Gallery: Ghent’s new urban furniture reduces CO2 emissions from concrete by 65%

Concrete is a major source of CO2 because of cement, however, mixes that exclude cement could be the future of one of the world's most used materials

Yesterday, local authorities in Ghent, Belgium, unveiled a renovated square that had street furniture made out of low-carbon concrete. This is a big step towards establishing a more sustainable circular construction sector, as concrete is a major CO2 emitter.

According to the Paris Climate Agreement, emissions from concrete need to be reduced by 16% in the next ten years, otherwise, nations risk missing their targets.

What is the problem with concrete?

Concrete is the most widely used man-made material in existence and while it has shaped much of our urban environment, cement - the key ingredient in concrete – has a massive carbon footprint. According to analysis from the think tank Chatham House it is the source of around 8% of global CO2 emissions.

If cement was a country, it would be the third-largest emitter after China and the US and it emits more than the entire aviation industry. At the same time, it is an extremely affordable, durable and versatile building material, which enabled the construction of amazing structures – from the Burj Khalifa to the Pantheon in Rome.

Sustainable concrete

The new benches in Ghent are made from a more sustainable mixture of raw materials, compared with traditional mixes. Most often, concrete is made from sand and gravel, as well as cement and water to help the materials bind together.

In this variant, however, cement is replaced with slag and ash, a by-product of the steel industry, while sand and gravel are replaced with by-products from mineral mining. The result - mixture’s carbon footprint is 65% lower than standard concrete.

The new process was developed as a part of the UBCON project in Ghent University, and, despite this initial success, the question of viability remains. Is the new mixture as durable and easy to produce in short amounts of time and can it be scaled up, without causing a shortage in raw materials?

These questions will be what determine the success of this particular low-carbon concrete and the project behind it, set to run between 2018 and 2023. The next development project for the group will be a concrete fire escape, mounted to the side of a Ghent school.

Sofie Bracke, Alderman of Economy, was quoted in a press release, saying: “Ghent is a European pioneer in the field of ‘cleantech’ and the reuse of raw materials. Collaborations with companies and educational institutions such as Ghent University are indispensable in this regard. We are experimenting a lot with this in our city.”