When the Michigan Department of Environment, Great Lakes, and Energy (EGLE) helped fund a project on a stretch of County Road 607 in Dickinson County the intent was to test an unusual asphalt mix that uses pieces of old rubber tires to see if it could hold up in the harsh climate of the Upper Peninsula.
The project - a joint undertaking of the Dickinson County Road Commission, Michigan Technological University (MTU), and EGLE - was completed in June 2019.
Three 3,300-foot sections of road were paved for comparison and testing: conventional hot mix asphalt base top layer, engineered crumb rubber hot mix asphalt base with conventional top layer, and hot mix base with engineered crumb rubber as both the base and top layers.
The hope was that the rubberized asphalt would not only prove smoother, quieter and longer lasting than traditional asphalt but could also be made economically.
With two winters of experience in the history books, Lance Malburg, county highway engineer with the Dickinson County Road Commission, says that lab experiments performed at MTU show the performance of the materials has improved, with more resistance both to rutting during hot temperatures and cracking during cold weather. "Our hopes are that this project will demonstrate that rubberized asphalt not only is smoother, quieter, and longer lasting than traditional asphalt, but can also be made economically," he said.
The sections will be compared, monitored for 10 or more years, and tested by MTU and the Dickinson County Road Commission, specifically watching for cold weather cracking resistance of the two asphalt mixes.
The project utilized over 3,600 scrap tires and won a 2019 County Road Association of Michigan IMPRESS Award, which recognizes recognize county road agencies that demonstrate innovation with special projects in communications, operations and collaboration.
Photo caption: Workers at Dickinson County road project.