Indian Researchers Say CO2-Enriched Material May Replace Sand In Construction

Indian Researchers Say CO2-Enriched Material May Replace Sand In Construction - Carbon Herald

Researchers from the Centre for Sustainable Technologies (CST) at the Indian Institute of Science (IISc) are investigating methods to sequester carbon dioxide (CO2) from industrial flue gas in excavated soil found in construction and demolition (C&D) waste, according to a recent announcement by IISc.

This CO2-enriched material can then be utilized as a substitute for natural sand in construction applications.

Such an approach mitigates the environmental impact of construction materials while also enhancing their properties for building purposes, IISc said.

Assistant Professor Souradeep Gupta from CST emphasized the potential scalability and feasibility of this technology for producing low-carbon prefabricated building products, aligning with national decarbonization goals.

The construction industry faces a looming crisis as natural sand becomes increasingly scarce, with projections suggesting it could be depleted by 2050.

Not only is this a threat to the availability of a crucial resource, but it also exacerbates climate change due to the CO2 emissions associated with manufacturing cement and fired clay bricks.

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India generates approximately 150 million tons of C&D waste annually, with a meager 1% being recycled.

Research has demonstrated that incorporating treated C&D waste, enriched with CO2, into mortar can accelerate material development and improve compressive strength by 20-22% when cured in a controlled, CO2-rich environment.

In a more recent study, Gupta’s team explored the use of CO2 in excavated soil to develop cement-lime-soil materials, which are then used to replace up to 25% and 50% of fine aggregates by mass in mortar.

As explained by Ashutosh Dwivedi, a PhD student at CST and the study’s lead author, sequestering CO2 in cement-soil materials facilitates the formation of calcium carbonate crystals, leading to densification of interfacial zones and enhanced compressive strength.

Going forward, the team intends to investigate the impact of industrial and simulated flue gas, containing various gases like CO2, sulphur dioxide (SO2), and nitrogen oxide (NO), on the properties of their newly developed materials, aiming to understand how these gases affect carbon capture potential and engineering properties.

Additionally, they are discussing the application of their findings with prominent construction companies and collaborating on revising standards for natural and recycled aggregates in cement-based construction materials as part of a national committee led by Gupta.

Read more: India Announces Its Domestic Carbon Credit Trading Scheme (CCTS)

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