Readily Implementable Strategies for Reducing Embodied Environmental Impacts of Concrete Pavements in the United States

Abstract

This study evaluates strategies that agencies can implement to reduce the embodied carbon of paving concrete to support decarbonization efforts in the concrete industry and transportation sector. First, key decarbonization measures reported in the literature were investigated with regard to the decarbonization hierarchy, agencies’ decision-making authority, time, and economic considerations. Second, the state of the practice in concrete paving was benchmarked by evaluating the main-lane paving concrete mixtures collected by the Federal Highway Administration’s Mobile Concrete Technology Center using lifecycle assessment (LCA). The analyzed dataset included 27 projects across the United States between 2011 and 2019. Lastly, the opportunities for embodied carbon reduction were identified for the analyzed dataset, and readily implementable savings were calculated. The results indicate that the most significant and available opportunity for embodied carbon footprint reduction is avoiding mixture overdesign by lowering the cement content. The use of supplementary cementitious materials is another beneficial practice for carbon footprint reduction; however, the results indicate that this practice is already common. Because cement contributes to 73%–93% of the concrete carbon footprint, cement production’s plant- and product-specific footprint is a critical priority. Mixture design optimization aided by the appropriate specifications and consistent environmental reporting can synergize the decarbonization efforts of agencies and the industry. Lastly, this study demonstrates the use of LCA to help agencies make data-driven decisions and evaluate context-specific strategies to reduce their embodied environmental impacts.