Recycling is important. If we could reuse our waste and create something really useful, we would solve several problems with one move. Now scientists at the University of Sydney have developed carbon dioxide-loaded cement, which is made using industrial by-products and could be used in a variety of construction applications.
Cement is everywhere in construction. It’s tough and relatively cheap. Pretty much all modern buildings have concrete in them, which uses a lot of energy and resources to produce. For example, tonnes and tonnes of sand are used in construction every day to a point where scientists are wondering if we are going to have a sand shortage in the near future. Scientists in Australia now poured a pavement using their “green” cement, which is made from a unique mixture of ash, ground glass and gaseous carbon dioxide.
In this case (and the pour was relatively small) eco-pavement saved 752 kg of sand, which would have to be dredged out using heavy machinery. 327 kg of CO2 emissions were avoided. And, unlike traditional concrete, this new material was not that energy intensive to produce – eco-pavement saved the equivalent energy of 1,000 cups of coffee or driving a car over 1,800 km.
Professor Ali Abbas, one of the researchers in the project, said: “We sought to create a less energy intensive solution that would have less impact on the environment using carbon-capture and beneficially reusing materials that would otherwise end up in landfill.”
It is interesting to see that the recipe for this “green” cement is actually pretty simple. Ash comes as a by-product or coal combustion. Waste glass can be recycled in a variety of ways, but this time it was just ground up. Scientists say that less than half of the 1.4 million tonnes of glass produced each year in Australia is recycled. Essentially, ash replaces cement and glass replaces sand and aggregates.
And CO2 is just locked inside of the concrete in a mineral form. This prevents this greenhouse gas from entering the atmosphere. Obviously, we are not lacking CO2, but it would be cool if scientists managed to use CO2 that is captured directly from the atmosphere by specialized equipment. This would kill several birds in one stone – create eco-friendly concrete, reduce waste and clean up the atmosphere a bit.
Now that the eco-pavement is done, scientists will begin a 12 month period of continuous monitoring. They want to see whether it performs as expected and can withstand everything a traditional concrete can. Scientists hope to later commercialise the technology and introduce it to the market as an alternative to traditional concrete.
Source: University of Sydney