By Sue Moore
An experimental rubber-asphalt surface, applied in recent weeks to a portion of W Avenue about 4,000 feet long east of Schoolcraft, will be evaluated for durability and noise in coming months by the Michigan Technological University team which developed the mix.
It may not be noticed by motorists.
W Avenue is a main connecting link between the Villages of Schoolcraft and Vicksburg. It’s designated an all-season road, capable of standing up under heavy trucks when other roads are placed under late-winter weight restrictions.
In the same project, the rest of the road eastward toward Portage Road and Vicksburg was variously resurfaced with a conventional hot mix asphalt (HMA) overlay, conventional chip seal, and hot rubber chip seal. The conventional sections will serve as control test sections.
Tests for endurance and noise will be carried out for the next year by a team from Michigan Tech in Houghton. Headed by Dr. Zhanping You, the team developed a specialized rubberized material never used before in a paving mix.
If successful, it could lower costs for the use of scrap tires in road building and prolong the service life of roads, according to Dr. You. The Road Commission of Kalamazoo County was chosen by his team for implementation because a member of his staff is a friend of Managing Director Joanna I. Johnson and knew she would be amenable to the idea and good to work with.
Her staff was instrumental in the successful experiment, taking great pains to study the technology and making it work on the two-mile stretch of road. The chosen portion of the road is heavily traveled –approximately 3,600 vehicles per day It was scheduled for resurfacing in 2018 and has a parallel road in VW Avenue that could be useful for comparison.
The MTU team returned to W Avenue in September to measure the noise levels on the newly resurfaced road. They found noise over the hot-rubber thin overlay section to be two decibels lower than the rest of the road.
The operation required specialized processing involving lots of chemistry to provide just the right mix of scrap tires and other materials that typically go into making conventional hot mix asphalt. This mix was developed by a colleague of Dr. You’s in Portugal. The hope is to be able to manufacture the specialized mix in Michigan and the United States if successful.
The Michigan Department of Environmental Quality (DEQ) awarded this Scrap Tire Development Grant in cooperation with MTU to the Road Commission. The grant amount was $221,964 with a total project cost of $443,928. The Road Commission share was estimated at $136,964. The original project application was estimated at 13,672 scrap tires to be recycled. Based on the estimated final quantities 7,500 scrap tires were recycled. This was primarily based on the adjustment in the hot mix asphalt overlay; “We reduced the thickness and therefore we had less tires,” Johnson said. MTU’s match was $85,000.
“The grant does not cover the full costs of a project and we are still finalizing this project’s costs. Due to the unforeseen complications with the equipment with the chip seal trial, we anticipate being over budget,” Johnson said.
“Scrap tire innovation is nothing new to the state. However, the type of recycled tire material used for this project has not been used here before,” Johnson said.