When workers resurfaced the southbound lanes of Interstate 57 last summer, they discovered that the stone matrix asphalt they put down on the road had unusual characteristics.

"We found the SMA didn't want to adhere to the polished concrete [existing road surface]," said Dirk Fuqua, engineer of project implementation for the Illinois Department of Transportation District One in Schaumburg. "It did eventually, but when it was hot, it was kind of moving around on us, and we didn't like that."

As a result, when it came time to resurface the northbound lanes this summer, the team working on the project added 0.75 in. of a 4.75-millimeter sand mix on top of the polished concrete, then topped it with 1.75 in. of SMA binder and another 1.75 in. of SMA surface.

The resulting new pavement is 4.25 in. thick, and its three layers all have different purposes, Fuqua said. The sand mix acts as a buffer between the polished concrete and the SMA. The binder is regular stone aggregate, while the surface is a steel slag aggregate.

"We put the steel down for friction characteristics; it provides better protection against skidding and accidents," Fuqua added. "SMA itself is a mix. It's rock on rock. It's got larger stone in there. In a normal bituminous mix, the stone and sand are bound together with the asphalt.

"In an SMA, the rock is fairly large, and the rock rests on top of the rocks. So it's a really solid layer for us. We're using that in all our expressway resurfacing."

12 Mi. of Resurfacing

The project involves patching and resurfacing a 12-mi. length of I-57 from Halsted Street south of the Bishop Ford Expressway down to Interstate 80, as well as rebuilding bridge decks between 119th and 159th streets. This summer's work is budgeted at $43 million.

The total project is worth $80 million and is slated for completion by Oct. 31. Lemont, Ill.-based K-Five Construction Corp. is the general contractor.

This is the first resurfacing for I-57, a roadway whose original construction dates back more than a quarter century. Prior to the work, I-57 was in "decent shape," but a number of cracks had begun appearing and the road was in the early stages of erosion, Fuqua said.

"We needed to go in and patch and surface before the road turned to gravel on us," he added.

Robert DeFrancesco, superintendent with Lemont, Ill.-based K-Five, said patching consisted of removing existing pavement and laying down new concrete.

"The holes weren't deep," DeFrancesco said. "It was just deteriorated concrete. It was bad concrete that had to be removed and replaced. There was a lot of patching."

Special attention is given to stretches of roadway leading up to bridges because they contain a lug system that helps prevent some traffic pressure from impacting the bridges. To replace the lug system, contractors first remove the "continuously reinforced concrete" near the bridges, DeFrancesco said.

After removing that pavement, the area is excavated, then 12 in. of aggregate stone are placed in the bed, topped by 4 in. of asphalt base. Forms are then set, reinforced steel laid down and 13 in. of concrete poured to create the roadway.

Safety of Workers

As it does on all road projects, IDOT is working to ensure safety for workers. Because stage construction is used, traffic is being reduced from three to two lanes through the work zone. All workers are behind a barrier wall or barricades, Fuqua said.

DeFrancesco said that "safety is a big thing with the state of Illinois." He said extra signage and a multitude of flaggers are helping ensure safety for both the workers and the motoring public.

"When we first started, we had weekly meetings, and now it's pushed back to every two weeks," he added. "At those meetings, we hit on safety, traffic control, everything.
And that involved the state of Illinois, the general contractor and all [eight] subcontractors."

Fuqua said there has only been one serious blemish to a good safety record. "A motorist got behind the barrier somehow and hit one of the workers who was doing pavement striping," he added. "He was not a state employee, but with one of the contractors."

DeFrancesco said the worker was killed. "We'd completely closed off lanes where the [motorist] had no business at all," he said. "The guy just came into the closure and hit him."

Bridge-Deck Work

Fuqua said workers are on the project from approximately sunrise to sundown, but if the schedule demands it, longer hours may have to be put in later this summer.

Had the project involved only resurfacing, the work probably could have been finished at night, "but we have those bridge decks, so we can't have just nighttime closures and still be able to pour and cure concrete," he added.

Filled with potholes and in "bad shape," the decks had become a chore for IDOT to maintain, Fuqua said. As a result, the decks are being removed from the overpasses.
Steel and bearings that need repair are being fixed, and contractors are then forming up and pouring concrete atop the steel.

In removing the bridge decks, the existing concrete was broken and the pieces removed. That broken concrete will be reused in future jobs.

Fuqua acknowledged that completely rebuilding the bridge decks is hard work but added that IDOT assigned experts to the job.

"Actually doing it on I-57 under these conditions is easier than closing like half a bridge deck and repouring it," he said. "That way would take twice as long; we'd be out there four years instead of two years."

IDOT issued press releases, published and distributed brochures and met with community leaders to help get the word out to the public that traffic would be reduced to two lanes and running slower than normal. "Eventually people learned they needed to slow down in the work zone and they could make it through without any difficulty," Fuqua said.

Noting the problems with the SMA on polished concrete last summer, Fuqua said things are better this year. "It seems like the job is going smoother this year, and I'm quite pleased with it," he added. "We're doing $80 million of work in just two years, without too much congestion."