A Sustainability Impact Assessment of Limestone Calcined Clay Cement (LC3) in a project supported by the Swiss Agency for Development and Cooperation shows a reduction of nearly 40% CO2 emissions and 20% lower energy for production when compared to ordinary Portland cement.
Simultaneously, research conducted 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, with support from the Swiss Agency for Development and Cooperation, India, has shown that the concrete produced with this cement has excellent strength and durability characteristics.
Low Emissions
Technologists have generally agreed that one of the primary ways to reduce the net carbon impact of concrete construction would be to use less cement clinker in
concrete, to make better use of by-product materials from mining, agriculture, and industry, and to reduce waste through better construction techniques.
Limestone Calcined Clay Cement (LC3) is a cement that combines Portland cement clinker, calcined kaolinitic clay, and limestone with gypsum. Because the production of clinker involves the burning of limestone, the extent of cement clinker is limited to only 50%, implying a significant reduction in CO2 emissions.
The clay used in LC3 is usually a non-ceramic grade raw material extracted from China clay mines including the overburden, while the limestone used in the blend can be from low-grade sources that are not suitable for cement manufacture.
Sustainability impact assessment has clearly demonstrated a reduction of nearly 40 per cent of CO2 emissions, and about 20 per cent lower energy for the production of LC3 as compared to ordinary Portland cement.
About LC3 cement
LC3 is a general-purpose cement, and its production does not require the establishment of a green field unit. It is simple to integrate into an existing production system. It is also around 25% cheaper to produce due to lower energy requirements, depending on clay availability. LC3 is poised to improve the sustainability of concrete construction by having a clear impact on the environment, society, and economy.
Speaking about the results of the recently concluded long-term research on LC3, Manu Santhanam, Dean (Industrial Consultancy and Sponsored Research), IIT Madras, said, “Inter-university research spanning across several years and conducted at different scales clearly indicate the superior performance of this cement in coastal areas, which, combined with the major impact on CO2 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.”
Elaborating on the need for sustainable construction materials like LC3, Dr. Soumen Maity of TARA New Delhi said, “With the shift of government priority to renewable energy, the availability of fly ash is going to be constrained. The LC3 or Limestone Calcined Clay Cement provides a profitable and technically viable option of reducing the carbon emissions in existing cement production. It can easily be integrated into the existing production system thus reducing the need for high CAPEX. TARA, along with academic Institutions are supporting cement companies to initiate the change to more sustainable cement production.”
Highlighting the importance of collaborative research and its impact, Shashank Bishnoi of IIT Delhi, said, “LC3 is a perfect example of how international collaboration can rapidly bring sustainable technologies from the laboratory to the market. The synergy created by the varied expertise of the team members allowed a much deeper understanding of LC3 than many of the cement that we already use.”
