The High Speed Railway (HSR) system has been considered as one of the most resource-efficient transport mode that can contribute to the reduction of CO2 emission. China had just over 30,000 kilometers of track in January 2019, which accounted for over 65% of the world's total HSR. Furthermore, over 10 thousand km HSR will be constructed in the following 10 years in China. Considering the construction phase of HSR, is it still environment friendly? When evaluating the carbon emission of the HSR, previous studies often focus on the operation phase. This study estimates the magnitude of CO2 emissions of the HSR in the construction phase using the Life Cycle Assessment (LCA) method. The quantities of materials and the work-time of equipment and machinery used in the construction phase can be obtained based on the budget sheets for sub projects and budget quota of railway engineering. The emission factors of production of materials, production and burning of fuel oil and generating of electricity etc. are obtained from CLCD (Chinese Life Cycle Database) and other researchers. The results show that the emissions from the production of materials contribute to more than 80% of the total CO2 emission during the construction phase. Steel and cement come to the first two main emission sources, account for around 70% of the total CO2 emission. Besides the key materials, the alignment of the HSR should be paid more attention to. Construction of the railway in mountainous area emits much more CO2 than in plain area. Construction of tunnel has a emission intensity about 50 thousand t/km, which is almost twice of the emission from bridge construction and three times of the emission from subgrade construction. The findings could offer decision makers references and better understanding of the carbon emission in construction phase, and help them in the planning and construction phases.

CICTP