In recent years, the greenhouse effect has become a major challenge for
sustainable development, with carbon dioxide emissions playing a significant
role. In 2022, China’s carbon dioxide emissions reached 12,667,430 tons [1], the highest globally, with the
transportation sector contributing about 8% of this, and road transportation
accounting for 90% of the sector’s emissions. To promote green development, the
Chinese government emphasizes efficient resource use, energy conservation, and
emissions reduction, aiming to build a strong transport system by 2035.
Understanding carbon emissions in expressway construction is crucial for green
development. Studies on highway carbon emissions focus on emissions from road
construction and vehicle operation. For example, Chen et al. used a “bottom-up”
method to account for emissions during construction, while Tu et al. created a
vehicle carbon emission model during operation. With the expanding highway
network, maintenance has become essential, but carbon emissions from highway
maintenance are often overlooked. Lu et al. divided emissions into material
production, transportation, and construction stages, calculating the total
emissions from these factors. Yang Yuanyuan et al. divided emissions into six
parts and proposed maintenance methods for different conditions. Zheng et al.
used a life-cycle approach to assess maintenance carbon emissions and compared
methods to identify the least carbon-intensive option. Zhang added congestion
and detour emissions to the transportation stage. This paper divides highway
construction emissions into four categories: construction machinery, material
transportation, construction materials, and recycled materials. It calculates
emissions for each stage separately, making the method applicable to all types
of expressways. The results of these calculations will contribute to assessing
carbon reduction measures in expressway projects.