We have talked alot about recycling and how materials can be recycled into a new life. I remember reading an article at the beginning of the semester about recycling glass in concrete and almost where the concrete seemed translucent due to the glass. I wondered though, if that is really sustainable and even structurally sound now after talking about recycling and using products and materials in a sufficient way. I mean, we all love to recycle and save our planet, but are we being smart about it all the time when it comes to it or do we just recycle whatever we can in whatever we can just to do so? I looked up recycled glass reinforced concrete to get a little better understanding of the material and process.
Aggregate makes up 70-80% of the concrete volume and provides hardness, strength, and durability. Depending on the specific aggregate used will define those three characteristics. There are numerous alternatives to using aggregate such as granulated coal ash or granulated plastics, but glass has always been an option as well. However, when it comes to the type of glass used in the concrete, it must be paid very special attention to. Recycled glass is not the only type used. Glass that is “unsuitable” for recycling and “non-recyclable” glass are also used such as fragments of flourescent bulbs and glass bottles. Sometimes the “non-recyclable” glass has smal contaminants within it. This is where we must pay attention to the details.
Even though it may seem that all kinds of glass can be used in concrete for recycling, they cannot. Glass with small contaminants can affect the concrete overall after time weakening the concrete strength and decrease its long-term durability. What occurs to create such questionability is a alkali silica reaction between the cement paste and the glass aggregate which produces weakness in the concrete. So if you ever wondered why glass concrete was only seen in countertops and floors and not walls, this is why! Research is still taking place in order to improve such a process, innovation is still in process.