The road to faster recycling
Traffic caused by local construction, especially while repairing new roads, can be annoying. As drivers bump across “uneven lanes,” construction workers direct them the wrong way through a roundabout or behind a huge, stinking asphalt truck.
According to beyondroads.com, asphalt covers 94 percent of the roads in America. Although the constant deterioration of this pavement is inevitable, the materials used to repair and build rural roadways and main highways often comes from recycled products. Many states have been using recycled materials in pavement for decades, and increased technology has made using reclaimed asphalt pavement a better option for the environment.
Recycling pavement can also save time during road repairs, perhaps reducing the rage of impatient commuters.
A CDOT study on pavement recycling for the 2004 – 2005 construction year found almost 2 million tons of recycled pavement was used as base course, shoulder material or other structural aspects of concrete asphalt within Colorado.
Stacey Stegman, Director of Public Information for the Colorado Department of Transportation (CDOT), explains that there are no federal or state mandates regarding pavement recycling or the use of recycled material in construction – but it is a common practice in the state.
“(CDOT is) very committed to recycling as long as it makes sense from an engineering and environmental standpoint,” Stegman said.
Elam Construction in Edwards does use reclaimed asphalt as an aggregate. Neither they nor Asphalt Specialist and Supply Inc. in Eagle use any on-site reclamation techniques, however.
On-site recycling isn’t very common in Colorado, but it can save a tremendous amount of time and energy during road repair and construction. Pavement can be recycled on-site in a surprisingly quick procedure.
Full depth reclamation, or FDR, is one of three on-site recycling methods, along with hot in-place and cold in-place recycling.
According to figures posted by the Portland Cement Association at cement.org, full depth recycling requires only 12 trucks compared to 180 trucks to construct a new base, which means 300 tons of new roadway material and 500 gallons of diesel fuel compared to 4,500 tons of new material and 3,000 gallons of fuel.
Recycling asphalt emerged in the 1970s along with the recycling of glass, rubber, plastic, roof shingles and other waste products in construction.
Today, asphalt pavement is the nation’s most-recycled material – more than 70 million tons find new life each year, which is 80 percent of the asphalt removed during widening and resurfacing projects, as indicated by the National Asphalt Pavement Association. This is a staggering percentage compared to the recycling rates of municipal solid waste. The Environmental Protection Agency found 48 percent of paper, which constitutes the bulk of the MSW waste stream, and 44 percent of aluminum cans were recycled in 2003.
Tom Clayton, program manager at The Colorado Asphalt Pavement Association (CAPA), compares FDR to rebuilding a house, starting with the foundation and working up to the roof. The process repairs the roadway up to two feet below the surface and makes a noticeable difference in what drivers see and feel on the road.
FDR guarantees a smoother surface due to the decreased amount of construction traffic, Clayton said. Plus, the entire recycling and paving procedure can be accomplished with a few machines making one pass.
Although on-site recycling methods are not widely used in Colorado, the use of materials that contain recycled content is commonplace and asphalt contractors often independently initiate its use.
“The asphalt industry is the number one recycler in the nation, so we don’t have to encourage anybody,” Clayton said.
“There are asphalts out there being mixed with 70 percent recycled materials,” which means virgin materials make up only 30 percent of the asphalt, he added. Asphalt in Colorado, however, usually contains between 25 and 35 percent recycled materials. Clayton attributes this disparity to the usual migration of trends within a huge industry.
“We haven’t got to that point in Colorado,” Clayton said. “It hasn’t happened yet.”
A decrease in construction traffic along with a decrease in unused reclaimed asphalt could mean shorter construction waits for the traveling public.
Those caught waiting in construction traffic can hope word of on-site recycling travels quickly to the West.
– Chris Black can be reached for comment at email@example.com.
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