Every year, a select number of road construction contractors, engineers, and owners turn concrete into gold. In late November, the American Concrete Pavement Association (ACPA) named the winners of its 18th annual “Excellence in Concrete Pavement Awards” program.
The awards recognize the contractors, engineers, and owners whose construction efforts yield high-quality concrete pavements in highway, street, and road applications for the year 2006. Specific criteria included quality, efficiency, smoothness, reduced costs, and minimal road-user construction delays.
After reviewing the applicants from the ACPA winners, Concrete Construction profiles two of the more unique projects from the decorated list of Gold Winners—the concrete pavement restoration of I-65 in Bullitt County, Ky., and the whitetopping project of Patterson Avenue in Kent County, Mich.
I-65, Bullitt County, Ky.
One challenge after another—this was the overall premise facing the I-65 concrete pavement restoration (CPR) project in Bullitt County, Ky., which included 52 lane miles being covered with 11-inch-thick concrete. General contractor Costello Industries Inc., Stockbridge, Ga., was responsible for nearly 400 full depth repairs, more than 2800 spall repairs, the cleaning and resealing of nearly 700,000 linear feet of joints, and the diamond grading of 650,000 square yards of concrete pavement.
After submitting a revised traffic control plan, its complex arrangement required grinding to begin on the first day of the project cycle with the resealing of joints beginning immediately afterward. Its proposal to start work on the inside lane first—as opposed to the original DOT plans that had the CPR work beginning on the middle and outside lanes—proved successful as it allowed Costello time to develop the necessary concrete mix designs in concert with Faulkner Construction, Louisville, Ky., as well as time to set up a concrete plant onsite.
Costello also faced numerous challenges, including being picketed by a local labor union because Costello employs nonunion workers. After agreeing to employ some of the union members, it proceeded with the project until the rain came. A series of weather problems during the construction cycle affected work, including a stretch of days that resulted in record rainfall and flash flood watches on four separate occasions.
Compounding the effects of the weather, areas of the construction project had to be undercut up to 5 feet in some cases, where soft and wet soils were encountered after concrete slabs were removed. “Areas of base and sub-base were soft and did not have a good compaction which caused faulting in the concrete. Costello, per the specs, replaced the moist soil with a dense aggregate and drains that would pull the moisture off to the shoulder,” says Rick Brockman, president of Costello, Sourtheast.
Eventually, Costello was able to concentrate solely on the CPR job. The major work on the project consisted of three primary CPR activities requiring 39 shifts of 10 hours per shift and six grinders, which generated thousands of gallons of slurry, all of which was diverted to three separate slurry pits. A total of 36 days were needed to seal joints behind the grinders (19,160 linear feet per shift).
As for the concrete mix, project specifications required that the Kentucky DOT be responsible for quality control/quality assurance (QC/QA) on the 24-hour mix design. “Because accelerator mixes are relatively new to the Kentucky DOT, by performing QC/QA, they feel they can ensure a quality project,” says Brockman.
Costello submitted six-hour and 24-hour concrete mixes to meet the minimum 3000-psi concrete strength requirement for opening the road to construction traffic and 3500-psi strength before opening the road to public traffic. The six-hour mix reached minimum strength in 4 1/3 hours and maximum strength in 5¼ hours. The 24-hour mix reached minimum strength in 12 1/3 hours and maximum strength in a little over 14 hours.
“It is a great honor that as a small company, we were able to be singled out as the best CPR project in the nation. This award belongs to the employees—and the wives who supported them—who worked hard on this project,” says Brockman.
Patterson Avenue, Kent County, Mich.
Completing a concrete overlay quickly and cheaply, while also saving local taxpayers money, may be a rare occurrence. Perhaps just as rare is the air testing of concrete pavement behind the paver, once it has been placed, to determine whether or not there is a large amount of air loss in the concrete once it passes through the paver.
However, this is precisely what occurred on the concrete overlay project for a 1-mile section of Patterson Avenue near Grand Rapids, Mich. Making the successful concrete overlay project even more unique was the fact that it was the first time a full mile of whitetopping was placed on a five-lane roadway in the state of Michigan.
According to the Kent County Road Commission (KCRC), less than $1 million was spent for the entire project and concrete pavement costs made up nearly two-thirds of the cost. The 4-inch white-topping overlay was priced at less than $13 per square yard to furnish and place.
Paving contractor WMRA Inc., Grandville, Mich., required only six days of mainline paving to place the five-lane section of Patterson Avenue. Additional days were required to fill in gaps and complete minor paving applications. Also of note, new turn lanes added to the existing road configuration.
“The widening was done at 36th Street, the intersecting street at the north end of the Patterson resurfacing. The widening included full depth, nonreinforced concrete as well as 4-inch concrete resurfacing over the existing hot mix asphalt pavement,” says Wayne Harrall, director of engineering for KCRC.
At the outset of the project, the existing 10¾ inches of asphalt was cold-milled to remove 4 inches of material and provide a good surface to which the whitetopping could easily bond.
After the concrete was batched at a nearby ready-mix plant, ready-mix truck drivers independently discharged the concrete immediately in front of the moving paver from their front-end discharge chutes, providing a constant flow of concrete to the paver. This minimized the time WMRA spent assisting with the placement of concrete.
As for the air testing of the concrete, WMRA and the county inspector worked together to coordinate and communicate the concrete air content results. The county inspector ran air tests on the concrete being discharged from the trucks in front of the paver. Additionally, at least one test per day was taken from behind the paver, a rather uncommon testing measure.
“It is not common to test the air after the concrete has been placed, it is typically done at discharge from the concrete mixer,” says Harrall. According to KCRC, there have been instances in the past of material interactions or other circumstances that cause the air content in the concrete to drop significantly from the front to the back of the paver.
The inspector removed a portion of the freshly paved concrete, remixed, and ran the pressure meter test. This was done to ensure that the in-place concrete would be durable. Typically, the difference in air content in the concrete from the front and back of the paver was near 1%, which is typical of most concrete whitetopping projects in Michigan.
“It seems to make sense that as the concrete goes through the paver and is consolidated, the water would tend to displace a portion of the air entrainment. Based on our field testing, we saw a 1% to 1.5% decrease between discharge sampling and final placement sampling,” says Harrall.
Considering the profound impact the test of air content behind the paver may have on the future of concrete roads in Michigan, the KCRC is proud to be recognized for the whitetopping project on Patterson Avenue.