New Cat profiler a solid performer for US contractor

The Cat PM622 Profiler has proved to be 50 percent more productive than previous mills for US contractor Tri-City Blacktop.Road construction is all about precision work and meeting deadlines. Not only must jobs meet tight specifications, they must also be completed on time.

Tri-City Blacktop, Inc. accomplished both of these goals at a milling job for the city of Bettendorf, Iowa, US.

A Tri-City Blacktop crew milled concrete at a depth of 2½-inches for the 0.8-mile Middle Road resurfacing. Milling was completed in four days. Cleaning and prepping the milled surface took another two days, and paving was finished in four days. In 10 days, one of the city’s worst streets became one of the smoothest.

A Cat PM622 Profiler helped the crew mill 5,600 square yards daily. With a milling width of 88 inches, the PM622 is 50 percent more productive than previous mills the crew operated.

“We’re able to make a wider cut, for one thing,” said Luke Carpenter, Field Superintendent. “We had high expectations for the PM622 on this job, and it exceeded them. We had a 4,000 square yardage goal every day, and we exceeded that every day that we milled.”

With an operating weight of 74,580 pounds and rated power of 630 hp, the PM622 easily milled the 2½-inch concrete layer. “We can mill with such precision with this machine. It doesn’t chatter, the tracks don’t jump. It handles tough jobs like this better than any machine that we’ve seen,” Mr. Carpenter said.

The Tri-City Blacktop crew milled within 1/8-inch of the specified depth. “The city doesn’t want us to get into the rebar that’s in the concrete, so they didn’t want us going any deeper,” Mr. Carpenter said. “We didn’t hit any rebar. It’s been a very smooth job.”

Meeting the milling specifications was also critical to keeping the existing hand-framed curbs intact. The city didn’t want the road height changed, which would have required curb replacement. Tri-City Blacktop met the specs, and new curbs weren’t necessary.

The PM622’s technology helped the crew complete milling quickly. “True zero for matching is stored in the grade control system. There’s never any second guessing. Once you get the machine set up, it’s always set up,” Mr. Carpenter said. “You can set down at two and a half inches and taper that out 30 feet to two inches and not have to do it manually. It will do a perfect taper every time.”

A highly skilled crew is necessary to mill at the rate that Tri-City Blacktop did on the Middle Road resurfacing project. “We’ve had this crew together for 20-plus years. They do a great job,” he said.

Sometimes you catch a break, too. Topography worked in favor of Tri-City Blacktop. “This job has some hills, and we’re using them to our advantage. Downhill, with the gravity, is helping us move a little quicker through the concrete,” Mr. Carpenter said.

Tri-City Blacktop successfully met a 0.25-inch over 10 feet bump specification. The crew used a Cat AP655F Asphalt Paver to place three lifts (1-inch sand level mix for crack fill, 2-inch intermediate lift, and a 1.25-inch surface lift). A total of approximately 6,000 tons of material was placed. The asphalt was produced at a Tri-City Blacktop plant three miles from the jobsite.

The PM622’s controls are similar to those on Cat pavers. “We’re all familiar with the pavers. Caterpillar did a really good job tying the two together. You can jump from one to the other without having any doubt in what you’re doing. Grade control is laid out the same on both,” added Mr. Carpenter.

And when the Tri-City Blacktop crew was finished with the job, a rough section of Middle Road was smooth driving—on time and with all specifications met.

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