Midwest Transportation Center

About the research

Given that an ever-increasing number of state Departments of Transportation (DOTs) across the nation are exploring the use of Environmental Product Declarations (EPDs) as a means to quantify the embodied environmental impacts and emissions of their pavements (either as a result of “buy-clean” legislative mandates or executive policy), the Iowa DOT would benefit from better understanding what is involved with requiring contractors to produce EPDs associated with a concrete paving project, and how that information can be best used to inform improved decision-making in the sustainability and carbon emissions context. Additionally, the Iowa DOT aims to better understand how the embodied-impacts-only analysis (reflected through EPDs) compares to a whole life-cycle analysis (established via a full life cycle assessment, or LCA).

To meet these objectives, the Iowa DOT proposes to identify a concrete paving project (2023/24 construction season) where materials, production, and construction activities can be carefully monitored in order to collect the necessary information and data to develop EPDs consistent with current product category rules (PCRs). It is anticipated that adjustments in the prescribed process required by the relevant PCR will be necessary as the current PCR for concrete is tailored to ready-mixed concrete, and not concrete produced at a portable plant. This research will help establish what type of adjustments will be necessary to adequately capture portable plants as well. All information will be gathered in accordance with requirements consistent with a Type III EPD as defined by the International Standards Organization (ISO). The goal in collecting this information and developing the relevant EPDs is to enable Iowa DOT and in turn the Iowa paving industry to better understand the level of effort required (by both agency and industry) to generate EPDs for paving concrete, and identify areas where improvements in data collection, education and training are needed to facilitate possible routine EPD generation in the future.

This information will also inform a benchmarking analysis of current Iowa DOT concrete paving operations. In addition, Iowa DOT proposes to conduct additional analysis of lifecycle greenhouse gas (GHG) emissions (using LCA), including such use-phase impacts as pavement-vehicle interaction, albedo and carbonation, and suggestions on how to further reduce pavement related lifecycle GHGs emissions. The objectives of these additional analyses are to enhance the Iowa DOT’s understanding of the complete life cycle impacts associated with pavement assets, and inform improved decision-making in the pavement arena to lower the GHG emissions associated with Iowa’s pavement assets.