Sometimes the solution to the problem can be found in your own backyard — or driveway — as was the case with the Delaware Solid Waste Authority (DSWA), Dover, Del. When the market for recycled glass fell into a slump, the DSWA found another alternative to make better use of the material.
Forming a partnership with Jerry's Paving and Tilcon Delaware, the DSWA decided to mix glass and asphalt to produce “glassphalt,” which then could be used to repave DSWA's administrative building parking lot.
According to the DSWA, brown, green, clear and mixed glass were collected from its 146 Recycle Delaware centers statewide. Ten percent glass was mixed with 90 percent other aggregates such as sand, stone and bituminous cement, then heated to form the glassphalt. Of the 400 total tons of asphalt poured into the DSWA's new parking lot, approximately 40 tons of it is glass.
A typical asphalt mix is 95 percent aggregate, with the remaining 5 percent comprised of liquid asphalt, the sludge that remains from refining oil and gasoline.
Glassphalt costs about the same and has the same life expectancy as regular asphalt — approximately 20 years, says Thomas E. Houska II, DSWA's chief of administrative services. “The Department of Transportation has used glassphalt in the past for base-coating but not for top-coating … and we wanted to see how the material would hold up. It's working out great so far,” he says.
“Contractors also found it easy to work with,” Houska adds. And the DSWA feels good “environmentally” because it is using a recyclable, man-made material that conserves the state's natural resources.
For more information on the DSWA and glassphalt project, visit www.dswa.com.