Summary

The Minnesota Department of Transportation (MnDOT) partnered with Michigan Technological University (MTU) to host a special environmental product declarations (EPD) workshop specifically for Minnesota producers of construction materials to prepare for recent Federal Buy Clean initiatives. The workshop was held on November 30, 2022 from 1pm to 5pm in the Marriott West Minneapolis. The workshop received an impressive turnout of 40 people, including suppliers, producers, contractors, consultants, state engineers, and representatives from national industry organizations.

The meeting began with Dr. Amlan Mukherjee from MTU welcoming the attendees to the workshop and providing purpose for the importance of the workshop. Workshop participants were seated in breakout teams. The breakout teams were divided with the intent of distributing at least one agency member, consultant, industry association member, and producer / supplier to each team. Dr. Mukherjee informed the participants about federal and local regulations appearing around the United States regarding sustainability of construction materials, federal initiatives that are working towards improving construction materials’ sustainability, and possible upcoming opportunities for demonstration projects. These initiatives and opportunities include the Climate Challenge and Inflation Reduction Act.

Lianna Miller from WAP then provided background detail on sustainability-related terms that industry members will need to be familiar with, including life cycle assessment (LCA), EPDs, and product category rules (PCRs). Miller explained how PCRs are used to standardize the method and data used for performing an EPD. An EPD summarizes a product’s potential to impact the environment communicating the outcomes of a life cycle assessment conducted in conformance with a PCR. An EPD has, on occasion, been compared to a nutritional facts label in how it communicates potential environmental impact information. Global warming potential (GWP) and energy use estimations are currently the environmental impact indicators being used from an EPD. All the other midpoint indicators also contain valuable information for considering localized impacts.

Discussion then ensued about the process of developing PCRs, the standardization of background datasets, and how an EPD may be used by project owners. Representatives of program operators for asphalt and concrete mixtures for North America were present in the room and they informed of their verified software that improves EPD reliability and helps with harmonizing data and methods.

Dr. Tom van Dam from NCE Consulting provided additional context into how EPD requirements are developing in other regions, the typical timeline for specifying EPDs, and how this may affect the industry.

Workshop participants performed an interactive activity in their breakout teams looking at a variety of different industry EPDs and answering the following questions for each EPD:

·        Does the EPD use a functional or declared unit? Where is that information?

·        Where is the scope of the EPD identified?

·        Where is the system boundary of the EPD identified?

·        Where is the information of background datasets provided?

·        Where can you find the material’s GWP?

·        How long is the EPD valid for?

The workshop EPDs are publicly available, and belonged to cement suppliers, concrete ready-mix producers, asphalt producers, and aggregate suppliers.

During the activity, Dr. Mukherjee additionally presented general rules of thumb for industry members regarding construction materials sustainability, such as:

·        Concrete GWP is typically between 200 and 400 kg of CO2 eq per cubic meter, depending highly on the cement content.

·        Ordinary portland cement production generally emits 0.95 kg of CO2 eq per kg of cement.

·        Portland limestone cement production generally emits 0.85 kg of CO2 eq per kg of cement.

·        Asphalt mixture production generally has a GWP in the range of 55 – 65 kg of CO2 eq per short ton.

After the EPD interactive activity, Michelle Cooper from MTU presented on the synergy between concrete sustainability and performance. Additionally, she provided data from field and laboratory mixture designs comparing mechanical performance and durability performance with GWP. No correlation was identified between compressive strength and GWP, while durability performance tended to improve with lower GWP mixture designs (see https://onlinelibrary.wiley.com/doi/10.1002/suco.202200634 for more detail).

Following this presentation, attendees returned to their breakout teams for a second interactive activity. This activity modeled a procurement scenario and asked each team member to consider and discuss their roles in the EPD process while answering the following questions:

·        Where do I see myself fitting into the LCA information flow?

·        What information will I need from other stakeholders to conduct my duties?

·        What information will I need to provide to other stakeholders to conduct my duties?

·        What is my current level of preparedness and what support do I need to be fully prepared?

At the end of this activity, each team was given the opportunity to share main takeaways and discussion points from within their group. These concepts included:

·        Concerns:

o   That designers on the front end of a project not knowing a lot of the construction stage information that may change the GWP.

o   About whether incentives and pay factors would be involved.

o   For the amount of reporting and compliance checking that contractors and local DOTs may need to perform.

o   Regarding how mobile batch plants will be affected.

o   How industry can utilize funding from the Inflation Reduction Act.

o   Need for clarity on how the construction phase aspects work for an EPD. What needs to be included? To how much detail? What about when construction scheduling and staging changes?

o   How utilization of EPDs will look: materials and plans for construction that change between procurement and installation phases of a project.

o   Need for harmony in EPD requirements across regions and states to facilitate transport of materials across state lines. For example, there are no cement producers in Minnesota or Wisconsin, so they get material shipped from other states. How might this impact the industry if EPD requirements are vary by state, particularly in scope?

o   Need to consider flexibility of the requirements and tasks to the end user.

o   Mixture designs are tweaked on the fly. At what point in changes to the mixture design is an EPD out of tolerance or out of conformance?

·        Lessons / Realizations:

o   That until we have GWP values from many industry EPDs in the region, we will have more questions than answers. We may need several years of data to get a baseline number and understanding of project GWPs.

o   That there will be a lot of values to track that must be input to EPDs. This generated discussion about possibly using an e-ticketing system to simplify the data collection and tracking process.

o   Recognition that all members of the industry but be on board for EPDs to be successfully developed and utilized.

o   Many aspects of the EPD will need to be provided by the general contractor, and many aspects of the EPD will also need to be provided to the general contractor.

o   Understanding the exact scope of an EPD is essential.

o   How to evaluate products that are reused on site.

·        Possibilities / Ideas:

o   Specification relief.

o   It may be beneficial to institute a minimum project size that is affected by EPD requirements. The amount of effort and cost associated with developing an EPD may not be worthwhile for small projects such as a 20ft sidewalk.

Dr. Van Dam identified clinker reduction as the main lever to pull in reducing GWP. Dr. Van Dam then presented a short discussion on the industry’s concrete mixture overdesign and the inconsistencies in cement content requirements throughout the United States, even between regions with similar climates.