Materials Program tours asphalt emulsion plant in Cheyenne

By Mark Horan

On April 18, around 25 WYDOT staff spent a snowy afternoon touring the Ergon Asphalt and Emulsions Plant in Cheyenne. The majority of the group were from the Materials Program. They were joined by Assistant Chief Engineer for Engineering and Planning Keith Fulton and several Cheyenne resident engineers and their crews.

According to the Asphalt Institute, asphalt emulsion is “liquid asphalt cement emulsified in water.” It is a combination of three basic ingredients: asphalt, water and a small amount of emulsifying agent.

At the Ergon plant, the components are introduced into a colloid mill that shears the asphalt into very small droplets. The emulsifier keeps the asphalt droplets in a stable suspension. The result is an asphalt-based binding agent with a consistency ranging from that of milk to that of heavy cream, which can be used in cold processes for road construction and maintenance, such as chip sealing and slurry surfacing.

“WYDOT specifies multiple grades and types of asphalt binder on WYDOT projects” said State Materials Engineer Greg Milburn. “Understanding the difference in chemistry and how that affects performance is important.”

According to Milburn, it’s valuable for WYDOT field inspectors to be aware of best practices for handling binder so they know when a binder’s quality can be compromised.

“It was definitely a worthwhile experience for us to go out and tour the plant,” Milburn said. “We learned a lot and it was a great team-building opportunity.”

Ergon Asphalt & Emulsions is one of seven companies approved to supply asphalt-derived products on WYDOT projects. WYDOT has used Ergon’s products for over a decade.

In fiscal year 2022, WYDOT had nearly 50 projects that contained asphalt products such as the kind produced at Ergon. The approximate value of these products was well over $90 million.