Recycled Glass: From Post-Consumer Waste to Construction Material?
Those beer bottles you drink from while watching the football playoffs could one day end up as part of a bridge abutment, a poured concrete floor in a high-rise building or an insulating drainage layer in a green roof. In the nearer future, you could drive over them on a highway.
European countries including Germany and Denmark have been using foamed glass aggregates made from recycled glass as a lightweight filler in road construction and other types of civil engineering work for several decades. The United States is just starting to flirt with the material.
Foamed glass aggregates are made from 100 percent post-consumer mixed recycled glass, according to AeroAggregates, a recently formed Pennsylvania company that produces the material. The glass is ground into a powder, mixed with a foaming agent and then sent through a kiln to be softened. Bubbles form within the softened glass, creating the aggregates. They range in size from 0.4 inch to 2.3 inches and weigh about 15 percent of similarly sized traditional aggregates.
According to AeroAggregates, the material is a good insulator and is non-absorbent, non-combustible and resistant to rot, acid and chemicals. The company says its potential uses include everything from wastewater and storm water filters to artificial sports fields to bulkheads and retaining walls.
According to an article in the Philadelphia Inquirer, the biggest market may be highway projects. Transportation departments in New Jersey, Maryland, Virginia and New York are exploring the possibilities. PennDOT has used the material for a section of Langley Avenue near the Naval Yard in Philadelphia and will be using it for a ramp on I-95 in that city.
This isn’t the first time highway builders have attempted to use recycled glass in road construction. Glassphalt, made by including a small percentage of crushed recycled glass in asphalt mixes, has been tried in a limited number of projects in cities such as Baltimore and New York but never quite caught on due to various issues. AeroAggregates is banking on a different fate.
If used widely, foamed glass aggregates could be a boon to recycling operations in the United States. One of the biggest challenges for recyclers is sorting glass by size, color or type, but foamed glass aggregates can use mixed glass. Another issue for glass recyclers is lack of demand; some have to pay to get rid of their glass. A construction market for recycled glass could change the equation. That’s an idea worth raising a beer to.
Freelance writer Mary Lou Jay writes about business and technical developments in a variety of industries. She has been covering residential and commercial construction for more than 25 years.
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