Bettis Asphalt & Construction was looking for a way to speed up production on their 8 large heating and milling drones that form an asphalt-paving convoy almost 700 ft. long. These units heat and mill the existing asphalt surface, add an asphalt rejuvenation emulsion, and then replace the asphalt back on the road.
This process extends the road’s life by eliminating cracking and rutting, and recycling 100% of the existing materials—while simultaneously reducing the environmental impact associated with the heavy trucks used in conventional overlays. It uses 8 direct fire boxes to generate the heat required to soften the existing surface—so all of the equipment works in an environment of extremely hot temperatures.
Bettis also wanted to reduce mechanical down time associated with equipment exposed to high temps because in the asphalt-paving business, time is critical. The paving season lasts May 1 to October 1 every year, so it’s important to optimize as many daylight hours as possible. As a result, crews work dawn til dusk. This puts tremendous pressure on the equipment, which already operates under extremely stressful heat conditions—since propane burners in the direct fire boxes can reach up to 1200° F.
Last year, the team at Bettis redesigned their hot-in-place mobile equipment to speed up production and meet critical time goals set by their customers, like KDOT—but had difficulty finding mobile hydraulic gearboxes and motors that could stand up to the extreme operating conditions. James Campbell, Superintendent of the Hot-in-Place Recycle Division at Bettis Asphalt, worked with David Leffert at IBT Industrial Solutions to find an answer.
“Downtime with these vehicles is critical,” said Leffert, a Fluid Power Specialist at IBT. “They’re running a train of 8 vehicles in a 0.10-mile-long train, so if one of them breaks down, they all have to stop—wasting valuable time on the road.”
After many hours of analysis and research, Leffert recommended an entirely new drive chain design—complete with hydraulic motors, gearboxes, and sprockets, supplied by Young Powertech, Martin Sprocket, and Diamond Chain.
“Bettis is one of only 2 or 3 companies in the U.S. that do this type of work,” Leffert said. “We had to be very creative in how we approached the design of this system. Our goal was to find mobile hydraulic motors and gearboxes that could withstand one full season of extreme abuse,” adding that past motors had not lasted a full season.
With the exception of one or two minor replacements, Campbell said that the new motors and gearboxes have “significantly reduced the number of breakdowns in the last season.”
“This year, we were able to complete all of our new projects on time,” Campbell said. “Overall, we had about a 60% increase in speed of production over last year’s season. Altogether, that’s a significant improvement for us.”
Campbell added that while the sustainability and reliability of the equipment has improved dramatically, they are still tweaking the custom-designed hot-in-place recycle drones to see where they can improve for next season.
“David didn’t just order new parts, he spent many hours analyzing our whole hydraulic system to redesign and improve it,” Campbell said. “He brought an intellectual level to the partnership. We needed someone open-minded to dig into the details and work closely with multiple suppliers to design a custom mobile hydraulic system that would meet our needs.”