Reconstruction of I-96
Putting Pavement to the Test

The project was designed so crews would first work on the local lanes while leaving the express lanes open.

By Peter Fretty

Highways, which are often viewed as “functioning” equipment, require a certain amount of maintenance, just as the vehicles traveling them need service. In some cases, this upkeep involves replacing worn-out parts.

For the I-96 corridor, which runs from the Southfield Expressway to Roosevelt Road, the road’s tired condition was a primary motivator to act, explains Victor Judnic, Engineer with the Michigan Department of Transportation (MDOT). There was, however, an exciting aspect to the $85-million reconstruction of this stretch of highway: It presented a fantastic opportunity to compare the performance capabilities of concrete and asphalt. According to Judnic, the project design incorporates hot-mix asphalt in one direction and high-performance concrete in the other.

“This seems a little odd, but the industry has wanted to go to a perpetual pavement system, which involves a deeper section of asphalt rather than relying on concrete,” Judnic says. “Many feel this approach could have long-term advantages for the freeway construction process. Usually, freeways are concrete, but if this works out, it will effectively demonstrate how a hot-mix asphalt combination that requires minimal rehab work every 20 years or so could benefit the state and the public over the long term.”

Race Against the Clock

While many construction projects have time limits, the I-96 work is especially tight, in large part because of the Major League Baseball All-Star Game in July 2005, which took place near the project’s halfway point, and the 2006 Super Bowl.

The project design incorporates hot-mix asphalt in one direction and high-performance concrete in the other.

These time constraints make the job somewhat challenging says Robert Farina, Project Estimator at Ajax Paving Industries, Inc. “Considering that during this time we will use approximately 250,000 tons of asphalt and 213,800 square yards of concrete pavement, there is a vast amount of scheduling and coordinating that needs to take place to accomplish the goal and meet the schedule,” he says.

Fortunately, another highway, I-94, serves as the primary truck route, so crews do not have to deal with heavy freight volume on the roadway. However, I-96 is the primary commuter traffic route in and out of Detroit, so mornings and evenings are often chaotic, especially when traffic lanes are kept open through the construction.

To facilitate the process, the project was designed so crews would first work on the local lanes while leaving the express lanes open. Once the local lanes are complete, the construction team will then open those lanes and complete all work on the corresponding express lanes.

“We always have a detour if we have to close any portions during the weekends,” Judnic says. “Our goal is to have as little impact on traffic as possible, especially considering the road accommodates roughly 85,000 vehicles each day. While this approach helps keep traffic moving, the road capacity is still lessened, which causes congestion.”

On the Asphalt Side

As a subcontractor of Dan’s Excavating, Inc., on the I-96 project, Ajax started work in February 2005 on total reconstruction of the first section, which runs from Southfield Road to Davison Road.

This work involves removing the existing pavement and then placing 14 inches of asphalt on the westbound section and 11.5 inches of concrete on the eastbound section. The second phase, which runs from Davison Road to Roosevelt Road, calls for milling the existing asphalt and placing 3.5 inches of hot-mix asphalt. In addition, Ajax is conditioning and performing patchwork on the existing concrete.

According to Judnic, some innovative tactics are being employed on this project. First, the asphalt itself is 14 inches thick placed in five courses. Another unique quality is the top layer course has a gap-graded design. In most instances, the top asphalt course is a fine mix that keeps water from penetrating other sections. The mix in use on this project uses a large-stoned top course instead.

“To make this work, we use a cellulose material, which, when combined with the asphalt binder, fills the gaps the bigger stones create,” says Judnic. “This still creates a sealed-off effect like a normal mixture, but it has more of a stone content, so it can hold up better with less cracking, movement, and a reduction in noise. While MDOT has used this mix in the past, this is the first large-scale project in the Detroit area. If all goes as planned, this approach will be the trend for the future.”

On the Concrete Side

The new concrete for I-96 makes up a far smaller portion of the project budget, totaling around $7 million. Ajax’s Concrete Project Manager Yvonne Kur notes that, in the 2.5 miles of reconstruction, the concrete division is replacing the current roadway with 11.5 inches of nonreinforced, high-performance concrete. Ajax used this high-performance mixture on a few projects last year in the metro Detroit and Grand Rapids areas, Kur says.

“Last year, Ajax and MDOT went through a learning process on this innovative mix design. With the successful partnering of MDOT’s local TSCs, Ajax was allowed to make small modifications to specifications,” she says. “These modifications enhanced the necessity for an intense quality-control process by the contractor. This process would ensure that each day of production would produce a consistent mix.”

High-performance concrete is a dense graded-mix design that involves two aggregates (a coarse or modified 6AAA and an intermediate or modified 26A) and sand (2NS). “Using this approach gives us the ability to monitor and adjust the mix to consistently maintain uniform gradation of all the aggregate sizes,” says Kur. “This uniformity allows for less cement paste while not compromising the results of the 28-day strengths. To date, all the 28-day strengths have exceeded the minimum strength of 3500 psi.”

The innovative materials and methods used in the I-96 reconstruction match the project’s overall inventiveness, a design that will improve the roadway while giving MDOT an important test site for evaluating the longevity and durability of the materials used. The information gathered over the life of this stretch of road may go a long way toward reducing the frequency of highway maintenance, which could cut costs dramatically and remove a major source of irritation for motorists everywhere.

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