Visitors to the Farm Progress Show in Boone, will notice a new addition underfoot; as part of a research project to test pavement strategies, the streets in the show site have been paved. The project, a joint effort of Boone County, the Iowa Department of Transportation and Iowa State University, can help create less expensive and longer lasting highways.
"The road stabilization and paving project at the Central Iowa Expo Site was a huge step to making the Central Iowa Expo Site a show place for people from all over the world to come and look at the latest innovations in the farming industry," says Scott Kruse, assistant Boone County engineer.
The site is a valuable resource for many reasons regarding pavement research; it provided a site without traffic to allow further testing after pavement had been completed, and with the roads equipped with sensors to monitor stresses, the many types of agricultural equipment brought to the Farm Progress Show can help bring diverse readings to the sensors' data.
This year is the third summer of the project, with the subgrade being completed two years ago and paving completed last summer, says Mark Dunn, Iowa DOT operations research engineer. Dunn says the project will undergo a three year evaluation with ISU performing the initial evaluation, and the site will continue to be monitored for many years.
Variety of foundations tested
During the first summer, subgrade materials were tested and utilized, giving the roads at the site a variety of different foundations. Three main categories included chemical stabilization, which included cement and fly ash; mechanical stabilization, which worked with mixing aggregate with subgrade materials; and reinforcement technologies.
While working with subgrade materials, equipment such as intelligent compacting equipment was utilized. The intelligent compaction equipment was able to take real-time data points from the ground beneath the roller and create maps that show how compact the ground is in specific areas. This can be used to create maps to identify problem areas early. Dunn notes that while the soil in Iowa is great for farming, it isn't necessarily great for roads. For this reason, learning more about subgrade stabilization methods, techniques and materials can help make Iowa roads better.
Last summer, paving was completed, which also brought testing of different methods and technologies. "Each asphalt road has a few different characteristics," Kruse says. Two main differences in asphalt are warm mix technology and standard hot mix technology. He says different kinds of rock and sand were also used in the project.
"The goal of this project is to keep progressing with improving materials and construction methods," says Dunn. By testing a variety of technologies in pavements and subgrades and monitoring their performance, the project could also reveal many more solutions to solving subgrade problems that we currently have limited options to fix, adds David White, associate professor at ISU.
Engineering feats aside, the pavement is sure to create a positive visit to the Central Iowa Expo site. "These roads should provide excellent areas for exhibitors to bring in their materials and nice walking paths for the many folks who come to the Farm Progress Show," Kruse says. "Boone County has a site that should excite exhibitors and show goers. No dust, no mud and valuable research that will go into making Iowa's roads last longer."
Partners in the project include the Iowa DOT, Boone County, Foth Infrastructure and Environmental, J.B. Holland Construction, Mannats, Central Iowa Expo, Center for Earthworks Engineering Research at ISU and Institute for Transportation Research at ISU.