In the shadow of the famous Daytona International Speedway, the Wirtgen Group’s “Three Amigos” of Hamm oscillation “Ozzie” rollers, Vogele America paver and Wirtgen mills were helping Daytona Beach International Airport in Florida to beat rising groundwater that was threatening its paved surfaces and operations.
The airport is using taxiway and runway asphalt overlays and rebuilds to raise the surface of critical paved operating surfaces, in effect raising the pavement well above the water table.
“Heavy rains have put us back five to six weeks behind schedule,” said Fred Iannotti, purchasing manager, Halifax Paving Inc. “And rain is the reason for this job; the groundwater table is so high that it has risen into the limerock base of the taxiways, and cracked them apart.”
“We cold-milled the existing asphalt and base down 24 inches, and then came back with a 12-inch stabilized base, seven inches of limerock, seven inches of black base with one-and-a-half inch top size stone, and four-inch P-401 surface course,” said Frank Jones, paving superintendent of Halifax.
The firm was working on a taxiway in late summer, but large areas of cracked runway pavement awaited restoration.
’Three Amigo’ Contractor in Florida
Milling of the existing asphalt was done by two Wirtgen machines, working in unison, a W 2000 and a W 2100. They were joined by two Hamm HD O120V Oscillation rollers, a Hamm 3410 soil compactor, and a Vogele America 1110 WB asphalt paver, predecessor to today’s 2219W.
Briggs Construction Equipment is Halifax’s distributor.
“We’re the first Florida company to achieve ’Three Amigo’ status,” Iannotti said. “We began with the Wirtgen milling machines, and from our experience with those we acquired the rollers, and now we have the Vogele America paver.
The 35,000-sq.-yd. (29,264 sq m) project involved 20,000 tons (18,000 t) of hot mix asphalt, and 18,500 cu. yd. (14,144 cu m) of base. Specs for the base course required 98 percent in the mat, and 97.3 percent on the joints.
“Because of its unique design involving larger stone, the base course was real hard to achieve density,” Jones said. “Using conventional rollers we were having trouble getting density; that’s why we went with the oscillation rollers from Hamm. The oscillation rollers got density on the first lift of base course with two coverage passes — oscillation and vibratory — and on the second lift, with one coverage pass.”
That’s a lot better performance than Halifax was used to seeing.
“Normally, even on our highway mixes with conventional rollers, we would have to use four to five coverage passes,” Jones added.
“Once the airport owners had seen the numbers we were getting off the cores, they were ecstatic that we’re getting compaction that quick.”
“In fact, we were getting so far above the requirements, that we had to ’back off’ what we were doing,” Iannotti said. “Our target range was 97.3 to 99.2, and were getting 100, 101, even 102.9. At the airport’s request we had to back off some of the coverage passes to get back into our target range.”
The airport was concerned that oscillation rollers getting compaction into the very high density range would fracture the aggregate in the mix, but nonaggressive oscillation compaction will not shatter aggregate, as Halifax’s Jones found. “At those densities, it’s not shattering the stone at all,” he said.
Investigating Oscillation Compaction
Halifax’s acquisition of the Hamm oscillation rollers was the result of a good deal of investigation and research.
“I’d been following oscillation compaction in the industry trade journals for about three years,” Iannotti said. “For two years we had wanted to do a demonstration but machines tended not be available when we had an application requiring more efficient compaction. We were able to see it work a week before the airport work started, and ’Wham,’ it cured our problems on that job in advance of the Daytona airport job.”
Unless two adjoining lanes are paved in tandem, compaction of cold joints between lanes is nearly always problematic. But oscillation compaction is so efficient — even with cooled mats — that Halifax has been able to achieve density on cold joints just as well as the warm mats.
“Originally we were having joint compaction problems, but the Hamm rollers have brought the joints into spec, even when the mix has cooled outside its target temperatures,” Jones said. “We heard the state of Colorado has had the same experience in solving its highway joint density issues.”
The same benefit applied to a potentially costly downpour that cooled fresh hot mix, but Halifax still was able to get density on it.
“We had a situation where we had paved a shopping center lot, and at day’s end two loads of asphalt had been rained on heavily, and sat there all night,” Jones said.
“There were problems with roller marks. We came back the next day about 10 a.m., when the sun had heated the asphalt, put the “Ozzie” on it, and it actually compacted the asphalt another quarter of an inch. It was amazing, that’s all I can say.”
The ability to salvage cold loads of hot mix via oscillation technology can really impact a firm’s profitability.
“It’s great for a firm’s bottom line,” Iannotti said. “We’re still realizing what we can achieve with these machines. Once we get several of these jobs under the belt, we will have a better idea of what we can expect.”
Iannotti said the firm’s purchase decisions also consider Wirtgen’s reputation in the field.
“I base an awful lot of the purchase decision on Wirtgen’s reputation, even before Briggs, back to when we bought our first milling machine,” he said.
“Any time we had a question, there was someone who could answer it. They designed it, they built it, they could tell you exactly where to look and what to do. And parts availability was never an issue.
“Based on this experience, we stepped into the Hamm rollers with Briggs,” Iannotti said.
“In advance of the Ozzies, we bought several 3000 Series soil rollers, and that input served us well in buying the Ozzies. Following oscillation technology in the trade magazines also made us want to try them. My reputation is based on what I do, and I put 99.9 percent faith in the Wirtgen Group name as far as the paver goes.”
Parts availability was an issue for John Van Seeters, Halifax facilities manager, but that potential problem was quelled.
“Parts availability was a concern at first, but not now,” he said.
“We haven’t had any problem with the Vogele paver, and when we bought it, they came and went over it step-by-step with us, explaining everything, which most companies won’t do. All my mechanics and field men came in, and we could see that it was a well-built machine with easy access.”
“We demo’ed the paver extensively, as we already had six of another brand of paver, and it was a big deal for us to move to another brand,” Iannotti said.
“But so far everything has worked out well, we’re happy, and are getting the service and backup we need with Briggs.”
(This article appears courtesy of “Wirtgen Technology” magazine.)