Superpave Super Projects

Asphalt Article December 28, 2000
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I have one thing in common with my car. We both like smooth roads. The car likes it for purely mechanical reasons—potholes and ruts are just not good for its suspension. I like them because they are a pleasure on which to drive. Driving can be stressful enough without having to dodge potholes and avoid bumps. Roads smooth as a baby’s bottom are simply better pavements.

The folks at the National Asphalt Pavement Association (NAPA) also appreciate the importance of a well built road, and to encourage smooth asphalt highways, they offer a paving awards program. Margaret Cervarich, NAPA director of marketing, explains, “The purpose of the awards is to recognize the excellent pavements that are being built and to encourage others to do excellent work.” The awards are open to all hot-mix asphalt producers and contractors regardless of membership in the association.

“We use to give one award per year, the Sheldon G. Hayes, but we revamped the awards program a couple of years ago so we could have a broader base recognition,” said Cervarich. “Obviously, there is more than one good pavement being built every year, there are many.”

You might think that because NAPA is giving out a number of awards each year, it would be easy for a contractor to snag one of these, but that’s not the case. “We have developed quite a stringent process for evaluating the nominees,” said Cervarich. “They must submit the project’s specs and the records for how well they met the specs. They also have to submit density information. All of this is evaluated by NCAT [National Center for Asphalt Technology], which then comes up with a number score for each entry. The projects above a certain number win the Quality in Construction Award.”

Highway pavements above 50,000 tons that win a quality plaque may become eligible for the Sheldon G. Hayes award the following year.

E-470

One project being considered for a Quality in Construction Award is a project on E-470, a tollway near Denver. Stanley Opperman, project manager, Asphalt Paving Co., Golden, Colo., told ROADS & BRIDGES, “It’s a design-build project, which is publicly funded. It was funded through bonds, which will be paid off through toll collection.”

Matthew Alexander, manager of construction for the E-470 Public Highway Authority, describes the tollway, “E-470 is a tollway that is being constructed around the east side of the Denver metropolitan area. What is currently under construction is approximately 30 miles of a 48-mile loop. Of that, about half has been opened.

“All of the project’s main line will be paved in asphalt. The toll plazas will be paved in concrete as you enter and leave the plazas and all of the ramps are concrete.

“There will be a total of five plazas when the project is complete. One plaza was constructed before this project was started and this project builds three more. One more will be built in the final phase.”

“There are four segments in the project,” said Opperman. “Area One was the northern most and Area Two the southern most. They were completed and opened to traffic in June 1998.”

He continued, “Areas three and four are essentially complete from our point of view. But they are working on lighting and toll plazas, the things that come after the paving. The two center sections are required to open by June 30, 1999.”

Alexander concurred, “The project will be completed no later than June 1999.”

“Platt River Constructors is the design-build contractor and they also operated as the general contractor,” said Opperman. “Asphalt Paving Co. was a subcontractor to them. We constructed 29 miles of a four-lane highway and the associated crossroads that intersected with the highway. The project totaled about 986,000 tons of asphalt.”

Superpave design

The asphalt mix utilized the Superpave mix design procedure. “It’s a Superpave 3/4 fine mix with an optimum oil content of 4.9%” Opperman said. “We’ve used the SHRP [Strategic Highway Research Program] criteria for the design of the mix.”

The SHRP criteria was used to enhance the quality of the asphalt and its performance, which is subject to a three-year warranty.
All aggregates were produced by Asphalt Paving Co. at its Golden, Colo., quarry.

The 30-mile, four-lane highway, and associated crossroads, employs the design-build concept. When completed, just under one million tons of hot bituminous pavement (HBP) will be used. Areas one and two required 529,964 tons of HBP and were completed in early 1998. These areas were released to traffic in June 1998.

The asphalt was placed in a 20-month time frame within a three-year construction schedule. Much of the asphalt was placed on a section of cement-treated subgrade. Seventy-five percent of the asphalt was produced on-site using a portable plant. To help facilitate trucking efficiency, the portable plant was staged at three different sites. The remaining 255of the asphalt was produced at a fixed base plant in Golden. This was then wet hauled to the project.

In addition to expecting high quality, the tollway authority demanded value from the construction and long-term performance of the longitudinal joints. To achieve this, several joint construction techniques were used, as well as varying roller patterns, special end gates and a joint matcher. Special attention was also placed on crew training and awareness to ensure construction of quality joints. Finally a 20-ft rigid screed was used to completely eliminate the longitudinal joint at the centerline.

