Environmental Impact Analysis of Pavement Maintenance Using Life-Cycle Assessment and Microsimulation

Life cycle assessment (LCA) is being accepted by the road industry to measure such key environmental impacts as the energy and CO2 footprint of its materials and laying processes. Previous life cycle studies have indicated that the traffic vehicles account for the majority of energy consumption and emissions from a road. Contractors and road agencies are therefore looking for road maintenance works that have overall the least environmental impacts considering both the roadwork itself and the disturbed traffic. This paper reviews relevant LCA studies worldwide; and describes the development of a LCA model for pavement construction and maintenance. The model is applied to an asphalt road rehabilitation project in the United Kingdom (UK), where micro-simulation model VISSIM is used to depict the traffic on it meanwhile. The results are fed to traffic emissions model EnvPro, and emissions from the roadwork and the traffic are compared. It is found that the additional fuel consumption and emissions by the traffic during the roadwork is significant. This calls for in the future an effective traffic management amid road maintenance works. The LCA model can be further tested and calibrated as a decision support tool for sustainable construction in the road industry.