Decarbonizing concrete: a pressing issue

Good news: innovations that aim to reduce concrete's GHG emissions are multiplying.

Decarbonizing concrete: a pressing issue

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.

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).

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.

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).

At sustamize, we look forward to integrating these new material and production process alternatives into our extensive #CO2 database to further provide our customers with accurate #carbonfootprints.

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