Denver Crushes RAP Tons
BY Astec Mobile Screens
Operating in the middle of the bustling city of Denver, Colorado, municipal crews need to make the most out of their reclaimed asphalt pavement (RAP) enterprise while taking up the least amount space. It’s an issue any asphalt producer is familiar with. Here’s how the City and County of Denver handles it.
Sustainable Sizing
Doug Legg, manager with the City and County of Denver, discussed the judicious use of space: “We’re [operating] inside the City of Denver, so property was very limited. To solve that problem, we looked for a machine that could feed, crush and screen all on one chassis to keep the overall footprint compact.”
Legg also considered equipment’s ability to run off of clean energy. After selecting the ProSizer® 3600 plant from Astec Mobile Screens, the crew set up a genset to run the unit.
Legg said, “We operate off a 500kw genset. It is located about 120 feet to the south of the plant, which keeps it out of the dust area. In the future, we can switch that to run it off a transformer.”
Legg also added that, because the equipment is run using electricity, they don’t have to worry about oil dust plugging and overheating engines.
From left to right: Mike Caldwell of KPI-JCI and Astec Mobile Screens; Doug Legg of City and County of Denver; and Eric Smallwood of Power Motive Corporation shared their experiences increasing recycle.
In addition to the small footprint and operating using electricity, the City and County of Denver also had specific operational requirements. Legg explained that a capacity of 250 to 300 tons per hour was a must-have for the project. Eric Smallwood, aggregate sales manager for Power Motive Corporation, worked closely with Mike Caldwell, regional sales manager for KPI-JCI and Astec Mobile Screens, and the City and County of Denver to help address the City’s concerns and necessities for equipment selection.
“Production capabilities were a strong driver,” Smallwood explained.
Before the City and County of Denver began processing its own asphalt, the material was going into the asphalt plant uncrushed. “About two years ago, we looked into crushing the RAP before it went to the asphalt plant,” Legg explained. “We found that by crushing the RAP, we could be cost effective, potentially recycle more material and recoup some of the [binder] out of the asphalt. That’s when we started the process of looking for the right plant for our application.”
Legg attended CONEXPO/CON-AGG 2017 in Las Vegas, Nevada, Caldwell said: “We met Mr. Legg at ConExpo 2017, where we started talking about the plant. When the City put out a bid, I believe it was the summer of 2017, we put in our bid, they liked it, and we won the order.”
In the end, the team came up with the solution that could help the City and County of Denver, which does much of its own pavement maintenance work.
“From start to finish, we rotomill our own streets, bring the millings to this yard, process them through the ProSizer 3600 [plant], and haul them across the street to our asphalt plant, which is a 300 tons per hour double-drum,” Legg said.
While Legg and the City and County of Denver have large crews working in street maintenance, there are usually only two people operating the ProSizer 3600 plant. With a small team and limited experience, operating the new machine was unfamiliar territory—at first.
“The ProSizer [plant] has been very easy to learn and operate,” Legg said. “The crew was up and running with the machine within two days of it being set up.”
Smallwood added, “We began operating this plant in April of 2018. So far, the City and County of Denver has stayed consistent in the 250 to 300 tons per hour range…The City needed a plant that could kind of be a jump start that they wouldn’t have to run every day, all day, seven days a week. They can keep up with their aggregate demands, working four, 10-hour shifts with minimal issues.”
Cooperation with Contractors
While the City and County of Denver’s street maintenance crews, which gives 242 full-time jobs to workers in the area, are part of internal crews, the City and County also provides asphalt to an outside contractor. “We produce, on average, 250,000 tons of asphalt per year,” Legg explained. “…and we provide asphalt to an outside contractor, contracted directly with the City and County of Denver…”
Smallwood added, “The City and County of Denver is a valuable customer. We appreciate everything they do. They are environmentally aware and support the asphalt industry greatly. Doug and his team are very heavily involved with all the local asphalt associations and support the most recycled product in the world.
“We would like to see the city earn a strong return on investment with the ability to introduce more crushed product into their asphalt plant,” Smallwood continued.
In the next year, Legg, Caldwell and Smallwood anticipate the City and County of Denver to see a return on investment and produce up to 30 percent recycled mixes, in addition to other environmentally responsible goals.