Concrete & Construction: An Unbreakable Bond?

June 2, 2021

Concrete is the 2nd most consumed substance in the world, behind water, and 70% of the world’s population lives in a structure that contains concrete. But why is this? What makes it so useful and significantly what are the impacts of its astronomical consumption? Concrete’s immense popularity can be attributed to its durability, strength, versatility and availability.

For these reasons, it has been used as a building material for thousands of years, with notable ancient buildings including the Pantheon and Colosseum in Rome. So, it’s easy to make and incredibly useful, but what are the downsides? One of the key ingredients, cement is the source of about 8% of the world’s CO2 emissions, and if the cement industry were a country, it would be the third-largest emitter in the world.

So, what can we do to try and change this? Can we ever replace concrete with an environmentally friendly alternative, or should our efforts be placed on trying to make it as ‘green’ as possible? An alternative material that is gaining traction is cross-laminated timber (CLT). It’s produced by gluing strips of laminated wood together at 90° angles, before being compressed into beams or panels.

This material’s popularity is growing and was implemented recently in the construction of an 18-storey ‘plyscraper’ neighbouring the Mjøsa lake, in Norway. Environmentally, these buildings are far greener, with the wood they are made with locking in carbon emissions, rather than producing them as with concrete. These factors make a strong case for it’s use over concrete and we could start seeing a lot more of these types of buildings in the future.

What about making concrete greener? The components of concrete can be substituted for materials such as using blast furnace slag, and fly ash, instead of Portland cement. Experts say replacing up to 40% of cement content with these types of materials can be up to 30 times less greenhouse-gas emitting than traditional Portland cement.

Even without new materials, there are steps to make Portland-based concrete more sustainable. This can involve reusing the concrete from demolished buildings as the aggregate to prevent wastage. It remains to be seen whether we will be able to ever move away from concrete completely, but if the answer is no, we can undoubtedly take steps to improve its sustainability for the future.

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