FAST Process is three times faster. (Photo courtesy of E.J. Breneman Inc.)
FDOT bid a 6.2-mile section of U.S. 27 last October near Tampa requiring the use of NovaChip a paving process that places an ultra-thin coarse-aggregate hot mix over a special polymer-modified emulsified asphalt membrane. The Tampa office of APAC-Florida Inc. won the $2.9-million U.S. 27 contract and will begin work this spring. FDOT plans to use this stretch of road in south-central Florida to compare NovaChip with its current mix, the open-graded friction course. The project has five test sections.
NovaChip is applied by a special paver that uses an emulsion spray bar 1 ft in front of the hot mix screed to apply the special 140°F emulsion membrane at a rate between 0.15 and 0.25 gal per sq yd. Unlike traditional tack coats, the membrane is not deformed by tires and breaks almost immediately on contact with the 300°F hot mix. The reaction forces the polymer membrane into any voids or cracks in the roadway.
The process is completed in one pass with the paver moving three times the speed of traditional pavers. The pavement cures quickly, allowing the road to be opened to traffic almost immediately after compaction. The new surface allows water to drain off the road while providing a watertight seal beneath.
"The advantage from a construction standpoint is that the polymer-modified membrane and hot mix can be placed in one pass," says John De Martino, NovaChip's national manager. "The speed of the system allows us to place up to six lane-miles a day."
A French company, Screg Route, invented the process in 1988. It was tested in Texas and Alabama in 1992 and has since gained momentum in 38 states. The largest NovaChip job to date is 100 lane-miles on North Carolina's Interstate 40. A 170-mile job north of Dallas on I-35 this spring will break that record.
FDOT let its first NovaChip project in July 2001a 2-mile stretch on I-75 in Hillsborough County. Subsequent studies at the University of Florida emphasized raveling (the loss of aggregate in the mix), rutting and cracking. Cracking is the most common in Florida. The U.S. 27 project will focus on field performance.he Florida Dept. of Transportation is testing a fairly new asphalt paving process that, if implemented, might eventually save some of the nearly $5 billion that the agency spends annually on resurfacing 40,000 lane-miles of roadway.