Life-cycle CO₂ emissions and influential factors for asphalt highway construction and maintenance activities in China

ABSTRACT

This study tried to clarify the magnitude of CO₂ emissions from highway construction and maintenance in China through life cycle assessment (LCA) method. For this, 227 real highway projects constructed from the year 2000 to 2011 in Zhejiang Province, China are classified into six types by two categories of N road (62 projects without grand bridge, great bridge and tunnel) and Y road (165 projects with the same road structures) and three sub-categories of (i) newly constructed road, (ii) replacing pavement road and (iii) full rehabilitated road. Significant influential factors of LCA results were revealed through multivariate linear regression models, combined with data quality assessment and sensitivity analysis. Numerical interval of assessment results indicate that the construction emissions of N highway project are more centralized to no more than 2900 t/lane-km, while Y project have a normal upper boundary of construction CO₂ emissions, about 5000 t/lane-km. The contribution of maintenance to CO₂ emissions probably could exceed that of newly construction both for Y project and N project. In addition, the pavement replacing and rehabilitation could bring about large amount of CO₂ emissions which even match with the CO₂ emissions from cumulative traffic volume during highway's life cycle. There are common factors for six categories. Cement and steel are the top largest CO₂ emissions contributors and sensitive factors for N road and Y road. The LCA results are not sensitive to the local construction materials but sensitive to the emission factor of diesel used in transportation and on-site construction.

KEYWORDS:

• Life cycle assessment
• CO₂ emissions
• asphalt pavement
• construction
• maintenance

Acknowledgements

The authors thank for the financial support by National Natural Science Foundation of China (No. 51178055), Fundamental Research Funds for the Central Universities of China (No. 310821171003) , the Special Fund for Basic Scientific Research Funds of Central Universities of Chang'an University (No. 310821175025) and Chinese Scholarship Council (No. [2017]3109).

Additional information

Funding

National Natural Science Foundation of China 51178055; Fundamental Research Funds for the Central Universities of China 310821171003; the Special Fund for Basic Scientific Research Funds of Central Universities of Chang'an University 310821175025; Chinese Scholarship Council [2017]3109