A tight timeframe was among the many challenges recently at Salt Lake City International Airport.
Granite Construction crews recently milled and resurfaced portions of the airport. Specifically, the project called for profile milling and resurfacing of the middle runway and all the taxiways. Crews removed 4 in. of asphalt during milling and replaced it in two 2-in. lifts. During the job, 80,000 tons were placed.
Specified tolerances were 2/100 of a foot, and the crews consistently hit or exceeded that goal.
It’s the job of Kyle Smith, project manager at Granite, to make sure the more demanding specification targets were achieved—and the penalties avoided.
The targets, of course, include meeting deadlines. That meant Granite crews had to be productive, despite the cold spring.
“We paved on some pretty cold days,” said Smith. “We had to get started.”
Starting early meant a better chance of finishing the job on schedule. But the cold weather could have put other specifications, particularly density and smoothness tolerances, in jeopardy.
It didn’t, in part because of Granite’s compaction efforts. The company used an echelon-paving process, which meant six asphalt compactors were used—three behind each echelon paver. Five of the six rollers used were Cat CB64s.
The CB64 features a five-amplitude vibratory system and provides the necessary punch on projects that require a heavy hitter. The Versa Vibe Vibratory system creates a “2-in-1” roller, for thick or thin lifts, and offers four amplitudes and two frequencies. The dual amplitude/dual frequency feature automatically matches amplitude and frequency, while the 50-50 weight distribution ensures consistent compaction coverage.
Granite crews took advantage of the multiple amplitude settings. “We set the amplitude at 3 for most of the project,” Smith said. “When conditions were tough we would set it at 4 to help with any issues we had.”
The amplitudes were adjusted based on results generated from test strips. “We adjusted the control settings and varied the rolling patterns,” Smith said.
The compaction efforts paid off.
“The rollers were able to hit hard enough to deliver the compaction efforts we needed, even in those colder conditions,” Smith said. “We never had incentive/disincentive problems with the rollers.” R&B
