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Concrete is quickly becoming a great carbon sink with high-tech advances

Concrete forms the backbone of human civilization’s most impressive structures. Ancient Romans built aqueducts with it. We use it for modern highways.

This versatile material builds our cities, roads, and bridges. It enables societal progress and urban development. Concrete is the second most consumed material globally, after water.

But concrete production has a big downside. It significantly contributes to greenhouse gas emissions. The cement industry accounts for about 8% of world CO2 emissions. This fact highlights the need for innovative solutions.

Teaching concrete to capture CO2

The good news? A Northwestern University-led team of engineers has discovered an innovative method of carbon sequestration that could revolutionize the concrete industry and potentially curb these CO2 emissions.

This breakthrough could mark a turning point in our efforts to mitigate the environmental impact of concrete production.

The process, led by Alessandro Rotta Loria from Northwestern’s McCormick School of Engineering, is surprisingly simple: use carbonated water in concrete manufacturing instead of still water.

Not only does the end product possess uncompromised strength and durability, but it also efficiently stores carbon dioxide. The team found that almost half of the CO2 introduced during the manufacturing process was captured and stored.

From carbon source to carbon sink

This is a significant leap in the field of carbon sequestration in concrete production that could change the industry’s future and pave the way for more sustainable construction practices.

Rotta Loria, the Louis Berger Assistant Professor of Civil and Environmental Engineering, is working on innovative solutions.

He explains, “We are trying to develop approaches that lower CO2 emissions.” His team aims to transform cement and concrete industries. They want to turn these sectors into large carbon sinks.

Loria’s team has made progress. They’ve found a way to reuse CO2 from concrete manufacturing in the material itself. He notes, “Our solution is so simple technologically that it should be relatively easy for the industry to implement.”

CEMEX to the rescue

Many industry experts share Loria’s optimism. They believe this method could be widely adopted. It offers a practical way to reduce the carbon footprint of concrete production.

The fascinating research was a result of a partnership between Rotta Loria’s laboratory and CEMEX, a global building materials company dedicated to sustainable construction.

On this new method, Davide Zampini, vice president of global research and development at CEMEX and co-author of the study, noted that the approach provides an opportunity to engineer new clinker-based products where CO2 becomes a key ingredient.

This collaboration demonstrates the power of industry-academic partnerships in driving forward sustainable innovations.

Refreshing approach to carbon sequestration

The team at Northwestern didn’t merely decide to put some fizz in their concrete. They meticulously built upon previous research that explored various ways to store CO2 inside concrete.

Their approach involves injecting CO2 gas into water mixed with a little cement powder before mixing this carbonated suspension with the rest of the cement and aggregates.

This method ensures that the CO2 is efficiently integrated into the concrete mix, maximizing the amount of gas sequestered.

The result? A game-changing concrete that actually absorbs CO2 during its manufacturing process. Rotta Loria compared it to current methods.

Concrete, carbonation, and CO2

“The cement suspension carbonated in our approach is a much lower viscosity fluid compared to the mix of water, cement, and aggregates that is customarily employed in present approaches to carbonate fresh concrete,” Loria explained.

This lower viscosity makes the new method easier to work with and potentially more effective in sequestering CO2.

On the strength of this carbonated concrete, the researchers found it to be no weaker than regular concrete.

“Based on our experiments, we show the strength might actually be even higher. We still need to test this further, but, at the very least, we can say that it’s uncompromised,” Loria enthused.

“Because the strength is unchanged, the applications also don’t change. It could be used in beams, slabs, columns, foundations — everything we currently use concrete for.”

This ensures that the new method can be easily adopted without requiring significant changes to existing construction practices.

Paving the way to a sustainable future

The Northwestern team’s innovative solution brings hope to an industry grappling to reduce its carbon emissions. If widely adopted, this could be a game-changer in the battle against climate change.

According to Davide Zampini, it underscores the fact that there’s always room for optimizing CO2 uptake and understanding the mechanisms tied to materials processing.

This research serves as a reminder that sustainable solutions are within our reach, and with continued research and collaboration, we can significantly reduce the environmental impact of critical industries.

In a world urgently seeking solutions to environmental issues, this revolutionary approach to concrete production leveraging carbonation could have a profound impact. It offers a sustainable pathway for the industry, increasing the material’s strength while decreasing its carbon footprint.

The potential is immense, and we look forward to the transformation this will bring to industrial practices and the future of sustainable construction.

The implications of this research extend far beyond the concrete industry, serving as a beacon of hope for other sectors seeking to reduce their carbon emissions and achieve greater sustainability.

The full study was published in the journal Communications Materials.


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