Six different types of material were used on the I-55 project including 4,800 tons of the N105 binder, a polylevel binder used on miscellaneous enter and exit ramps, 30,000 tons of N70 surface was applied on top of the polylevel binder and the shoulders, 19,000 of N70 binder was used on the left shoulder under the N70 Surface.
During the I-55 project, crews would remove 2 inches of the existing surface and open it up to traffic. Once work was far enough along, crews would drop back and the paving train would grind the final 2 inches off, sweep, prim and pave 2 inches of Stone Matrix Asphalt.
The I-55 project required the left shoulders to be rehabilitated to accept rush hour paced bus traffic. As a result, N70 Binder and N70 surface were installed only for the left shoulders.
Plote Construction crews used two Wirtgen 2200 grinders to remove 2 inches of the existing surface during the resurfacing of Interstate 55 in Illinois.
Communication and efficiency are two skills every contractor must actively use to achieve success. The resurfacing and bridge rehabilitation of Interstate 55 in Chicago required just that of contractor Plote Construction, located in Hoffman Estates, IL. Plote encountered a three-mile lane closure restriction and a tight night schedule that created a few challenges. Despite these challenges, crews successfully completed the full-depth patching and resurfacing of 60 lane miles stretching from County Line Road east to Kedzie Avenue.
The project began May 1, 2011 and was completed Oct. 24, 2011 with work taking place between the hours of 8 p.m. and 5 a.m. Repair work became necessary due to several areas of damage to the surface.
“The pavement had been patched quite a bit, and some of the surface had joint repairs between the lanes that were failing,” says Rick Zera, general superintendent at Plote Construction. “Whether there is a future plan of reconstructing the road, it was time to take it down 4 inches and then replace the 4 inches to give it some life.”
Preparing the project
With three lanes in each direction and several areas with a fourth auxiliary lane leading to and from exits, Plote crews first performed a full-depth Class D HMA patching.
“We went through the areas designated by the engineers removing the existing wearing surface and base to get down to the stone that was below it, and then we filled the void with N105 binder patching,” Zera says. “We did that on a nightly basis, and it took us the first month of the project.” The N105 binder is a larger aggregate product; therefore, a stronger mix that is often used in heavy traffic situations.
Six different types of material were used on the I-55 project. These included: 4,800 tons of the N105 binder; a polylevel binder used on miscellaneous enter and exit ramps; 30,000 tons of N70 surface applied on top of the polylevel binder and the shoulders; and 19,000 of N70 binder used on the left shoulder under the N70 Surface.
The right and left shoulders used different material due to road adjustments. “The left shoulders on this project and another adjoining IDOT (Illinois Department of Transportation) project west of I-55 required that the left shoulders be rehabilitated to accept rush hour paced bus traffic,” Zera says. “The left shoulders were ground and we installed the N70 binder and N70 surface. On the right shoulders of I-55 we only installed the N70 surface and forgo the binder as a cost-saving move on IDOT.”
From 2” down to 4”
A typical night on the main line consisted of two operations, one in each direction, using two Wirtgen 2200 grinders to remove two inches of the existing surface. “Then, the road was striped and traffic was opened up on the ground two inches,” Zera says. “Once we hit a point where we would be far enough along, we would drop back and the paving train would grind the final two inches off, sweep, prime and pave two inches of Stone Matrix Asphalt (SMA) binder on a nightly basis. Per crew we would get about 1,200 tons of binder installed.”
Plote crews would only grind out what they were able to replace, and they were able to remove the top two inches because the remaining material on top of the base was still in good condition. A total of 60,000 tons of SMA binder and 66,000 tons of SMA surface were used in the project.
Plote used a Caterpillar AP1055 rubber-track paver and a Barber-Greene BG260C rubber-tire paver to complete the mainline paving, and a Caterpillar AP600 rubber-tire paver to complete the paving of the shoulders. Other essential equipment included two Roadtec SB2500 material transfer vehicles (MTVs) and two three-wheel ballasted rollers, two Sakai RH2s and four Ingram Compaction AS315s.
This project also achieved a high rideability score. When paving the surface, Plote used three three-wheeled rollers with an additional fourth roller as the finishing roller.
“We bump tested as we went looking for obvious defects to take out with the fourth roller when the mix was still hot,” Zera says. “We feel that really enhanced our profilograph results.”
Plote also used inlaid tape for the skip-dashes between lanes. “The fourth roller also allowed for the installation of the tape, and it didn’t slow down the paving installation because we didn’t need a third roller to drop back and work with the tape installation,” Zera says.
Pay for Performance (PFP)
Unlike most projects Plote has completed, the pay factor for project I-55 came from a new system of judging pavement — Pay for Performance (PFP). This pay factor system, used by IDOT, examines the pavement in three different categories resulting in a certain percentage of the pay scale for each category. The categories include voids at 30 percent pay factor, voids in mineral aggregates (VMA) at 30 percent pay factor, and density at 40 percent pay factor.
“Your asphalt is judged in 10,000-ton lots, and each lot of the PFP is 10 1,000-ton sub-lots,” Zera says. “Your 1,000-ton sub-lots are judged on random cores from field checking for density from one random sample from the HMA plant. The random samples are taken after the mix is dumped into the truck, and IDOT will pull over the truck and take a sample from it. This will determine the voids and VMAs of the 1,000 ton sub-lot sample.”
The field samples, testing the density, are taken every 1,056 feet in a random location of the lane paved.
For I-55, Plote used 126,000 tons of combined SMA binder and SMA surface totaling in 12 lots of PFP. As a result, this was one of the largest PFP project to be completed in District 1.
Contractors have a base line they must meet, with a little leeway above and below the base line. This also affects the pay factor.
“When you go over the limit of tolerance or under the limit of tolerance, that affects your pay factor for the 1,000-ton sub-lot,” Zera says. “You can be penalized for your inconsistencies. If they are extreme enough you can be forced to remove and replace the 1,000-ton sub-lot at no cost to the owner.”
Along with a different system for determining the pay factor, Plote also encountered a few challenges maneuvering equipment and crews with a limited 3-mile length of closure in one direction.
“We would extend our three-mile lane closure with several of our operations from our initial grind to the installation of lane markers and reflectors,” Zera says. “We would start at the east end working our way west. When were far enough down the line we would have to extend the lane closure an additional mile, but we would have to go back to the beginning to pick up the closure from the first mile so there was never more than a three-mile closure.”
It was challenging choreographing the different subs that worked within the closures to make sure they didn’t exceed the lane closure limits. Zera credits the success of completing this difficult job and maintaining a safe and efficient work zone to the communication between the day and night superintendents.