Life Cycle Assessment of Concrete Overlay Strategies

The development and maturation of concrete overlays in recent decades has provided a useful new pavement rehabilitation option to agencies in the US and around the world. Concrete overlays can be designed for nearly all existing pavement types and conditions and can fulfill both short- and long-term service life objectives. Increasingly, agencies are prioritizing and incorporating sustainability into planning and decision-making processes. For concrete overlays to continue to serve as a useful rehabilitation treatment in the future, it will be necessary to quantify the life cycle greenhouse gas emissions of different concrete overlay design strategies. This study identified four representative concrete overlay projects constructed in Iowa between 2009 and 2022 for use as case studies. These projects include concrete on concrete overlays and concrete on asphalt overlays that serve relatively lower and relatively higher traffic levels. Life cycle assessments were performed on each of the case studies, as well as alternative design concepts developed for each project, to determine the sensitivity of life cycle global warming potential of concrete overlays to design life, bonding condition, and traffic level. The results of this analysis can inform agencies how concrete overlays can be used and optimized to improve the sustainability of their roadway network.