New life may be given to old tires thanks to the research efforts of two Iowa State professors.

ISU civil engineering professors Robert Lohnes and Bruce Kjartanson are co-principal investigators in a research project that makes use of old tires for subsurface drainage systems.

Currently, a subsurface drainage system is built by digging a trench, filling it with sand and gravel and topping it with soil.

Dodger Enterprises, a company in Fort Dodge, Iowa, built a prototype that uses shredded tires instead of sand and gravel at the bottom of a trench. Field work by Dodger Enterprises proved that this concept worked, Kjartanson said.

Kjartanson said Dodger Enterprises came up with a “fairly unique and innovative” idea of looking into the initial development of this type of drainage system.

“We are basically quantifying their ideas,” he said. He said the ISU team, led by Kjartanson and Lohnes, measured how shredded waste tires perform as fill and how whole truck tires perform as culverts to help lower the water table.

The ISU team “is testing the performance data for design, and to ensure the performance of the drainage structures,” Kjartanson said. The research results will be used to design guidelines so other people will know how to build these types of drainage structures, he said.

The ISU team consists of graduate research assistants Megan Gebhardt, Shiping Yang and Peter Zimmerman, and undergraduate assistant Chris Kruse.

Iowa landfills and dumps accumulate 3 million used tires per year and are continuing to grow, Kjartanson said. “A subsurface gallery, (a drainage trench), will use 6,000 passenger tires per 100 feet,” he said. This will “significantly” reduce the number of used tire stockpiles in Iowa and the United States.

By using tires for fills and culverts in drainage systems, “we are reusing an otherwise waste material that is just being discarded in uncontrolled and controlled dumps,” Kjartanson said.

Another added benefit of making use of old tires in this way is that tires are more economical and cost effective than the usual metal and concrete culverts and sand and gravel fill.

Funding for this research project has been provided by the Landfill Alternatives Grant Program of the Iowa Department of Natural Resources, the Recycling and Reuse Technology Transfer Center, Dodger Enterprises and the Research Initiation Award (RIA), which is a research grant from ISU.

Kjartanson said the research at the Town Engineering building actually started in January of this year. “In two years we should be pulling design standards together with Dodger Enterprises and publishing reports,” he said.