Concrete samples from Iowa highways can be found on top of Science I this week.

Paul Spry, professor of geological and atmospheric sciences, along with Robert Cody, affiliate associate professor emeritus of geological and atmospheric sciences, and three graduate students are working on a project to increase the longevity of roads.

One mile of highway costs approximately $1 million.

An increase in the life of the highway concrete could “save the taxpayers a lot of money,” Spry said.

The goal of the team’s current research project is to find ways to limit the growth of the mineral ettringite, which causes cracking in the concrete and leads to premature destruction of highways.

Ettringite normally develops to a certain point in highways, but it grows to a destructive level when de-icing chemicals are applied during winters on the roadways, Spry said.

The mineral causes deterioration to occur between the aggregate and the cement, and within the cement itself.

The group is looking to add an inhibitor to the de-icing chemicals applied on the roads.

With this inhibitor, Spry said, “We may be able to control deterioration in highways.”

The research team will be testing the de-icing salt solutions with the added inhibitor on highways during the upcoming weeks.

“We’ve been one of the few groups who have actually done testing,” Spry said.

One of the difficulties related to the research involves the $142,000 Iowa Department of Transportation grant. It only lasts for two years, Spry said.

In studying the life span of roads a longer time frame is needed.

The team will use greater amounts of the salt solution on the highway samples atop Science I to speed up the researching process. The rooftop samples will also help to simulate the cold and hot temperatures found in Iowa.

The samples are taken from five- to 10-year-old Iowa highways.

Spry and Cody have been working on highway issues for a decade.

Their earlier research, assisted by Anita Cody, affiliate instructor of geological and atmospheric sciences, focused on finding the least harmful salt solution that could be applied during the winter.

The group found that minerals were growing in the spaces within the concrete, causing cracking.

The most recent project focuses on the single mineral ettringite. This project is also unique because they will be testing their research in real-life settings.

“[Deterioration] is definitely a national problem,” Spry said.

Roads that have a desired life span of forty years are showing signs of deterioration after just five years, he said.

Dena Gray-Fisher, media relations officer for the Iowa Department of Transportation, said the DOT’s use of a salt solution with an inhibitor in the future would depend on a lot of things, including the cost to make the mixture and the overall benefits of the solution.