Better Roads

May 2012

Better Roads Digital Magazine

Issue link: https://read.dmtmag.com/i/85916

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HighwayContractor by Dan Brown, Contributing Editor To expedite production, Koss ran two belt placers ahead of the paver (right). The fi rst placer is partially visible (left). Make it Last and Make it Smooth A Kansas project delivers. The paver pushed only a small head of concrete, which made it easier to achieve excellent smoothness numbers or more than 30 miles, Interstate 70 in western Kansas was worn out. It was a full-depth asphalt pavement; sec- tions ranged up to 20 inches deep. The most recent asphalt treatments had lasted just five to seven years, says Andrew Gisi, geotechni- cal engineer with the Kansas Department of Transportation (KDOT). The state wanted something that would last longer, so KDOT chose a 6-inch bonded concrete overlay – 1.45 million square yards of it throughout nearly 31 miles. Last year, Koss Construction milled out 6 inches and slipformed two projects with concrete on 15.1 miles of four-lane inter- state. Including shoulders, the two projects totaled 725,000 square yards and cost $20.1 million. This year, Koss will mill and pave two more similar projects on I-70 for a total of 727,000 square yards at a cost of $21.9 million. F Koss' smoothness numbers last year were remarkable. Using a Guntert & Zimmerman S850 four-track paver to pave 30 feet wide, the contractor averaged just 8.5 inches of deviation per mile from a zero blanking band over the two projects. What's more, the Missouri-Kansas Chapter of the American Concrete Pavement Association (ACPA) gave Koss the "Smoothest Day Paving Award" for a 4,500-foot section on which the contrac- tor hit just 5.4 inches of deviation. On every section of concrete pavement last year, Koss earned a smoothness incen- tive from the state. To earn the maximum smoothness incentive, Koss had to achieve 6 inches or less of deviation per mile. The Colorado Department of Transportation (CDOT) is an especially important player in the Kansas situation, because KDOT used Colorado's pavement design criteria and system in designing Better Roads May 2012 5

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