Glass is one of the most versatile materials on Earth. Desktop screens, a glass to hold water, smartphone and watch screens, the artwork's frame on the wall, and even glasses are some examples of forms that glass takes for our use. 

After use, glass is often condemned to a life in piles of waste or it's recycled. More specifically, glass can be recycled as it is classified as a pozzolan; and used to replace Portland cement in concrete mixtures. 

As illustrated on our website, pozzolans include a broad category of materials, both naturally occurring and by-products of various modern manufacturing processes but can be generally defined as being mainly siliceous or silico-aluminous material that will, in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to form compounds having cementitious properties.

Processed into a fine powder, ground glass can replace up to 40% of Portland cement in a mix, creating a stronger, denser, less permeable, and more durable concrete while making use of a readily available, inert waste material. Pozzolans such as ground glass can also improve concrete’s workability and reduce the amount of water and chemical admixtures required.

Recently, an article by The Conversation highlighted this fact, whilst investigating the probability of using the glass, concrete mix in 3D printing the houses of the future... Talk about the race to a Net-Zero future! 

"Our research shows that an ultra-lightweight, well-insulated 3D building is possible – something that could be a vital step on our mission towards Net-Zero."

In the US, roughly only a quarter of glass is recycled, with more than half going into landfill. A team of scientists banded together to find a solution to this pressing issue in light of the global race to Net-Zero. 

These scientists used brown soda-lime beverage glass (obtained from a local recycling company) and utilised the glass much like sand usually is when making traditional concrete. They found it worked 'remarkably well' allowing the concrete to develop superior properties when compared to conventional mixtures. When this was highlighted, the mixture became a candidate for the 3D printing of houses. 

To make the mixture even more sustainable, even the Portland cement was partially replaced- using limestone powder. Naturally, doing so meant a hopeful reduction in the C02 emissions that Portland cement contributes to. Lightweight, thermoplastic fillers were added in conjunction with the limestone, which altogether changed the conductivity of the concrete and reduced it by 40%! 

Implementing these changes allows for less virgin material to be used and helps our environment by recycling other repurposable materials. It also highlights the notion that mixtures such as this can be used to develop possible eco-friendly houses in the future as a construction alternative. 

What do you think? Would you live in a 3D printed house made of recycled glass? Let us know on LinkedIn or Twitter!