Abstract: This research work is concerned with the life cycle
assessment (LCA) of an expressway, as well as its infrastructure, in
Thailand. The life cycle of an expressway encompasses the raw
material acquisition phase, the construction phase, the use or service
phase, the rehabilitation phase, and finally the demolition and
disposal phase. The LCA in this research was carried out using CML
baseline 2000 and in accordance with the ISO 14040 standard. A
functional unit refers to transportation of one person over one
kilometer of a 3-lane expressway with a 50-year lifetime. This
research has revealed that the construction phase produced the largest
proportion of the environmental impact (81.46%), followed by the
service, rehabilitation, demolition and disposal phases and
transportation at 11.97%, 3.72% 0.33% and 2.52%, respectively. For
the expressway under study, the total carbon footprint over its
lifetime is equivalent to 245,639 tons CO2-eq per 1 kilometer
functional unit, with the phases of construction, service,
rehabilitation, demolition and disposal and transportation
contributing 153,690; 73,773; 3693, 755 and 13,728 tons CO2-eq,
respectively. The findings could be adopted as a benchmark against
which the environmental impacts of future similar projects can be
measured.