H.C. part of research project

Howard County - The most heavily-traveled gravel road in Howard County is now part of a research project under the Iowa Research Board and Iowa State University. 

A one-mile stretch of 100th St. between Pine and Quail on the Howard-Chickasaw County Line is the guinea pig! About half that section of road was given seven different surfaces, so researchers could analyse the wear-and-tear, maintenance and initial cost over a 2-3 year term.

The road was chosen since it is heavily used by Reicks View Farms. The project began this past August. Howard County Engineer Nick Rissman said a road in Cherokee County was also used in the project.

• One 500-foot section that was removed after just a few days was the ground rubber tire base with road rock surface. Rissman noted a person could feel the “give” in the surface just walking across it. With heavy trucks traveling the road, it would not have withstood heavy traffic.

• Another 500-foot section was labeled Optimized Gradation with Compaction and Moisture Control. That process consisted of bringing in new road rock and adding clay slurry, a clay mixture.

• Recycled Asphalt Pavement (RAP) was mixed with road rock for another 500 feet.

• Two different slag companies (Harsco and Phoenix) were used. Slag is a by-product from making steel. Each company had 500 feet with half of each installing the material for either two or four-inch depths.

• The last section took the most time for employees of secondary roads to complete. For 500 foot Aggregate Columns section, every 10 feet, a hole was augered down seven feet. It was filled with clean concrete stone, which will allow water to flow through frost. 

Rissman said one of the biggest reasons different road types are being researched is because of the cost to pave a gravel road. “Paving a road that has never been paved costs about three-quarters of a million dollars per mile. To repave a road costs about $300,000 per mile.”

Through this research program, Howard County got some material for free, but had to pay for hauling it from the Davenport area.

“We probably won’t know how well the different sections work for a couple years. They will have to go through several freeze/thaw periods. We’ll also have to keep track of how much maintenance needs to be done,” Rissman explained. 

A couple employees have a book, and any time they drive or do maintenance on that one-mile stretch, he or she needs to write down what they are observing. Each section of the road is marked, so employees can tell the difference.

So far, on some of the special sections, Rissman said they have observed less than typical maintenance.

The good part of this research project is ISU is trying to find a solution for counties who have heavily-traveled roads. In addition, they are finding ways for counties to use their own manpower to accomplish the work.

It will be several years before the technology can be utilized, but it may help some counties find a different way to save their infrastructure.