-resistance evaluation. The results show that skid resistance attenuation of SMA pavement consists of two stages: In the first stage, the skid resistance of SMA pavement experiences a short enhancement, followed by a long-term weakening stage. Abundant surface texture of SMA helps to mitigate the impact of traffic load on skid resistance. The FE analysis and pressure-sensitive film results demonstrate the potential of skid durability design of SMA pavement based on the skid resistance attenuation law.

Wax-based additives have been widely used in asphalt pavement for their preferable environmental benefits. However, poor compatibility between wax-based warm mix additives and asphalt easily leads to precipitation of wax and cracking of asphalt pavement. Plasma treatment can effectively modify the surface of various materials. This study applies plasma treatment to improve the surface properties of wax-based additives for compatibility improvement in asphalt binder. Compatibility of two different wax-base additives in asphalt binder before and after surface treatment is investigated via cigar tube test and morphology test. In parallel, rheological properties of wax-modified asphalt are characterized from the perspectives of rotational viscosity, rutting resistance, and fatigue performance. Results show the enhanced surface roughness and chemical activity of wax-based additives after plasma treatment. The adhesion between waxes and the asphalt matrix is significantly improved. Waxes within binder are uniformly dispersed after plasma treatment. The incorporation of surface activated wax helps to promote the viscosity reduction of asphalt binder. Furthermore, the high-temperature performance of wax-based asphalt after surface activation treatment of wax is significantly improved, especially for fatty acid amide waxes. As for fatigue performance, plasma treatment improves the fatigue resistance from a compatibility perspective. Therefore, plasma has great promise for facilitating wax-modified asphalt properties from a compatibility perspective.