Minnesota Contractor Improves Efficiencies and Productivity with Asphalt Milling Tool
BY LeRoy Hagenbuch
Asphalt milling—also called cold planing, profiling or grinding—to extend the life of pavement on parking lots, roads and bridges is far from glamorous. Often completed in the heat of the summer and amidst traffic, the application can be slow and maintenance-intensive due to the extremely physical nature of the work.
The method of removing and replacing the existing surface layer of pavement to a certain depth while leaving the sub-surface intact is a practical and effective way to extend pavement life. Project owners often choose it as a cheaper alternative to demolition or repaving. With asphalt pavement’s status as one of the oldest urban development technologies still in use today, some contractors seek alternatives to traditional surface milling technologies.
Searching for Something New
FPI Pavement Contractors Inc., a privately held asphalt company based in St. Paul, Minnesota, has performed various road restoration and construction jobs since 1995, ranging from parking lot design and resurfacing to mill/overlay and crack sealing. As the company grew, so did its project portfolio and scope of work. The company now offers demolition, bumper installation, striping, concrete work, utility construction and improvements, drainage systems, and site grading, to name a few, to meet the growing needs of its customers. Today, asphalt paving is FPI’s core specialty. About 90% of its asphalt paving business consists of performing asphalt milling and overlay work in commercial parking lots in the Twin Cities.
Until recently, when performing mill patching, paving, dig-out of asphalt chunks and patching work, FPI’s crews dealt regularly with the limitations of the carbide picks found on conventional asphalt milling attachments. The company’s existing asphalt milling tools required tooth—or carbide pick—replacement as often as twice a week to maintain performance. The milling machine’s teeth also required lubrication at cumbersome intervals, further slowing down projects. Additionally, FPI’s asphalt milling tools often left behind a rough, jagged milled surface that visibly showed through any new layer of compacted asphalt. These surfaces needed to be fixed, costing the company time and money.
“The downtime we experienced due to constant delays and rework ate into our productivity,” said David Mathis, a foreman at FPI. “We knew that we needed to invest in a piece of equipment that we could count on to maximize production and keep up with our demanding workload.”
As a small company, FPI needed to be resourceful and find an asphalt milling technique that was both reliable and could ensure that they could execute pavement restoration projects on time and with a polished finished product. Their search led them to Rolling Wedge LLC, based in Peoria, Illinois. The company featured its milling tool at the World of Asphalt conference.
The manufacturer displayed a Rolling Wedge milling tool meant to address the unique asphalt milling challenges faced by companies like FPI. FPI was using cold planers or milling heads with milling drums that were equipped with carbide picks. They mounted these drums on skid steers or similar host machines for asphalt milling. Rolling Wedge milling tools are designed to replace the traditional carbide picks on these drums for improved asphalt milling efficiency.
These tools are uniquely mounted to milling drums in lieu of traditional carbide picks. Rolling Wedge milling tools utilize a wedging-lifting action, placing concrete and asphalt in tension to mill the material as opposed to the crushing percussion action carbide picks traditionally apply in road milling. When put in tension, material such as concrete has just 20% of the tensile strength of its compressive strength, which allows the milling tool to break the material apart more easily. As a result, the Rolling Wedge milling tool is more energy efficient than traditional methods, which saves on fuel costs. The milling drum’s forward milling speed is dependent on the hydraulic system of the machine it is attached to, with typical forward milling speeds of between 8 to 12 inches per minute.
FPI was so impressed by the Rolling Wedge milling tool drum on display at World of Asphalt that the contractor brought one of its mechanics to the event the next day to learn more. They soon scheduled a trial of the equipment and were quickly convinced to outfit all their milling machines with new Rolling Wedge milling tool drums.
Filling a Need
Today, FPI owns several Rolling Wedge milling drum widths to execute the wide range of their projects more efficiently. The contractor utilizes planers or milling heads equipped with Rolling Wedge milling tool drums operated by Bobcat compact track loaders and skid steers. Crews typically arrive on site with a selection of 18-inch, 24-inch and 40-inch width milling drums. The smallest of the drums (18 and 24 inches) are ideal for seam repair while FPI often uses the 40-inch milling tool for overlaying hot-mix asphalt or profiling around concrete curbs. FPI can easily adjust the milling depth to fit specific project needs—most often 2 inches, but anywhere from 0 to 4 inches.
In Mathis’ words, FPI saw a “night and day difference” both in how long the Rolling Wedge milling tools lasted and how quickly they could be changed compared to traditional carbide picks. The Rolling Wedge milling tool hardened steel and carbide-tipped teeth lasted longer than traditional carbide picks and could be replaced in as little as 20 minutes rather than the previous one to two hours, according to the contractor. Additionally, with Rolling Wedge milling tools, FPI went from replacing carbide picks once or twice a week to a replacement interval of one to three months. The new Rolling Wedge milling tool drums didn’t require water cooling or lubrication and asphalt didn’t stick to them. Additionally, there is no heat generated in the asphalt or concrete milling work.
“With Rolling Wedge milling tools, we’re able to complete milling projects faster and with greater precision,” Mathis said.
FPI benefited from the Rolling Wedge milling tool’s quality of output. The milling tool created a uniform and consistent surface quality thanks to the drum’s ability to produce a more stable base than what’s achieved with percussive planing forces. Its forces leave no ridges or visual abrasions to mar the finished, compressed asphalt. The improved Rolling Wedge milling tool quality allowed the crew to be more efficient by not having to go back and repave with hot mix to smooth ridges that may show through the surface.
“With carbide picks, you had to constantly go back and redo it, which takes extra time to make sure it’s milled properly,” Mathis said. “In our line of work, you can’t afford to have anything slow you down.”
Though the work is tough and unforgiving, FPI finds pride in a job well done. This process is now easier thanks to new methods redefining how some contractors complete asphalt milling applications.
For more information, contact LeRoy Hagenbuch, Rolling Wedge at (309) 322-1600, firstname.lastname@example.org.