The EPA Answers Your Questions About Asphalt EPDs

Over the last few years, the genesis of the environmental product declaration (EPD) within the asphalt industry, as well as its continued rise in importance for producer and pavers who work on Federal and State infrastructure projects. However, outside of the meetups organized by the National Asphalt Pavement Association (NAPA), there are still a lot of questions on contractor’s minds about how the EPDs function, how they are best utilized, as well as a myriad of other unknowns. 

We reached out to the source, in order to provide some answers about EPDs, low embodied carbon materials, and how their impact my effect contractors.

Previously, Joseph Shacat was the Director of Sustainable Pavements at the NAPA, and then last year he moved into a position as Special Advisor for Implementation at the Environmental Protection Agency (EPA), taking his expertise, and his many years of field knowledge into the federal government, to help shape the sustainable future of the industry. The answers to the question below are his, as approved by the EPA Office of Media Relations and Risk Communications.

Q: If you’re an asphalt producer, how do you start making mixes that qualify as a low embodied carbon material? What is required to achieve that status?  

There are a variety of programs and policies at the local, state, and federal level related to embodied carbon. Some are focused on disclosure, in which case a producer would only need to provide an environmental product declaration (EPD) to meet the requirements of the project owner (e.g. the state, county or city Department of Transportation, the building owner, the project developer).

In other cases, the EPD would need to meet the project owner’s established embodied carbon thresholds under a given policy. 

An EPD is the document that quantifies the embodied carbon (quantified as the global warming potential or GWP) and other environmental impacts associated with manufacturing a product. EPA provides a variety of resources to support manufacturers as they develop EPDs, summarized here: https://www.epa.gov/greenerproducts/technical-assistance.  

For asphalt mixtures, EPDs include processes such as extracting and manufacturing raw materials (asphalt binder, aggregates and other materials), transporting raw materials to an asphalt plant and plant operations. Collectively, these are referred to as the cradle-to-gate stages of a product’s life cycle.  

Q: What factors determine a mix design’s environmental status?  

There are a variety of factors that impact the embodied carbon associated with an asphalt mix, not just the mix design.

Broken down by life cycle stages:  

• In the raw material manufacturing stage (referred to as the A1 life cycle stage in an EPD), the most significant factor is the virgin asphalt binder content. Mixes with higher recycled material contents tend to have lower embodied carbon. Aggregate quality is also a factor in the asphalt binder content – a less absorptive rock could help reduce embodied carbon by reducing the virgin binder content as compared to a more absorptive aggregate. It’s also important to note that modified binders have higher embodied carbon content than neat binders. Many embodied carbon policies account for this by establishing separate thresholds or limits for mixes with modified binders. Also, hydrated lime used in the mix can also contribute significantly to a mix’s embodied carbon. Liquid anti-strips can be a suitable low-carbon alternative when they are allowed by the project specifications.  

• In the transportation stage (referred to as the A2 life cycle stage in an EPD), the most significant aspect is usually the aggregate haul distance. You might consider locally sourced materials to reduce a mix’s embodied carbon. Another approach is to use a more efficient transportation mode. Rail and barge, when available, will have significantly lower embodied carbon than truck transport.  
• The most significant aspects of mix production (referred to as the A3 life cycle stage in an EPD) are the plant’s energy efficiency and the type of burner fuel consumed. Energy efficiency can be improved through aggregate moisture management, use of warm mix technologies to reduce mix production temperature, and a variety of other factors. Lower carbon fuels, such as natural gas, can significantly reduce a mix’s embodied carbon content.

An excellent resource for mix producers is the ENERGY STAR APEX program (https://www.energystar.gov/industrial_plants/industrialfocus/asphalt_pavement_production), a free program that helps asphalt mix producers manage and reduce energy consumption.    

Q: For those on the paving side, if they’re looking to buy asphalt mixes that qualify as LEC for a road project, how do they ensure the mix design meets the requirements? 

Paving contractors who purchase asphalt mix from a third-party supplier need to confirm the supplier is able to provide an EPD for the mix. They would then need to check the EPD against the project owner’s embodied carbon policy to make sure it meets the project requirements.  

Getting a supplier to provide an EPD may require further negotiation, especially if they have not already developed or published EPDs for the plant that will supply the job. There is a cost to developing EPDs, so that’s another factor to be mindful of as part of the negotiation.

As with any aspect of meeting an owner’s project requirements, paving contractors should review and revise contract language to make sure all expectations are agreed upon by both parties.  

There is also a timing consideration. If the supplier has not already developed EPDs, it could take several months to take the necessary training and gather the data needed. If the EPD does not meet the project’s embodied carbon thresholds, paving contractors may need to work with the supplier to identify alternative mix designs, or even find other asphalt plants nearby that meet the owner’s specifications. 

Q: Are there any special forms or other documentation needs that must be completed for a project using LEC materials? 

In most cases, the primary document is the EPD. Contractors should always check the project specifications for any additional requirements. 

Q: What sort of federal grants/funding projects are available to contractors who utilize LEC materials? What incentives exist out there for them to go through the added efforts? 

There are numerous federal programs to help contractors develop EPDs and meet the demand for low embodied carbon materials.  

EPA’s C-MORE Program (Construction Material Opportunities to Reduce Emissions) has a variety of resources to support EPD development, including technical assistance, grants and the low embodied carbon label program.

EPA’s direct advisory services offer a way for companies to contact EPA directly for help with EPD development and other related activities.  

Federal agencies are already purchasing low embodied carbon construction materials. The General Services Administration (GSA) has announced over 160 projects that will use low embodied carbon materials under its low embodied carbon program. The U.S. Department of Transportation’s Federal Highway Administration (FHWA) has recently announced $1.2 billion in funding to 39 state DOTs under its Low-Carbon Transportation Materials Grants Program. And the Federal Emergency Management Administration (FEMA) has developed a program that allows agencies to purchase low embodied carbon materials for disaster recovery projects. 

Q: Is there anything important about the process of certifying LEC materials or documenting their use that contractors should know about, that we haven’t covered elsewhere? 

This is a rapidly evolving space, with lots of opportunities for asphalt mix producers, material suppliers, and paving contractors to access the market for low embodied carbon construction materials; and create value for their customers who want to purchase these products. EPA’s C-MORE program will provide updates as it continues to develop its label program for low embodied carbon construction materials to help manufacturers and purchasers navigate this growing marketplace.