Project uses bio-oil to improve conditions of pavements

Ben Theobald

Cold, December weather often freezes sidewalks and damages asphalt on paths and streets.

Christopher Williams, associate professor of civil, construction and environmental engineering, is head of a project that is testing bio-oil on asphalt in order to improve hot and cold weather performance of pavements. Williams has been working on the project for four years.

“We fractionate the bio-oil in five or six different fractions,” Williams said. “Those different fractions have different compositions.”

Williams and a research group have been working to test their data.

“We produced asphalt that we heated up in a high temperature,” Williams said.

The asphalt goes through a treatment process to ensure no water is in the asphalt once it is made.

“Two fractions that come out of the bio-oil are put through a heat treatment, which dries out the water,” Williams said. “Then blend it in with asphalt or we can take a polyethylene, which stabilizes and provides low-temperature cracking.”

An alternative to the heat treatment process is to use petroleum as a replacement for the asphalt. These studies have been conducted in a lab to see if they are able to replace asphalt.

Petroleum is another alternative. It can be used either as a partial replacement or a full replacement for the asphalt, Williams said.

Williams and his group will receive a sub-award through the Power Fund Project. Avello Bioenergy Inc. who Williams is working with, received a $2.5 million grant to develop bioasphalt as well as other bioproducts.

The current price of asphalt is about $400 per ton, or 2,000 pounds.

“Bio-asphalt can be produced at a lesser price,” Williams said. “Asphalt comes from crude petroleum. If we as a country want to be more energy dependent, it means we’re going to have less asphalt available.”

In the United States, 90 percent of paved roads utilize asphalt.

“Asphalt is a maintenance application for sealing cracks and making more quality roadways,” Williams said.

Since asphalt is what helps build our roadways, it, of course, is an important element of creating a way for transportation services, which are heavily dependent on roadway systems.

“Around 65 to 68 percent of our [gross domestic product] relies on our transportation systems,” Williams said. “Vast majority is highway-based.”

Williams hopes to use bio-asphalt material as a way to create more jobs as well as a way for paving a way to a cleaner environment.

“It helps create a cleaner environment, and we become less dependent on foreign energy sources like petroleum,” Williams said.