What is Foam Glass?
Foam glass can go by a variety of names: foamed glass aggregate, foam glass gravel, or cellular glass. Whatever terminology is used, it’s a lightweight, thermally insulating aggregate made from post-consumer recycled glass. Whether it’s used as lightweight fill for civil projects, as thermal insulation underneath a concrete slabs or limecrete floors, or even as lightweight green roof fill, foam glass is an ideal building material to solve some of the construction industry’s most pervasive issues.
Since foam glass is derived entirely from recycled glass, it’s incredibly low embodied carbon and one of the most environmentally sustainable building materials on the market.
The Production Process of Foam Glass
Foam glass begins as post-consumer recycled glass. Glass of all colours is cleaned to <1% non-glass to eliminate contaminants that may alter the consistency of the finished product. The cleaned glass is milled into a superfine powder, which is then measured and mixed with a foaming agent prior to being kiln-fired.
Once the glass powder mixture is prepared, it’s deposited onto a chain link belt, which moves slowly through the kiln at a specific thermal profile to slowly heat the glass. The glass softens as it heats up, causing a chemical reaction that results in the mixture foaming up and creating a network of closed cell micropores.
After exiting the kiln, the mixture emerges as a thick foam glass slab. The slab quickly begins breaking and cracking due to thermal stress from the exposure to ambient temperature air. Over the next few minutes of cooling, the aggregate pieces continue to fracture until the particle sizes are 2-3 inches in diameter. At the far end of the cooling table, pieces are discharged onto a conveyor system, where they’re sent to bagging or storage.