Research from Michigan Technological University may help make Michigan’s roads more durable.
When Zhanping You began working at Michigan Technological University, he hoped to further develop an idea for how to use old tires. In the 2000s, some road projects tried to use small granulated tires in road mixtures. The practice was scrapped like the tires. But You knew it was the start of something larger.
Tires without a tread have very few uses. Often those tires end their journey at landfills or, worse yet, in fields or rivers. You, a research professor at Michigan Technological University, says while the treads may have worn down, old tires could be recycled and used to make roadways more durable. A major hurdle in the 2000’s to using rubber asphalt mixtures in road projects was the technology available for testing and development available to researchers.
“And like today, we have a lot of really advanced equipment, a lot of advanced design methodologies. So we can really make the asphalt for the mix design at a high level. So for example, we measure a lot of things like crack resistance, which is not easy to achieve in the past,” said You, director of the Michigan Tech Transportation Institute.
You has worked with research teams to develop two methods: chipseal maintenance and rubber asphalt mixture. Each method has already been used in MDOT projects. Last summer, a stretch of road in Saginaw used chipseal, and another project in Dickinson County used the asphalt mixture.
“So we see there are quite a few benefits. One is to improve the road resistance. That really means the roads are not going to easily get deformed under heavy load, heavy trucks. So the road resistance is really getting improved significantly,” You said.
You says in road engineering, one of the biggest challenges is water. Moisture developing under pavement creates potholes and can create weak points that cause buckles. By adding rubber to the road design, the pavement can have more give between temperature fluctuations.
“They can have really good adhesion to the aggregates, which are the stones. So that really makes the materials pretty hard. It’s really not easy to get the damage underneath from water,” You said. “A lot of times the pavement failure really starts from the wet places.”
Michigan’s climate makes road engineering and design difficult. You hopes to continue work with additional partners to further test the chipseal maintenance and rubber asphalt mixture.
“A lot of roads in Michigan really start with the cracks. People really think that’s not easy to get rid of it. There are ways. So when we are using tire rubber into the mix design, we see the crack resistance improve dramatically. That tells us even under crazily low temperature situations like here in the UP, the roads are not likely going to crack because these materials are so high in fracture resistance,” You said.
Currently, You’s team at the Michigan Tech Transportation Institute works with 20 of 83 Michigan counties, the Minnesota Department of Transportation and the Federal Highway Administration. He expects to work with the city of Ann Arbor this summer on a road project that will use the chip seal method. Next summer, the research could help improve roadways in the City of Detroit. Learn more about how recycled tires can make roads more resilient can find more information here.
