Iowa Glasphalt Project - An Update of the Past Two Years*

*Many of you may remember hearing Merry Rankin from the DNR’s Energy and Waste Management Bureau speak at the Association Conference in Ames in 2001 about glasphalt. This article will update you on the activities that have occurred since then and how our membership has helped “pave” the way.

During a recent visit to the Landfill of North Iowa’s Education Center in Cerro Gordo County, a class of third-grade students found themselves fascinated with an aspect of the facility that most people take for granted. They were checking out the parking lot.

This is no ordinary parking lot, though. It’s made with glasphalt, a hot mix asphalt that uses crushed glass as one of the aggregate sources.

“Everyone who visits the Education Center is amazed at the “cutting-edge” concept of using broken glass for a surface like this,” noted Bill Rowland, education coordinator for the Landfill of North Iowa.

“The third-graders couldn’t wait for an explanation as to why the parking lot was so shiny,” Rowland said. “Once I explained what was in the asphalt, they spent the next ten minutes on their hands and knees, looking at, feeling and discussing the glass.”

The concept, developed in the 1970s and used successfully in Iowa on a few projects, hadn’t been used for years. But recently the Iowa Department of Natural Resources (DNR), in an effort to offer diversity in recycling options for glass, has resurrected the idea. With assistance from the DNR, the Iowa Department of Transportation (DOT), the Asphalt Paving Association, and a host of other partners, six pilot projects have been completed around the state within the past year.

In states such as New Jersey, where landfill space is in short supply, glasphalt takes on a more significant role. However, glasphalt hasn’t been used much in Iowa during the past three decades, mainly because of the amount of glass needed for large highway projects and because a significant percentage of glass can be recycled. Some types, however, such as fluorescent tube glass, have a limited re-use market, making them difficult to recycle. Additionally, current markets for other glass streams often fluctuate. The smaller quantities of glass needed for projects such as trails and parking lots makes glasphalt a nice option for diversifying local recycling efforts.

This has proven true for the six pilot projects that have taken place across the state. The Landfill of North Iowa used 32 tons of glass. Other projects in Charles City and Wellman, as well as a small trail at the Iowa State Fair, have offered another recycling option to over 100 tons of glass.

There is another unique aspect of glasphalt as a market for recycled glass. “Communities looking for new markets for recycled glass can use their own glass collected through recycling programs for local projects,” said Merry Rankin, glasphalt project coordinator for the Iowa DNR. “It’s a great opportunity to build community awareness.”

Such an approach was used in Cedar Falls, for example, where the city collected more than 70 tons of glass that was used in a trail near the University of Northern Iowa. A project in Ames also utilized city-collected recyclable glass.

“Glasphalt projects are a good example of balancing a recycling technology with an end application,” said Mike Heitzman, state bituminous engineer with the Iowa DOT.

Material and Mixture

Waste glass generally is divided into three types: container glass, windowpane (plate) glass, and tube glass. Most container and plate glass is readily recyclable, but often have fluctuating markets or, in the case of tube glass, markets may be limited. A primary advantage of glasphalt is that any glass type is suitable for its applications.

In practical terms, the glass is crushed and processed into a pure silica sand. Early DOT testing, conducted with the assistance of Metro Wrecking of Des Moines, specified the use of a product that would pass through a No. 8 sieve. This ensured a uniform particle size and passed all performance testing at DOT’s Central Laboratory in Ames.

Environmental concerns were addressed in testing, as well. The DOT tested the toxicity of the tube glass, the dust generated in the crushing process, and the concern for worker health at the hot asphalt production facility. No hazardous conditions were detected.

Under current specifications and intended use, this material is substituted into hot asphalt mix applications at a rate of 10% of the aggregate weight. These specifications are considerably different than initial mix designs of the 70s in which glass was substituted at a rate up to 50% at a spec considerably larger than the current No. 8 designation.

Working Together

The success of these glasphalt projects would not have happened without a great deal of cooperation between many partners. Along with the Iowa DNR, the Iowa DOT, the Asphalt Paving Association of Iowa, and Metro Wrecking & Excavating of Des Moines, these partners included:

Project	Partners
Landfill of North Iowa Drive-up recycling area/parking lot	Bill Rowland - Landfill of North Iowa Heartland Asphalt
City of Cedar Falls Recreational Trail	Ron Ahrens - City of Cedar Falls AsPro Weichers Construction Rampart Corporation
Iowa State University Parking Lot	Doug Houghton - Iowa State University Mannatt’s Inc.
State Fair Walkway at DNR Building	Merry Rankin - Iowa DNR Grimes Asphalt and Paving
City of Charles City Recreational Trail	Daryl Schmidt - City of Charles City Fred Carlson Company, Inc., L.L.C.
City of Wellman Recreational Trail	Max Lewis - City of Wellman LL Pelling Company

“Developing glasphalt has been a great example of diverse interests working together to find a mutually beneficial solution,” Heitzman said.

Rankin said the APAI has been an important partner.

“A special thanks goes to APAI and (Director) Mike Kvach for their support in offering us time to speak on the project,” Rankin said. “That’s what really started the ball rolling. Since that time APAI members have assisted us greatly through building awareness and getting projects down.”

The Future

Hopefully, the glasphalt pilot projects of the past year are only the beginning.

These projects called for the DNR, in conjunction with local agencies and solid waste management groups, to acquire the glass. Financial assistance from the DNR covered the cost of acquiring, crushing, and delivering the product to the asphalt paving contractor. The hot asphalt producer then handled the crushed glass like any other fine aggregate source.

If demand for glasphalt can be bolstered, then the cost of processing the glass will decrease to a point where it will offset the cost of landfilling or other recycling options. Once that happens, glasphalt will be in business.

“It is my expectation that the glass processing cost will eventually support itself without additional financial assistance,” Heitzman said. “When that occurs, Iowa will have a sustainable market for glass waste.”

If these pilot projects are any indication, the future is bright for glasphalt. Governor Tom Vilsack recognized the DOT with a 2001 Governor’s Environmental Excellence Award (special recognition in waste management) for its role in the pilot projects. Rankin said that based on response from partners, the outlook looks good.

“We’ve had a positive response from the paving industry and from local governments,” Rankin said. “We’re looking forward to forging ahead with glasphalt as an aggregate source and as a market for glass.”