Better Roads Digital Magazine
Issue link: https://read.dmtmag.com/i/119545
like a road stone mixed with cement, and it���s placed with an asphalt paver,��� says Sawin. ���That���s really the only way to place this stuff, is with an asphalt paver, because it had to be drainable and it sets up hard ��� almost as hard as concrete. The top size aggregate in that material is 3/4 inch (0.75).��� Manatts mixed the cement-treated base with their nearby concrete plant ��� a CON-E-CO plant with a 12-cubic-yard drum. ���We had very strict guidelines on the compaction of the cement-treated base,��� says Sawin. ���They wanted it strong and compact, but they didn���t want it too dense because they wanted it to be drainable. We followed it with three roller passes, using a BOMAG roller and a double-drum Hamm roller. Next Manatts placed the engineering fabric. It serves as a bond breaker, to assure that the concrete pavement does not bond with the cement-treated base below it. And ���nally, the contractor paved the taxiway using a GOMACO GHP-2800 concrete paver working 18.75 feet wide. ��� Taking it to the Bank F aster production brings more dollars to the bottom line. That���s why contractor Tim Hokanson is so pleased that he recently bought a Topcon grade control system for his John Deere 750K dozer. Traf���c control was the major challenge of the 3.1-mile Four Corners North project, says Hokanson, a vice president with A.M. Welles Inc., Norris, Mont. The $11.5-million project called for widening U.S. 191, just south of Bozeman, Mont., from two lanes to ���ve, including a turning lane. And the state of Montana required that Welles maintain two-way traf���c through the project during construction. ���We couldn���t use a pilot car or switch over to one-lane traf���c,��� says Hokanson. ���We always had to be building ahead of ourselves A.M. Welles Inc.���s Hokanson figures that the Topcon system will pay for itself in two years. ��� giving two-way traf���c a place to go on one side while we worked on the other side. production by about 20 percent, Hokanson estimates. Welles ���That���s one of the main reasons we decided to buy a John nearly completed the project before winter in 2012. He says Deere 750K dozer with another Topcon grade control systhe Topcon system slashed about a month from the time it would have taken without one. In just 100 days, the contem on it.��� tractor moved 350,000 to 400,000 cubic yards of material Hokanson already had one Topcon grade control system for the project. mounted on a Caterpillar dozer. By adding the John Deere 750K with automated grade control, the contractor could ���We found that the Topcon system is really good,��� says excavate subgrade in one place while ���lling with base Hokanson. ���It saves a lot of time. When we saw how well course material and getting ready for traf���c in another. the ���rst one was working, you could tell that there was a huge amount of savings to be made with another one. That���s The Topcon automated grade control system sped up his Better Roads April 2013 11 HighwayCon_BR0413.indd 11 4/1/13 3:29 PM