ASPHALT ROAD CONSTRUCTION: Three-horse race

March 10, 2011

Rebuilding high-volume interstate highways without creating or worsening gridlock is one of the great road-management challenges of modern times, and it has given rise to new priorities for highway agencies.

 

Rebuilding high-volume interstate highways without creating or worsening gridlock is one of the great road-management challenges of modern times, and it has given rise to new priorities for highway agencies.

Today, to rebuild some critical metro corridors, agencies put as much premium on traffic control and rapid project completion as they do low cost. In 2009, there was no more dramatic example of this than Kentucky’s Revive 65 project, which saw 30 lane-miles of I-65 in Louisville demolished and rebuilt from the subgrade up in less than 90 days from the time the contract was let.

Difficult to work with

Located just south of downtown Louisville and bordering the Louisville airport, the problem section of I-65 stretched 3.5 miles south from the I-264 interchange to Fern Valley Road. Originally built in the 1950s, the road had been widened in the 1980s but had never been rebuilt. The old concrete pavement was far past its design life and plagued with serious transverse cracking and longitudinal joint failures. Of greatest concern to the Kentucky Transportation Cabinet (KYTC) was severe problems with differential settlements of the concrete slabs, which created surface irregularities that posed a danger to motorcycles and other small vehicles.

More than 164,000 vehicles traveled this section of I-65 on an average day.

“It was a very difficult section of road to maintain,” said Matt Bullock, a KYTC district engineer who had oversight of the project. “We had differential settlements of the concrete slabs creating dangerous driving conditions. Because of the high traffic volume, we’d do overnight repairs—take out a slab and put in a fast asphalt fix so the lane could be opened to traffic quickly.”

But, Bullock said, there were places in the old road where the agency could not keep up with differential problems. A rebuild was needed, but like many other agencies, the KYTC just didn’t have the funds.

“When the federal stimulus package came along,” said Bullock, “this project was ready to go.”

The agency secured $18 million for the project from the American Recovery and Reinvestment Act and added funds from the state’s interstate maintenance budget to pay for the rebuild. The project was put out to bid in August 2009.

High volume at high speed

The KYTC’s plan for the rebuild called for the new pavement to be a full-depth asphalt structure.

“We specified asphalt for this project because it could be built faster and because it would be easier to maintain in this high-volume section of roadway,” said Bullock.

The state has many years and many miles of experience with full-depth asphalt pavements in both rural and high-traffic areas, including a number of roads that won Perpetual Pavement Awards from the Asphalt Pavement Alliance and Quality in Construction Awards from the National Asphalt Pavement Association.

Because of the suspected subgrade problems, the project required complete removal of the old concrete and undercuts as needed to stabilize the subgrade.

“That part of the road is built on boggy land with a high water table,” explained Bullock. “There are height restrictions that prevent us from just adding more fill and building a higher structure.”

In addition to the demolition and rebuild work, the massive Revive 65 project called for the repair or elimination of bridge joints and upgraded guardrail end treatments.

The project was awarded to a three-contractor partnership on Aug. 27, 2009. The tri-venture partners—Louisville Paving Co.; Hinkle Contracting Co., a Summit Materials Co.; and Hall Contracting of Kentucky Inc.—began work on-site on Sept. 18.

Their task was daunting. In this section of I-65, the road varied from three to five lanes in each direction—a total of 30 lane-miles that needed to be rebuilt in less time than resurfacing would normally take. In less than 60 days, they would demolish and remove 204,000 sq yd of old pavement, place 35,000 linear ft of barrier wall, excavate 92,000 cu yd of sub-base and place 360,000 sq yd of geotextile fabric, 73,000 tons of No. 2 aggregate, 58,000 tons of dense-graded aggregate, 157,000 tons of base and intermediate asphalt and 15,878 tons of surface-course asphalt.

Working 24 hours a day, seven days a week, the contractor partnership completed all work on the driving lanes on Nov. 15, on schedule.

Fixing the surprise

Bringing in a project of this magnitude on time requires a rock-solid plan and great teamwork between the contractors and the state highway engineers.

