In a significant development, research undertaken by IIT-Madras with other National and International Agencies has shown that concrete produced with a new cement – Limestone Calcined Clay Cement (LC3)- exhibited strength and durable characteristics while carrying the potential to realise low carbon goals in the construction industry.
In a project supported by the Swiss Agency for Development and Cooperation, a Sustainability Impact Assessment of LC3 showed a reduction of nearly 40 percent in CO 2 emissions & 20 percent lower energy for production as compared to ordinary Portland cement.
At the same time, research was done by IIT Madras, IIT Delhi, TARA (Development Alternatives) New Delhi, UCLV (Central University “Marta Abreu” of Las Vilas) in Cuba, and EPFL (Swiss Federal Institute of Technology Lausanne) in Switzerland, supported by Swiss Agency for Development and Cooperation. India showed that the concrete produced with this cement exhibits excellent strength and durability characteristics.
Portland cement clinker production is responsible for nearly 8 percent of the global CO 2 emissions. Globally, there is a strong view that the primary means of reducing the net carbon impact of concrete construction would be lesser use of cement clinker in concrete, the judicious use of by-product materials from mining, agriculture, and industry, and minimise wastage through better construction techniques.
“Inter-university research spanning over several years and conducted at different scales indicate the superior performance of this cement in coastal areas, which, combined with the major impact on CO 2 and energy, can set the standard for producing sustainable concrete. Further, the work at IIT Madras has also resulted in a sustainability framework that can be used to assess the impact of such new cement in construction,” said Prof Manu Santhanam, Dean (Industrial Consultancy and Sponsored Research), IIT Madras.
LC3 is a blended, general-purpose cement incorporating Portland cement clinker, calcined kaolinitic clay, and limestone, in combination with gypsum. The extent of cement clinker is restricted to only 50 percent, implying a major reduction in CO 2 emissions since the production of clinker involves the burning of limestone.
Its production does not require setting up a green field unit, and it can easily be integrated into an existing production system. Due to lower energy requirements, it is also around 25 percent cheaper to produce, depending on the availability of clay.
“With the shift of Government priority to renewable energy, the availability of fly ash is going to be constrained. The LC3 provides a profitable and technically viable option for reducing carbon emissions in existing cement production. It can easily be integrated into the existing production system thus reducing the need for high Capex,” said Dr. Soumen Maity of TARA.
