Man laying asphalt
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Colorado approves law requiring greenhouse gas transparency for asphalt road construction

The state is the first to require greenhouse gas data on the asphalt being used to construct roads.

Colorado lawmakers recently approved legislation that could affect the construction of asphalt roads. Called the Buy Clean Colorado Act, the law requires contractors to submit data that shows the environmental impact of the asphalt mixes being used on road and bridge projects.

The bill affects projects advertised beginning July 1, 2022, by the Colorado Department of Transportation (CDOT). The bill requires asphalt mixes and other affected materials to have an environmental product declaration (EPD) assigned to them. EPDs are reports used to help assess the environmental performance or impact of a product or material over its lifetime.

Shacat says the EPD label is like a nutrition label found on food packaging. However, Shacat says that the industry won’t know how this legislation affects construction material costs until the actual policies and global warming potential (GWP) limits are established by the Colorado Department of Transportation and the Office of the State Architect.

“Initially, asphalt mix producers and other material suppliers who are affected by Colorado’s new requirements will have to develop EPDs,” says Joseph Shacat, National Asphalt Pavement Association (NAPA) director of sustainable pavements. “For asphalt mixtures, this process is straightforward and inexpensive using NAPA’s Emerald Eco-Label software.”

The law also applies to projects like parking lots and cement garages. Products like cement and concrete mixtures, glass, steel and wood structural elements are also required to have EPDs. 

Shacat believes this legislation could increase the use of reclaimed asphalt pavement (RAP) and recycled asphalt shingled (RAS) in the state. According to the annual NAPA/ Federal Highway Administration (FHWA) Industry Survey on Recycled Materials and Warm-Mix Asphalt Usage, the average RAP content for asphalt mixtures produced in Colorado is 20 percent, which is just below the national average of 21.1 percent. The industry survey indicates an estimated 1.3 million tons of RAP are stockpiled in Colorado, but the use of RAP and RAS is generally limited by agency specifications, Shacat says.

“This could be an opportunity for the asphalt paving industry to work with agency officials to revise specifications in a manner that enables the use of innovative technologies and materials to meet the new requirements,” Shacat says.

The main greenhouse gas producers in the construction of asphalt roads are typically related to burner fuel consumption in drying aggregates, asphalt binder content and hauling aggregate, Shacat told Equipment World, a publication focused on construction equipment.

As the CDOT collects EPDs for its construction projects, it will use the data to formulate a policy by 2025 to reduce greenhouse gases, according to NAPA. For building construction, the Office of the State Architect will establish a procurement policy in 2024 that uses EPDs to determine compliance with greenhouse gas emission limits for each material, reports Equipment World.

President Biden and his administration have been discussing implementing EPDs for federal projects like military bases. On top of that, the CLEAN Future Act was recently introduced in the U.S. House of Representatives, which would require EPDs on materials for federal projects and call for net-zero greenhouse gas pollution by 2050.