Economic and environmental assessment of the Korea urban railway and its greenhouse gas mitigation potential

Railways can simultaneously transport large quantities of freight and passengers, making them energy-efficient and economical modes of transportation. Changing the materials that constitute a significant portion of rail track systems can help mitigate climate change. Gravel and concrete trackbed methods are commonly employed in railway construction. This study proposes the utilization of the asphalt concrete trackbed method, which is currently being researched and developed in South Korea, in addition to traditional gravel and cement concrete methods, and presents its economic feasibility and environmental benefits. The asphalt concrete trackbed method, which has already been implemented in regions such as China, Australia, and Europe, can also be applied in other areas. This study analyzed the carbon emissions and economic feasibility in the construction, usage, and disposal stages of cement concrete and asphalt concrete trackbeds. Previous research on carbon emissions analysis has faced challenges in applying geographical and climatic, as well as energy sources, to individual cases in the context of construction in Korea. Using the Korean Life Cycle Inventory database, this study indicated that asphalt concrete exhibits approximately 2.65-times lower carbon emissions than cement concrete. In Korea, railway construction involves 1,998 tons of asphalt concrete mixture, 1,820 cubic meters of cement concrete, and 59 tons of rebar per kilometer. Furthermore, the asphalt concrete trackbed method shows potential cost savings of approximately 29,000 EUR when converted to the 2021 EAU value. Thus, asphalt concrete trackbeds not only provide environmental benefits, they are also economically viable. However, further research is required to establish precise standards for on-site construction. This study is expected to provide foundational data for promoting the widespread adoption of asphalt concrete trackbeds in areas that produce asphalt concrete.