Development of life cycle assessment tool for pavement sustainability analysis

Motivated by the emerging importance of sustainability in transportation infrastructure, this study aims at developing a Life Cycle Assessment (LCA) tool to quantify the energy and environmental impacts of pavements. The general LCA framework is incorporated into a highly customizable Excel-based software tool that can be used to facilitate environmental assessment of pavements at the project-level. The impact assessment focuses on the cumulative energy demand (CED) and greenhouse gas (GHG) emission in the material, construction, and maintenance phases of pavement life-cycle. LCA results are highly dependent on the quality and appropriateness of data in the life cycle inventory. Therefore, different inventory database from major pertinent studies were reviewed and summarized. To implement the LCA framework, case studies regarding runway pavement rehabilitation/reconstruction at the John F. Kennedy (JFK) airport and new runway pavement designs conducted using the Federal Aviation Administration (FAA) pavement design methodology were conducted. Life-cycle inventory data were compiled from literature and field surveys from contractors. The data variations in the material-related energy and emission rates were considered for sensitivity analysis. Both direct energy consumption and GHG emission and their corresponding upstream components related to process fuels were considered in the impact assessment. The results indicate that the expected pavement service life and maintenance treatments significantly affect the comparison between hot-mix asphalt (HMA) and Portland cement concrete (PCC) pavements. The consideration of energy and emissions associated with the production of process fuels and electricity in the upstream process cannot be neglected in the LCA. The analysis findings suggest that there are no general conclusions on pavement type selection for sustainability and the project-level analysis need be conducted for selecting the most appropriate design alternatives.M.S.Includes bibliographical referencesby Chinmay Thakka