Effect of Methodological Choices on Pavement Life-Cycle Assessment

The use of life-cycle assessment (LCA) to assess the environmental impacts of pavement systems has become more prevalent in recent years. When performing an LCA study, a series of methodological choices must be defined. As these decisions can change from study to study, it is important to understand the significance or insignificance of the methodological choices relevant to pavement LCA. This paper evaluated the sensitivity of five choices commonly made in pavement LCA; cut-off criteria, end-of-life (EOL) allocation, asphalt binder allocation, traffic growth, and type of energy reported. Eight case studies and four environmental indicators, that is, global warming potential, primary energy as fuel, total primary energy, and a unitless single score, were considered in the sensitivity analyses. Varying the cut-off criteria and asphalt binder allocation only had a significant impact on the environmental indicators when the use stage of the life-cycle is excluded and only the materials and construction, maintenance and rehabilitation, and EOL stages are considered. Using different EOL allocations, traffic growths, and types of energy reported had significant effects on the overall life-cycle results. Common methodological choices made in a pavement LCA are expected to have an impact on LCA results and subsequent interpretation, with the magnitude of the impact dependent on the scope of the analysis.