Iowa State pavement expert: Buckle up, pothole season in Iowa is just beginning

AMES, Iowa - You've held your breath and grimaced as your car bounced over another big pothole. Iowans are probably going to have to get used to it, says an Iowa State University pavement expert.

"You better buckle yourself in," said Christopher Williams, an associate professor of civil, construction and environmental engineering and the manager of the Asphalt Materials and Pavements Program at Iowa State's Institute for Transportation. "This spring will surely be getting worse. As we move toward mid-March, it will be above freezing during the day and below freezing at night. And with all the snow and water out there, our transportation infrastructure will take a bigger beating."

Williams said the culprits are freeze-thaw cycles, wave after wave of snow, pavements that are decades old and traffic loads that are heavier than many roads were designed to carry.

This time of year, when snowmelt seeps through pavement joints and cracks during the day, the water pools on top of the frost below. Williams said that water freezes and expands at night, creating ice lenses that lift and crack the pavement. Heavy traffic loads hit the distressed pavement and before long you're running an obstacle course of potholes.

But there's hope for better springs ahead.

Williams' research agenda includes finding asphalt materials that resist moisture damage and can do a better job withstanding freeze-thaw cycles. He's also looking for ways to improve Iowa's pavement design standards with the idea of extending pavement life while making construction more cost effective.

And he's working with Gene Takle, an Iowa State professor of geological and atmospheric sciences and agronomy, to study how climate change could impact Iowa's roadways. The data indicate Iowans could see more and more freeze-thaw cycles. That's going to challenge engineers to come up with even better pavements and road designs.

While they're at it, Williams said engineers need to find ways to contain costs. He said today's reality is that state and federal funding for road and highway projects is stretching thin.

And so Williams is keeping busy in his campus lab. His work could be a key to smoother roads ahead.

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