{"id":148539,"date":"2024-07-24T07:35:00","date_gmt":"2024-07-24T05:35:00","guid":{"rendered":"https:\/\/renewable-carbon.eu\/news\/?p=148539"},"modified":"2024-07-19T11:23:13","modified_gmt":"2024-07-19T09:23:13","slug":"recycling-cement-paste-a-cheap-and-efficient-way-to-curb-emissions","status":"publish","type":"post","link":"https:\/\/renewable-carbon.eu\/news\/recycling-cement-paste-a-cheap-and-efficient-way-to-curb-emissions\/","title":{"rendered":"Recycling cement paste \u2013 a cheap and efficient way to curb emissions"},"content":{"rendered":"\n\n\n

Recycling cement paste is one of the cheapest and most efficient ways to reduce emissions from cement production, a new study published recently in PNAS<\/em><\/a> has found. The research, led by experts at Imperial College London\u2019s Department of Civil and Environmental Engineering<\/a> and including scientists from Empa and EPFL, highlights that waste cement paste that has undergone CO2<\/sub>\u00a0mineralization is a cost effective way to reduce emissions from cement.<\/strong><\/p>\n\n\n

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Demolition waste concrete: A new study highlights, that waste cement paste that has undergone CO2<\/sub>\u00a0mineralization is a cost effective way to reduce emissions from cement. \u00a9 Unsplash<\/figcaption><\/figure><\/div>\n\n\n

It found that CO2<\/sub> mineralization \u2013 a process where emitted and atmospheric CO2<\/sub> is reduced by absorbing it in infrastructure like concrete, bricks, pavers, and clinker substitutes \u2013 has the potential to reduce emissions from cement production by 15%, which is the equivalent of 0.8% of global greenhouse gas emissions in 2020.<\/p>\n\n\n\n

Of the 10 technologies studied that use CO2<\/sub> mineralization, the researchers found that recycled cement paste made from demolished concrete was most effective and economical. Cement paste is a glue-like substance that binds materials like sand or gravel together to create concrete. Recycled cement paste typically originates from old infrastructure, like demolished office buildings.<\/p>\n\n\n\n

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Lead author Rupert J. Myers, from Imperial<\/strong>\u2019s Department of Civil and Environmental Engineering, says: \u201cIn the fight against climate change, reducing emissions from the production of cement, and the construction industry more widely, is challenging. Our findings suggest that CO2<\/sub>\u00a0mineralized cement paste could be a champion technology in helping us decarbonize the sector.\u201d<\/p>\n<\/blockquote>\n\n\n\n

Examining company claims<\/h3>\n\n\n\n

Construction materials are responsible for around 13% of global greenhouse gas emissions \u2013 most of which come from manufacturing concrete and steel. Concrete is the second most in-demand material on the planet after water, and this demand is only expected to grow. For these reasons, scientists have been seeking solutions to reduce emissions from concrete and cement production and use.<\/p>\n\n\n\n

To carry out the study, the researchers looked at 10 different technologies that claim to effectively mineralize CO2<\/sub> in cement. They found that only two of the technologies were effective and economical in reducing CO2<\/sub> emissions from the cement production process.<\/p>\n\n\n\n

For most technologies, there was poor or limited evidence that they can reduce CO2<\/sub> emissions in real-life situations, despite companies claiming that they are effective.<\/p>\n\n\n\n

They also found that economical CO2<\/sub> mineralization-based technologies were between two and five times less expensive than Carbon Capture and Storage (CCS) technologies, where carbon is captured and stored underground.<\/p>\n\n\n\n

An added benefit of CO2<\/sub> mineralization is that it is a permanent solution that is relatively simple to manage. Construction materials can store CO2<\/sub> for hundreds of years in infrastructure, and possibly longer when demolished materials are recycled.<\/p>\n\n\n\n

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Co-author Justin D. Driver<\/strong> from the Department of Chemical Engineering says: \u201cAlthough these findings are promising, it\u2019s important to realize that CO2<\/sub>\u00a0mineralization is not a silver bullet solution. There is a limitation on the amount of raw materials available that can absorb CO2<\/sub>, meaning the potential for the technology to reduce emissions across all sectors is also limited.\u201d<\/p>\n\n\n\n

And Ellina Bernard, co-author and scientist at Empa<\/strong>‘s Concrete and Asphalt lab, adds: “This study shows that the bottleneck for a wider application of CO2<\/sub>\u00a0mineralization of end-of-life concrete or other calcium-based industrial waste is the limited supply of carbonatable material. However, CO2<\/sub>\u00a0savings of 15% in the production of useful building products are not negligible, and research should continue to focus on reducing the costs and further advancing these Carbon Capture and Utilization (CCU) technologies.” CCU is also at the heart of Empa’s new research initiative, Mining the Atmosphere.<\/p>\n<\/blockquote>\n\n\n\n

Reducing the carbon footprint of cement<\/h3>\n\n\n\n

The research team, which also includes researchers from Empa (Swiss Federal Laboratories for Materials Science and Technology) and EPFL (Swiss Federal Institute of Technology Lausanne), highlight some important focus areas for policymakers, investors, researchers, and other stakeholders as they seek to reduce emissions from the cement sector:<\/p>\n\n\n\n