“When we looked at the project,” said John Dougherty, vice president of Louisville Paving, “we thought we might be able to do it ourselves, but only if everything went just right. And of course, things never go just right. We needed more firepower.”

So Louisville Paving approached Hinkle Contracting and Hall Contracting about a joint venture. Hall Contracting handled the bridge work, while Hinkle Contracting and Louisville Paving handled the road work. Louisville Paving functioned as the lead contractor with project oversight.

The three partners fit together easily, as did the many subcontractors employed on the job. Subcontractors handled the initial breaking of the old concrete and excavation of the roadbed, said Dougherty, while Hinkle and Louisville put in the base and asphalt lifts.

Communication and coordination between contractors was essential: “We had six different crews working on the site at times,” said Dougherty.

The contractors started with the northbound lanes, keeping at least two lanes of traffic open at all times. One of the project’s first major challenges came when the northbound lanes were excavated to the sub-base, which was much weaker than anyone had anticipated.

“We had anticipated poor soils and water problems,” said Dougherty, “and the project specifications allowed for undercutting weak areas. But when we got down to the subgrade we found that most of it needed to be undercut or stabilized.”

That discovery marked one of several times the contract had to be changed to deal with changing realities. An unusually wet autumn also forced an extension of the completion date.

One of the keys to the project’s success was how closely the KYTC engineers worked with the contracting team.

“There are always surprises on a job,” said Dougherty. “You need someone in place who can make decisions quickly, in hours not days, and we were very fortunate in that regard.”

Three KYTC engineers worked closely with the project principals: Jeremiah Littleton, a liaison from the KYTC central office; Matt Bullock from the District 5 office; and Larry Collins, a.k.a. “Red Dog,” who was the resident engineer.

The effectiveness of the agency-contractor relationship not only enhanced the quality and timeliness of the job, it also led to some creative problem solving in dealing with the weak subgrade. On the northbound lanes, the team used undercuts and geotextiles to stabilize the subgrade, but on the southbound lanes they used soil stabilization with portland cement and lime additives to achieve the same stability. The time involved was about the same, but the soil stabilization solution saved some material and cost. In all, dealing with the unanticipated subgrade problems added $2.3 million to the contract and six days in each direction.

Once the subgrade was prepared, it was topped with 12 in. of No. 2 crushed stone and 4 in. of dense-graded aggregate. An asphalt base using PG 64-22 binder and 1.5-in. aggregate was placed in three lifts of 4.5 in. each. The base was covered with a 3-in. intermediate layer using a PG 76-22 binder and 1-in. aggregate. For the surface course, KYTC specified a 1.25-in. lift of Superpave with a PG 76-22 binder and 0.38-in. aggregate.

Material transfer vehicles were used on all lifts, a standard requirement on Kentucky interstates.

Website traffic

Contractors and agency personnel alike had anticipated that traffic control would be one of the most difficult parts of the project, but thanks to good planning, an outstanding public-awareness effort and the speed of the work, the traveling public experienced only minor inconveniences from the rebuild. The contract specified that at least two lanes of traffic had to be open at all times, and at least three lanes during peak traffic hours.

Local motorists also benefited from an exemplary communications effort by the commonwealth of Kentucky. The KYTC created a project website that kept motorists updated on progress and traffic logistics. It used radio and television advertising as well as press releases to alert motorists of impending lane closures. And, employing one of the newest communication technologies, the agency’s public-information group received pre-rush-hour updates from the contractors for twice-daily Twitter feeds to subscribing motorists.

This effort was supplemented with variable message signs on I-65 and other interstates in the area. Leaflets were distributed to air travelers at the Louisville airport. And KYTC kept trucking organizations and motorist associations informed about the project and lane closures. The public-awareness effort even included direct presentations to some of the major employers and distribution centers in the area.

And the KYTC got political support for the awareness effort when Gov. Steve Beshear and Louisville Mayor Jerry Abramson kicked off the campaign with a press conference at the UPS Global Operations Center, overlooking the project area.

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