Old glass may find use in new, better concrete
Although glass is thought of as being relatively eco-friendly because it's recyclable, the fact is that a lot of it doesn't get recycled – this is particularly true of small fragments, that are too fiddly to sort. Now, however, scientists are suggesting that glass waste could be used to make concrete that's stronger and cheaper than ever.
Led by Dr. Riyadh Al-Ameri, researchers at Australia's Deakin University started with various pieces of non-recyclable glass, then ground them up into a coarse powder. They then utilized that powder as an aggregate in polymer concrete, in place of the sand that's normally used. Polymer concrete itself substitutes polymer resin for cement as a binding agent, and is typically used in applications such as waterproof flooring.
When the glass-based polymer concrete was subsequently tested, it was found to be significantly stronger than its traditional sand-based counterpart.
Additionally, because sand has to be mined, washed and graded, it was determined that use of the ground glass resulted in lower concrete production costs. What's more, while a shortage of appropriate sand has been predicted, there are currently stockpiles of old glass that are just sitting around unprocessed.
"This research provides the evidence the construction industry needs to see the potential of glass as a substitute for sand when making polymer concrete and, potentially concrete," says Al-Ameri. "Worldwide, the construction industry represents six per cent of global GDP, according to the World Economic Forum. Concrete is a major construction material and sand is one of its primary components, so finding an alternative to sand makes good economic sense."
In fact, Deakin isn't the first Australian university to explore the use of recycled glass in concrete. Earlier this year, scientists at the University of Queensland announced a method of rendering glass waste into liquid silicate, which could then be utilized in applications including a concrete sealant.
Source: Deakin University