Highway Contractor: “I would like to Thank….”
Essentially, this only left six hours to pave because of the time required to mobilize and demobilize traffic control devices and to stripe the pavement at the end of the shift.
Even though it was a high-production operation, safety came first, Miller said. The project was completed, under heavy traffic, with no accidents involving the construction operations. “On a project like this one, we have a number of safety procedures to plan and set up, and we make sure that we have the discipline to follow them,” Miller points out. “We had safety meetings every night before work began and discussed in detail the objectives for success, and made sure that everybody knew the stopping and starting stations every night. At Orlando Paving, safety is our culture and we are dedicated to protecting our personnel as well as the traveling public. Working safely is a matter of good common sense, but you need to have the commitment to use all the right procedures and protocols.”
Three pavers are the charm
Operating three concrete pavers helped this contractor gain time and meet the schedule for a three-mile road construction project in St. Joseph, Mo. For Loch Sand and Construction Co., Maryville, Mo., the Route AC project on Riverside Road won a 2008 Silver Award in the State Roads category for Excellence in Concrete Pavement from the American Concrete Pavement Association.
Approximately half of the 3-mile section was four-lane divided highway with two driving lanes plus shoulders on each side. The remainder of the project was 56 feet wide including shoulders, said Rob Loch, treasurer and equipment manager for Loch Sand and Construction.
“We had a hard winter and we ran into subgrade issues, which put us behind schedule,” Loch says. “So we were looking for any way to pick up some time. Bringing in the three pavers helped expedite the paving work and complete the project in early November, before the season ended.”
Running the three pavers precluded the need to change widths on one concrete paver, which saved at least a week, Loch says. The contractor used one Gomaco 2800 working 20 feet wide, another Gomaco 2800 working 24 feet wide, and a Gomaco Commander III to slipform an 8-foot shoulder. The 20-foot-wide paver slipformed the variable median section in two passes. Meanwhile, the 24-foot paver slipped the divided highway section.
The project included some 33,000 square yards of 9-inch-thick doweled concrete pavement and 14,500 square yards of 6-inch-thick concrete shoulders. How was the smoothness? “We averaged 27.3 inches of deviation per mile from a zero blanking band,” Loch says. Anything less than 30 inches qualified for 100 percent pay.
The keys to smoothness were placement of a sound subgrade and base, an excellent track pad, a carefully set stringline and experienced paving crews, Loch says.
A wet and plastic subgrade proved to be one of the project’s major challenges. “We removed a pavement on the north end of the job, and placed shot rock to stabilize the area,” Loch says. “We also ran into springs of water, so we installed a system of French drains to carry away excess groundwater.”
The value of electronic grade controls
Using a Roadtec Shuttle Buggy and electronic grade controls proved the keys to exceptional smoothness on a mill-and-overlay project in Hinesville, Georgia. APAC-Southeast of Savannah, Ga., won a 2009 Quality in Construction Award from the National Asphalt Pavement Association for pavement construction on SR 119 and SR 196.
The Georgia DOT specifies that a milled asphalt surface meet a smoothness requirement of 1,325 millimeters/kilometer — and the finished pavement must meet a spec of 1,025 millimeters/kilometer. “So we used our electronic grade controls on the milling machines,” says Robert Royal, area manager for APAC-Southeast in Savannah.
The project was 4.734 miles long, and APAC used two milling machines — a Roadtec RX50 with a Topcon System 5 and a Wirtgen W2000 with a Moba electronic grade control system. Milling depth was 1.5 inches, and APAC replaced that with 1.5 inches of new hot-mix asphalt.
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