Researchers at the Indian Institute of Science's Centre for Sustainable Technologies (CST) in Bengaluru, Karnataka, have developed an innovative material capable of replacing natural sand in construction.
Souradeep Gupta, an Assistant Professor at CST, and his team have discovered that using carbon dioxide (CO2)-treated construction waste instead of natural sand in mortar and curing it in a CO2-rich environment can accelerate the improvement of its engineering properties and enhance its compressive strength by 20-22%.
Scientists are exploring ways to store carbon dioxide from industrial gas in dug-up soil and construction debris, which could then serve as a partial replacement for natural sand.
"The amount of construction and demolition (C&D) waste is on the rise – about 150 million tonnes are generated annually in India and the recycling rate is only about 1%... This [process] would not only reduce the environmental impact of construction materials but also impart properties that can enhance their use for construction," experts said in the statement.
Gupta explained that the utilization and sequestration of carbon dioxide can be a scalable and feasible technologies for manufacturing low-carbon prefabricated building products, aligning with the nation's decarbonization targets.
His team conducted experiments to assess the impact of carbon dioxide gas injections into clayey soil.
These tests revealed significant improvements in the soil's stabilization when combined with cement and lime. This process not only decreased the surface area and pore volume of the clay but also reduced its reactivity to lime, ultimately enhancing the overall engineering qualities of the material.
Researchers at the Indian Institute of Science's Centre for Sustainable Technologies (CST) developed an innovative material capable of replacing natural sand in construction.
© Photo : Indian Institute of Science
When scientists sequestered carbon dioxide in excavated soil to create cement-lime-soil materials, they boosted their early-age strength by about 30%.
Gupta explains that exposure to carbon dioxide after preparation also reduces the curing time required for them to harden before being used in construction.
The team has also developed 3D-printable materials made of excavated soil stabilised with a combination of binders like Portland cement, blast furnace slag (a granular calcium-silicate byproduct), and fly ash.
They discovered that utilizing these materials could reduce the required amounts of cement and natural sand in mortar by 30% and 50%, respectively.
Researchers at the Indian Institute of Science's Centre for Sustainable Technologies (CST) developed an innovative material capable of replacing natural sand in construction.
© Photo : Indian Institute of Science