There comes a time when you just have to give up on a road. That was the case for the concrete freeway where I-64 and I-75 split north of Lexington, Ky. Numerous patches and diamond grinds had been unsuccessful. Meanwhile the continuing delays were creating congestion on this busy interstate highway. The crumbling road also gave motorists a rough ride, adding to their frustration.
In addition, Lexington will be the host of the World Equestrian Games in 2010. Clearly something had to be done to smooth the way for commuters and prepare for the onslaught of visitors to the state for the upcoming competition. The Kentucky Transportation Cabinet turned to ATS Construction of Lexington to carry out the project of replacing the concrete structure with a smooth, durable asphalt highway.
Work began in earnest on the westbound lanes with the removal of the old concrete road and the rebuilding of three traffic lanes plus inside and outside shoulders. ATS contracted with Central Rock of Lexington to break up and remove the old concrete roadway. Working around the clock, the crews of Central Rock fractured the concrete and scooped it up into waiting trucks to be hauled away. In six days the crew was able to break up and haul away some 64,000 sq. yd. (53,512 sq m) of failed concrete road. (They were able to accomplish these results on the westbound lanes in 2006 and on the eastbound lanes in 2007.)
Once the old concrete road was removed, the soft subgrade presented a problem. ATS addressed this circumstance with 12 in. (30.5 cm) of #2 stone, topped with a 4 in. (10.2 cm) dense-graded asphalt base. On top of this base, crews used large stone (#57 AASHTO) to build a 4-in. asphalt treated base “drainage blanket.” This porous layer channels water away from the road into edge drains, providing a solid foundation for the highway.
Building on this foundation, the ATS crew laid two 5.5-in. (14 cm) lifts with 1.5-in. (3.8 cm) maximum aggregate, followed with two more lifts of 3 in. (7.6 cm) each asphalt base with 1-in. (2.5 cm) maximum aggregate. The paving crew then topped the road with a 1.5-in. (3.8 cm) surface course of polymerized asphalt. All the asphalt was Superpave, except the drainage blanket.
Eliminating Congestion
With congestion continuing to be a problem, time was of the essence. ATS and its crews were able to complete the westbound lanes in 66 days, qualifying for incentive pay. The lanes were completed by October of 2006, allowing traffic once again a free flowing ride.
This project called for more than just a simple rehabilitation. “To fix this road’s failures meant a full-depth replacement,” said Andy Barber, the Kentucky Transportation Cabinet resident engineer of Fayette County. “Not only did the contractor need to address the drainage issue, but he also had to be concerned about smoothness. The motorists were getting a very rough ride. For the new pavement, we asked for a 1.17 to 1.07 profilograph reading and the contractor delivered.”
With motorists now gliding smoothly along the westbound lanes, ATS took on the eastbound lanes beginning July 8, 2007. The deadline was to finish fixing the failed concrete roadway by the conclusion of the paving season. With all lanes complete, ATS used 180,000 tons (163,293 t) of asphalt to rebuild the 1.5 mi. (2.4 km) of freeway. The project included four major interchanges.
“This is a very busy roadway and has been a bottleneck causing traffic to stack up,” said Brian Billings, vice president of engineering of ATS. “In order to get everything done as quickly as possible we were using two of everything — two crews, two pavers, two material transfer vehicles and double the amount of rollers as would be required for a normal job.”
Thanks to the careful planning and hard work by its crews, ATS was able to wrap up the paving of the eastbound lanes in 51 days. The project was aided by having a smooth flow of asphalt production from the company’s new plant located near Lexington, which provided up to 80 percent of the asphalt required for the job.
“We have two asphalt plants in Lexington which provided the mixes needed for our other customers,” said Billings. “That enabled us to stay focused on this I-64/I-75 job and get it done quickly, maintain high quality and provide a durable, smooth road.”
This article was reprinted with the permission of National Asphalt Pavement Association from its HMAT Magazine, November/December 2007.
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