Concrete. A universally durable and versatile construction material, concrete is the second most consumed substance in the world, right behind water.

As it stands, it’s hard to revise the widespread use of this material, which has been in use since its origins in Rome, 200 BC. The UN Population Division (2022) estimates that 56% of the human population now lives in urban cities. This intensifies the need for concrete for high density in infrastructure ranging from schools and office buildings to skyscraper living areas (Giatec Scientific, 2017).

Watts (2019): Concrete uses nearly a 10th of the world’s industrial water use, which is fresh water. Photograph: (2021) Excess-Water-in-Concrete.jpg. https://civilmint.com/effects-of-excess-water-in-concrete/.

Concrete’s heavy carbon footprint

Concrete cannot be a material relied upon as heavily as it is now. It is a nonrenewable resource that is mined, consumes lots of fresh water, requires large amounts of energy and actively releases emissions. All in all, concrete takes up an estimated 8% of the world’s global emissions (Ramsden, 2020).

All of us who live in cities are affected by this carbon footprint factor, as well as those who mine for the minerals required to build this grey material. If our future is to shift towards a circular economy, individuals who commission buildings and the construction and architectural industry must work together to apply different and greener alternatives to developing human habitats.

Evaluating Concrete for Sustainability

Concrete is a material that is very resource intensive. Its aggregates are made from mined materials, it needs to be heated at high temperatures and must be combined with copious amounts of fresh water.

It goes without saying that mines will never be good for the environment, because they cause lasting habitat destruction and large scale pollution and warming of nearby waterways.

Furthermore, it is not worthwhile to recycle concrete and it cannot be upcycled. Nevertheless, concrete production and trade is well established in Canada’s economy. Manitoulin, a mine for aggregates used in concrete, generates roughly $61 billion a year and employs hundreds of thousands of workers in Canada.

Is there a more Sustainable Alternative to Concrete?

There are working materials that are still in their pilot project stages that are gaining momentum in the construction industry. Here is the breakdown of the top four that are used around the world, all of which boast carbon-negative evaluations.

Wood

Wood, or its reinforced product, cross-laminated timber (CLT), is gaining momentum and use for large buildings and skyscrapers in the construction industry.

The Brock Commons student housing on the UBC campus in British Columbia is a wooden skyscraper completed in 2017. For fire-safety approval it was completed with some concrete, however, it is an example of how wooden structures are evolving in Canada.

Wood’s most redeeming quality as a construction material is that the timber is shaped to assemble beforehand which streamlines construction timelines. However, timber can only be partially recycled, but not upcycled, in its post-life stage.

Currently, the logging industry currently gives $12.6 billion back to Canada each year and employs tens of thousands citizens.

$ Price comparison:

Concrete: $2- $12/square foot

Cross laminated timber: $2- $6/square foot

Ferrock & Ashcrete

Ferrock is a building material made from waste steel dust. Ashcrete is a similar material alternatively made from fly ash waste from coal burning. Ferrock and ashcrete go hand in hand in repurposing common industry waste. However, as this durable product gains more and more popularity, this waste may go up in value.

Nevertheless, once completed, this material is many times stronger than concrete and has potential in buildings within marine environments.

Ferrock and ashcrete absorb CO2 from the atmosphere as it dries, making it an overall carbon-negative material.

Unfortunately, the product cannot be recycled and goes to the landfill, but it can last for many, many years.

$ Price comparison:

Unavailable

Mycelium

Mycelium is biomass derived from fungi, under trial to be a material in construction.

Dried and compressed mycelium presents durability comparable to that of concrete, and the leftover bricks at the end its use becomes biodegradable feed for new mycelium. This product embodies the ideals of the circular economy and will make many new jobs under its industry.

Photographs: Oscar-Vinck (2019). The-Growing-Pavilion. https://thegrowingpavilion.com/

Mycelium as a construction material has already been showcased in various architectural shows around the world, including The Growing Pavillion by Biobased creations and the Hi-Fi (pictured above), the Young Architect Program’s living mycelium tower (pictured below).

Photograph: (2014). Hy-Fi. https://www.holcimfoundation.org/Projects/hy-fi.

$ Price comparison:

Unavailable

Summary

Humans rely heavily on concrete in the construction of nearly all modern day buildings. This ties a large carbon footprint to all of us who live in cities and those of us who live among the urbanizing population.

However, research and trials are being done to bring greener alternatives to the design table which will provide a stable foundation in our stance against climate change.

Timber is a product that can be used in skyscrapers which is both renewable, carbon-sequestering and recyclable. Industrial waste can be converted into eternally durable ferrock and ashcrete, which may also lay the foundation for the future of marine buildings. Lastly, mycelium construction blocks will be a product that will complete the circular economy.

As the individuals or the organizations who commission buildings, whether by renovation or new development, we have the responsibility of overseeing who generates and controls the substances that go into our buildings. After all, we cannot have any more of Earth’s resources go to waste.