The asphalt paving on the project is essentially complete. “We are complete with the exception of 3,200 tons, but that is not on the main line,” said Opperman. “We have to finish a couple of city crossroads, which were not complete because of the cold temperatures. They will be finished in the spring. But you can drive the main line from end to end right now.”

Smooth paving on the Ohio Turnpike

A paving project performed by the Northern Ohio Paving Co., Twinsboro, Ohio, is another entrant in NAPA’s paving awards competition. Robert Bailey, vice president of Northern Ohio, describes the project. “The project consisted of widening six bridges, constructing two third lanes and building a new concrete barrier wall on a 5.95-mile section of the Ohio Turnpike.”

Access to the project was very difficult because all the work was performed behind a temporary concrete barrier with limited access points in a total working width of only 56 ft. Access also was limited by the 21-in. excavation and the fact that six bridges were being widened simultaneously with the roadway construction.

The limited access required fragmented paving between the structures and required 24-hour paving in order to meet the project completion date.

Despite these difficulties, Northern Ohio Paving was able to exceed the turnpike’s smoothness specification of 65 in. per mile averaging 44.23 in. per mile. They laid 167,232 tons of hot-mix asphalt, which met the turnpike’s requirements for gradation, air voids tines to asphalt ratio and F/T value.

They also met in-place density requirements established by the turnpike, which were 3.0 to 8.0 in-situ-voids.

The project also is a milestone for the Ohio Turnpike because the original turnpike mainline was constructed with portland cement concrete. As Bailey wrote in the project’s entry form, “The third lane additions are the commission’s first use of full-depth asphalt for this type of construction. The efforts of our company’s executive vice president Chuck Rauh, were instrumental in the turnpike’s decision to go full depth.”

Bailey feels that his company’s success at constructing a smooth riding pavement will mean that future third-lane construction will be done with full-depth asphalt.

Smooth move in Indiana

Another project up for consideration for NAPA’s construction award is the overlay of SR-15 near Goshen, Ind. Niblock Excavating Inc., Bristol, Ind., the asphalt paving contractor on the project, is committed to producing quality work through team work and a quality process outlined prior to starting the job. This philosophy was employed for the overlay of SR-15.

James Sonntag, project manager, Niblock Excavating, told ROADS & BRIDGES, “We did not start the work until the plan was approved by the state. We want all the team members to be involved.”

The project was approximately five miles in length, starting at U.S. 20 and heading south to the northern limits of Goshen, Ind.

“It involved some full-depth patching of some of the deteriorating joints, and then an overlay of 2-in. intermediate course with 19-mm material and 1 in. of surface course and that was a 9.5-mm mix,” said Sonntag. “We used around 101recycled mix in the intermediate course. No RAP [reclaimed asphalt pavement] was used in the surface course. It was a QC/QA Superpave project and the first project we had in which the state required a quality control plan.”

Teamwork and commitment were central to the project, according to Sonntag. “We always try to focus on doing quality work, and we have done this, but Indiana’s requirement really helped contractors and state people alike. It helped us to be on the same page and to build the project on paper before starting in the field. Yet the plan allowed for flexibility for changes that are needed to help the quality of the project.

“It helps open up a great line of communication. We have good communications in the field process as well as at the plant so it ties everything together. This was our first project where we were able to utilize this and it worked out well.”

Planning also was important. “We had to write up our process and make plans from the stock piling of aggregates all the way through the quality control process to implementing into the street,” Sonntag said. “Everyone is brought on board, because you review the plan with your project superintendent, your paving foreman and even your workers are made aware of what is going on. This all helps with the flow of the project.”

A state-approved quality plan also helped to open up communication between the contractors and the state. “In the old days, a line was drawn and you had the contractors on one side and the state on the other. Now a line is drawn and you have everybody on the same side,” said Sonntag.

With all the planning, the project resulted in a very smooth pavement. “The required smoothness tolerance for the profilograph on this project was 1.2 in. per tenth of a mile,” Sonntag said. “Our project averaged approximately two tenths of an inch per tenth of a mile. We had some areas on the project with a zero deviation. It was a very smooth project and I believe this was contributed to the open communication and the ability of our superintendent and foreman to work with the state officials on this job.”

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