Decarbonizing concrete: a pressing issue

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Green Cement: Can It Reduce the Carbon Footprint of Concrete?

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Did you know that concrete accounts for at least 8% of man-made global emissions, which is more than double the emissions of airplanes or ships, according to Deutsche Welle (2022)?

The popular, long-lasting building material has been used for centuries and is now essential around the world, with data showing that three tons of concrete are used per year for every person in the world (Gagg, 2014). With the climate crisis and the drive for decarbonization, it is critical that material innovations be used to reduce the associated greenhouse gases.

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Why Cement Is Responsible for Most Concrete Emissions

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A 2021 Nature magazine editorial explains why concrete is so harmful to the environment:

"Concrete is made by adding sand and gravel to cement, whisking the mixture with water and pouring it into moulds before it dries. Making the cement is the most carbon-intensive part: it involves using fossil  fuels to heat a mixture of limestone and clay to more than 1,400  °C in a kiln. Also, when limestone (calcium carbonate) is heated with clays, roughly 600 kilograms of carbon dioxide is released for every tonne of cement produced (see the very insightful article by Nature: go.nature.com/3exhg82)." (Nature, 2021).

In other words, decarbonizing the concrete industry begins with trying to make cement greener. There are several innovations underway aimed at developing a "green cement." Researchers at the University of Sydney, for example, have focused their efforts on circular economy principles and are working on a type of "green" cement that is a blend of fly ash and waste materials such as ground glass and gaseous carbon dioxide (University of Sydney, 2020).

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How Green Cement Can Reduce CO₂ Emissions

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Other researchers are more focused on innovating the process of cement production, such as Dr. Peter Stemmermann, who is one of the inventors of "celitement." According to the researcher at the Karlsruhe Institute of Technology, celitement has much more favorable material and energy balances, unlike conventional cement. Its production is less costly and saves energy because it takes place at significantly lower temperatures. It also allegedly conserves resources because it requires less lime. Finally, it releases up to 50 percent less CO2 than conventional cement.

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What Other Technologies Could Decarbonize Concrete?

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There are other innovations in the works around the world that have the potential to dramatically reduce CO2 emissions from concrete. For example, this could be done through a combination of carbon capture and storage (CCS) technologies as well as fuel and intermediate product substitutes (Brogan, 2021).

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Why Carbon Footprint Data Is Essential for Green Building Materials

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Developing innovative materials is only the first step. Their climate benefits must also be measured consistently.

Reliable Product Carbon Footprints (PCFs) enable manufacturers to compare new cement formulations with conventional alternatives, quantify emission reductions, and support sustainable procurement decisions.

Transparent, science-based CO₂ data is therefore essential for identifying which innovations deliver genuine climate benefits.

The Future of Low-Carbon Concrete

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Green cement has the potential to become one of the most important innovations for decarbonizing the construction industry.

At sustamize, we continuously monitor new materials and manufacturing technologies and look forward to integrating validated carbon data for these innovations into our Product Footprint Engine, helping companies compare materials and make better-informed decisions for low-carbon construction.

Sources

Brogan, C. (2021, May 20). Best ways to cut carbon emissions from the cement industry explored. Imperial News. Imperial College London. https://www.imperial.ac.uk/news/221654/best-ways-carbon-emissions-from-cement/

Erneuerbare Energien (2021, July 16). Grüner Zement durch grünen Wasserstoff? Erneuerbare Energien. https://www.erneuerbareenergien.de/betrieb/gruener-zement-durch-gruenen-wasserstoff

Gagg, C. R. (2014). Cement and concrete as an engineering material: An historic appraisal and case study analysis. Engineering Failure Analysis, 40, 114–140. https://doi.org/10.1016/j.engfailanal.2014.02.004

Karlsruhe Institute of Technology (n.d.). Celitement - Dr. Peter Stemmermann. Bindendes Versprechen an die Umwelt. https://www.sek.kit.edu/un-klimakonferenz2015_stemmermann.php

Low, L. (2020, October 1). "Green" cement pour yields concrete results. News. The University of Sydney.

https://www.sydney.edu.au/news-opinion/news/2020/10/01/-green--cement-pour-yields-concrete-results.html

Mrasek, V. (2015, January 1). Clean and Green: Grüner Zement. Deutschlandfunk. https://www.deutschlandfunk.de/baustoffe-gruener-zement-100.html

Nature editorial (2021). Concrete needs to lose its colossal carbon footprint. Nature, 597(7878), 593–594. https://doi.org/10.1038/d41586-021-02612-5

Niranjan, A. (2022, February 4). Green construction: Fixing concrete's carbon footprint. Deutsche Welle. https://www.dw.com/en/concrete-cement-climate-carbon-footprint/a-60588204

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