The spring season is a busy season for the Delaware Department of Transportation.
While many large, high-profile projects get attention, crews are also working throughout Sussex County repaving sections of smaller roads.
Matt Schlitter, South District assistant maintenance manager for DelDOT, said how, why and when the state chooses to resurface a road is often a topic of conversation.
DelDOT uses a simple formula when choosing to resurface a road. If a roadway has fewer than 500 trips per day, it’s likely to receive tar-and-chip treatment. It all comes down to money.
It costs $17,000 per mile every seven years to maintain a tar-and-chip road, while it costs about $225,000 per mile to convert to asphalt pavement. Asphalt lasts about 15 years and costs about $300,000 per mile to remove and replace, Schlitter said.
The state has about 600 miles of tar-and-chip roads, and converting all roads to asphalt would cost about $135 million. In comparison, he said, it costs about $10 million to maintain existing tar-and-chip roads.
Schlitter said he often receives complaints about tar-and-chip roads, usually right after they’re sealed.
“Chip sealing is not as easy as putting glitter on glue,” he said. “It’s not an exact science. It takes a very experienced crew. Workmanship can make or break a chip seal job.”
After receiving complaints about loose stones on tar-and-chip roads, DelDOT changed its approach and introduced a sweeping program four years ago in Sussex County.
“We drastically reduced the amount of stone applied on the roadway,” Schlitter said. “Too much stone can cause premature failures to the chipped surface.”
The makeup of the tar-and-chip asphalt in previous years meant the road could not be swept for three days without a high risk of damage to the surface. A change to the chemistry allows DelDOT to sweep the same day, Schlitter said.
The state is also beginning a new program that could drastically reduce the cost of tar-and-chip roads. Three years ago, Schlitter said, DelDOT experimented using recycled asphalt as stone on tar-and-chip roads, and there have been no issues to date.
“Stone is very expensive for DelDOT, as we have no local stone quarries,” he said. “We import some from Pennsylvania. Unfortunately, we pay the same for shipping as we do for the stone itself.”
If DelDOT moves forward with an expanded recycling program, Schlitter said, it could drop the cost of a tar-and-chip road from $17,000 per mile to $5,000 per mile, for a savings of about $2 million per year.
DelDOT is also trying to save money through its pavement preservation program to extend the life of roads. Last year, DelDOT started fog sealing asphalt pavement. The treatment, typically used for roads 3 to 5 years old, seals smaller cracks and voids in the wearing surface. It’s different from crack sealing, which seals larger cracks to prevent water from getting below the surface.
DelDOT is also looking at other cost-effective approaches to extend the life of roads.
“DelDOT has many great innovations on the horizon which will continue to offer a cost savings to the taxpayers while improving our roadways,” Schlitter said. “As construction begins, we understand it can cause an inconvenience to the traveling public. We ask you to practice patience to protect our men and women working on the roadways.”