The milled material is loaded into haulers and transported to Reliable’s Waugh Chapel Plant, where it is crushed into coarse and fine aggregate stockpiles. A Hitachi ZX470LC-5 excavator then loads the crushed material into trucks, which transport it
It was only recently John T. Baldwin Jr., operations manager at Reliable Contracting Company Inc., noticed that the Hitachi ZX470LC-5 excavator and its fleet of four haulers were making a dent in the milled asphalt pile that’s been sitting at the company’s Waugh Chapel Plant for nearly two decades.
The demand for crushed asphalt has skyrocketed as the use of recycled materials in the construction of new pavements has reached record-high levels.
According to a survey conducted by the National Asphalt Pavement Association under contract to the Federal Highway Administration, about 66.7 million tons of reclaimed asphalt pavement (RAP) were collected in the United States during 2011 for use in new pavements. That represents a 7 percent increase from 2010 and a 19 percent increase from 2009.
Reliable, a commercial and residential contractor based in Gambrills, Md., has been an innovator in the use of recycled asphalt and has noticed this trend firsthand.
“When the county and the state accepted the use of these recycled materials on its projects, it became much more popular,” Baldwin said. “These types of recycled materials not only drive down costs, but also address the issue of how to dispose of the mountains of roadbed material milled from highways each year.”
How it Works
The process begins when asphalt is milled from roadways for the purpose of reconstruction, resurfacing or to obtain access to buried utilities. The milled material is loaded into haulers and transported to Reliable’s Waugh Chapel Plant, where it is crushed into coarse and fine aggregate stockpiles. A Hitachi ZX470LC-5 excavator then loads the crushed material into trucks, which transport it to the asphalt plant.
When reclaimed asphalt pavement and shingles are processed into new pavement mixtures, the liquid asphalt binder in the recycled material is reactivated, reducing the need for virgin asphalt binders.
“The process essentially lets us use the old roads to create new ones,” Baldwin said. “Our recycled products can be used as a subgrade to pave on, and as much as 35 percent of the recycled asphalt can be used in the production of new asphalt. This makes it much more affordable for developers. It’s truly a win-win for everyone.”
Production and use of recycled materials at Reliable’s two hot-mix plants have seen significant increases over the last several years. In 2011, sales of recycled materials peaked at more than 250,000 tons, making Reliable one of the largest recyclers in the area.
The increased demand for recycled materials has made it possible for Reliable to run an excavator such as the ZX470LC-5 at the plant.
The machine is paired with a fleet of four 22-ton trucks and moves roughly 3,500 to 4,000 tons during an eight-hour shift. This has become a vital factor in Reliable’s ability to keep up with the demand for recycled asphalt.
“We really like the comfort and responsiveness of the Hitachi excavators,” Baldwin said. “Power and fuel consumption are also big factors. In fact, it was Hitachi’s fuel consumption that made my dad, Jack Baldwin, switch from another brand about 20 years ago.”
Reliable Contracting Company Inc. is serviced by Elliott & Frantz Inc., Jessup, Md.
This story was reprinted with permission from Hitachi Breakout Magazine, First Quarter 2014 Issue.