Atlanta, GA (October 1, 2001) — EZ Street Cold Asphalt Utility Repair
Technical Specs: 5 ft x 9,000 ft, Depth 4.5 ” Material: EZ Street Cold Asphalt Bulk Mix
When concrete fill won’t cure fast enough, contractor turns to cold asphalt product for surface course
By Sandy Lender
Creating and repairing a 9,000 ft (2,743 m) utility cut without disrupting traffic flow sounds impossible. Imagine the logistics involved in making a 300 ft (91 m) utility cut 4.5. ft (1.4 m) deep by 5 ft (1.5 m) wide, laying 12 inch (300 mm) plastic pipe, backfilling, pouring 10 inches (250 mm) of concrete, then paving with an asphalt mix between 8 p.m. and 6 a.m. Traffic’s headed toward the site in the morning, so you’ve got to be out of the way. The crews of Flint Paving Co., Atlanta, a division of Natcomm Inc., Houston worked with Georgia Department of Transportation (GDOT) officials to approve a plan for getting in, getting the job done and getting out of the way.
“Our project is approximately 9,000 ft (2743 m) of replacement,” explains Jim Smith, construction coordinator on the 12-inch (300 mm) bare steel renewal project for Atlanta Gas Light. “The gas line that we’re replacing is a 12-inch (300 mm) bare steel that was put into service back in the mid to late 1930s. This (replacement) is mandated by the public service commission.” Smith explains that the 12 inch (300 mm) plastic line that his company is installing is a medium high-pressure line that is placed about 4 to 4.5 ft (1.2 to 1.4 m) beneath the surface. “The standard procedure is to saw cut and remove the asphalt and dirt composition,” says Smith, “The DOT will not allow us to put spoils on the roadway, so we have to remove all this as we do it.” To get a smooth driving surface, Atlanta Gas Light accepted bids from contractors to perform the project.
Flint Construction won the bid, but the original specs were going to be difficult to work with, according to George Betzner, manager of Flint’s paving division. As Betzner explains it, combining about 10 inches (250 mm) of “high early concrete” with ‘a 2 inch (50 mm) hot mix asphalt (HMA) layer would have required perfect timing. “The problems that we had with the combined high early concrete and hot mix (being placed on) the same night were simply logistical,” says Betzner. He explains that crews had to let the concrete cure, then start up an asphalt plant, bring the mix to the site, lay it and roll it within a 10 hour window. “Anyone watching knows that pouring concrete, putting down asphalt and opening a road to traffic within a couple of hours leaves no room for error,” says Betzner. “Everything has to be perfect.”
In order to stay on schedule each night, Betzner had to have concrete in the ground by midnight so it would have a full six hours to cure before traffic was allowed on it. As he explains, putting a layer of HMA on uncured concrete is not an ideal scenario. “Our spreader box weighs 40,000 lb (18,144 kg),” says Betzner. “Obviously, curing concrete won’t handle that kind of weight.” Even hand-applying the hot mix left crews with the dilemma of how to compact without driving heavy rollers on the cut. Betzner found that his crews could use a cold mix, such as the EZ Street® product, as the top course at any time of the night, and not compromise the curing concrete beneath. To address time concerns, Flint Construction crews, with the help of representatives from the EZ Street Co., Miami, performed a test section for GDOT. They poured concrete into the utility cut, gave it some time to cure, then used a wheel loader to shovel EZ Street cold mix asphalt on top. After luting and raking, crews did light rolling to smooth the surface. “What the EZ Street did for us on this project was it allowed us to pour concrete,” says Betzner. “Then later in the morning, we’d take the roller and roll it, make it smooth, then breakdown traffic control and go away.” After the final night of utility replacement, Flint milling and paving crews completely removed and replaced the width of the affected lanes.
“The public sees a road that is repaired and, essentially, repaved the next day, with no disruption in the flow of traffic,” says Betzner. With a team producing a new product and a DOT willing to try it out, Flint Construction has the best of both worlds in this utility project. What could have been a logistical nightmare night after night has turned out to be a smooth operation. The project shows how teamwork and the right materials can get the job done successfully.
The return to traffic was carefully timed to avoid penalties.
Reprinted with permission from The Asphalt Contractor® magazine, October 2001.