While some businesses may consider too much work a problem, Pennsylvania asphalt contractor Glenn O. Hawbaker Inc. sees it as a good problem to have and recently proved its production crew at the company’s Pleasant Gap Asphalt Plant #1 (located near State College in central Pennsylvania) was up to the task. Glenn O. Hawbaker Inc. operates seven asphalt plants — five drum and two batch plants.
The Pleasant Gap Asphalt Plant #1 has been operating around-the-clock since June 6, except for Saturday nights and occasionally Friday nights. But come Sunday afternoon, the plant is up and running at full capacity.
The original CMI plant was brought on line in 1989 and updated with a new Maxam Drum in the spring of 2004, making it capable of producing up to 500 tph with up to 40 percent reclaimed asphalt pavement (RAP). The Maxam SOLO Drum is 10 feet, 6 inches by 44 feet long with 4 inches of insulation protected by a stainless-steel cover. It’s equipped with the Maximizer Exhaust Heat Recovery System, a new Hauck Eco-II Long Nose Burner that burns mostly recycled oil #5 and natural gas #2, and a new Impulse II Control System. The plant is supplied by five virgin cold feed bins and two recycled feeders with a Tel-Smith RAP Crushing System. Four liquid asphalt storage tans, capable of holding over 110,000 gallons of AC, and six silos, capable of holding over 1,400 tons of hot mix asphalt (HMA), provide the capacity to support four to five paving crews during the day with 2,500 to 3,000 tons of three to four different mix designs, along with the additional production needs of nighttime projects. The plant has been operating two 12-hour shifts, with each shift staffed by a crew of three, plus plant operator Travis Peters.
The Maxam SOLO technology produces exhaust gas exit temperature of only 200 degrees through advanced, high-efficiency flighting, which allows up to 50 percent reclaimed asphalt paving (RAP) content without superheating virgin aggregate, because the RAP is radiantly heated by the burner flame to 300 degrees (hot enough to remove moisture but not hot enough to reach smoke point), and the baghouse outlet temperature is automatically controlled at 225 degrees with the Maxamizer Exhaust Recovery Unit.
The heat recovery system captures exhaust temperatures exiting the drum at 180 to 200 degrees and then heats the gases to 225 degrees with a small burner before they enter the baghouse. This is accomplished with a flighting system that basically over-flights the drying drum to transfer more heat to the aggregate. This technology reduces the CFM and BTU requirements of the system, which translates into increased production of up to 20 percent and reduced fuel costs, as much as 5 to 10 percent per ton.
The advance counter-flow technology delivers greater fuel savings, higher production, increased RAP usage, safer baghouse operation and longer equipment life.
Gearing up production
The Pleasant Gap facility geared up production June 6 when the night paving crew working on the $43-million Centre County portion of Interstate 80 began placing 4,500 tons per night of 37.5mm, 15 percent RAP base course mix. Kurt Ross and his crew placed four lifts of base course (133,414 tons) to construct the 19-inch base for the 7-mile stretch of the highway. Hawbaker’s production and paving crews maintained the aggressive schedule for 20 days, using 24 tri-axle trucks to supply the project, which was located five miles from the plant.
Then on June 26, work on the Union County portion (50 miles from Centre County work) of I-80 began, with crews continuing to work around-the-clock, using 40 trucks per shift to supply the 28,637 tons of 37.5mm, 15 percent RAP base course mix required for the 4-mile stretch of the Union County project. Keeping pace with the two projects required 10 to 15 loads of liquid asphalt every 24 hours. With work well underway on the Union County, Ross’ paving crew moved back the Union County project to Centre County on July 5 to start laying three different lifts — two 3-inch lifts of 19mm intermediate/binder and a 2-inch lift of 12.5mm E (skid resistant) surface course mix — to complete the full 27-inch thick HMA mainline travel lanes of the Centre County I-80 project, setting a shift production and laydown record of 6,027 tons.