🧱 What is sustainable concrete?

Carbon capture and storage. Recycled plastics mix. Meta AI research.

This week I met a very interesting person, an Architect with a sustainability vision and technology minded. We spent the warm summer evening talking about inspiration from nature, why some buildings are not as green as it claims, and sustainable material innovations.

It makes me question how we can make concrete, the most important material in construction, to be more sustainable. Let’s dive deep!.

Is concrete bad?

Concrete is a mixture of gravel, sand, water, and cement. Used to create the foundations and building blocks of most modern houses and structures. It has a long history, with earlier versions dating back to the Mayan and Roman civilizations. 

Thanks to concrete, we can build strong houses to protect us from earthquakes or fire. For example, during the Hiroshima atomic bombing in WWII, 90% of the buildings in the city were burnt down, and most are made of wooden houses. Only several buildings that were made out of concrete survived until today. 

With the rapid development around the world, no wonder that concrete is the world's second most used material, behind water. 

However, the production of cement that is used to make concrete is one of the biggest contributors to global carbon emissions. The cement industry contributes to around 8% of the world's greenhouse gas emissions (2.8 billion tonnes of CO2), more than the annual emission of India.

Not because of the energy consumption during production, but due to the chemical that was released during the process. Cement is made by burning limestone to produce calcium, which unfortunately also produces an equal amount of carbon dioxide as a byproduct. 

Bill Gates, in his book “How to avoid a climate disaster” has warned that we need to find a more sustainable solution to produce cement. 

So what is sustainable concrete?

🏭 Carbon capture: 

Carbon capture storage is the technology to capture the carbon dioxide (CO2) before it's released to the atmosphere and store it in a safe form. One of the methods is to capture and convert CO2 into minerals and mix it to the cement. 

This is called closing the loop, what goes out goes back in. The result is a low carbon concrete with the same or even stronger quality than the conventional one. 

Various cement manufacturers have started to implement carbon capture storage technology in their plants. For example Carbon cure, a solution provider in this field, has deployed its technology in more than 400 plants globally.

♻️ Recycled plastic mix:

With the boom of constructions in the 21st century, there is a huge demand for sand to make concrete. Growing up in Indonesia, I still remember reading news of illegal sand mining around the Riau archipelago, to be exported to Singapore, which is only 50km away. 

A recent project in India discovered that recycled plastics can be mixed with sands to create concrete. Pellets of recycled plastics are mixed in concrete slabs to use for pavement and building. This is a perfect solution for countries like India who are facing both shortage of sand and excess of wastes. 

🖥️ Meta AI research:

Meta, Facebook’s parent company, seems not only interested in the digital world, but also in the construction of the physical world. Recently, its Artificial Intelligence (AI) team has worked with researchers from the University of Illinois in using AI to find the best materials to make concrete with the most efficient carbon emission output. 

As a result, it claimed to have found a recipe to lower down carbon emission in concrete production by 40%. Thanks to AI technology, the team can model more than 1000 types of mixtures, which are not easily done in a traditional experiment setting.

Conclusion

Concrete plays an important part in our life. To build our houses, schools, offices, and other buildings that we spent most of our time in. 

To close this article, I would like to quote from a classic song that many of us are familiar with: 

“They paved paradise, and put up a parking lot” Joni Mitchell

Unless we find a new innovation to replace concrete, we need to use more sustainable concrete and keep earth as our paradise for the next million years.

Thanks for reading this article and enjoy the weather ☀️.