LC3 - Low-Carbon Alternative to Cement Being Developed by Three Leading IITs and TARA

IIT Delhi, IIT Madras, IIT Bombay and TARA have made significant progress in the development of a new cement blend that promises to reduce CO₂ emissions by up to 30%. Applied globally, it could help bring down future global CO₂ emissions by several notches. Over a hundred and fifty tonnes of the Limestone Calcined Clay Cement have already been produced and used in three buildings including a building of the Swiss Embassy in Delhi. In this regard, a stakeholders meet was organised recently at IIT Bombay.

Advantages of the new blend:

·         Up to 30% lower carbon-dioxide emissions: because only half the amount of Portland cement clinker is used

·         Lower cost: owing to abundantly available substitution materials

·         Lower capital: Existing equipment can be used, with small additional investment (

·         Energy efficient: lesser energy required for manufacture

·         Waste utilization: can use existing mining, overburden and other kaolinitic wastes

·         Conservation: extends the life of limestone reserves

·         High performance: Meets the needs of both industry and users and gives high performance on many benchmarks

·         Responds to the growing global demands for cement in emerging economies

·         Requires no additional training of construction workers

LC3 was developed in close collaboration with industrial partners and designed to integrate into existing cement production lines. Clay and limestone are available en masse in quarries around the world. And consumers will be able to use it the same way they use ordinary Portland cement today. The strength of the combination of calcined clay and ground limestone, which the researchers call LC3 for Limestone CalcinedClay Cement, lies in its chemistry. When used together, the aluminates from the calcined clay interact with the calcium carbonates from the limestone, leading to a less porous, and therefore stronger, cement paste. While in the past, these materials have been used individually to replace a small fraction of the cement, together, they can replace up to half without altering the performance of the final product.

Funded by the Swiss Agency for Development and Cooperation (SDC) the project is led by the Ecole Polytechnique Federale de Lausanne (EPFL) in Switzerland, which has partnered with three IITs along with Universidad Central de Las Villas, a university in Cuba. In India, the research groups involved are from IIT Delhi (IITD), IIT Bombay (IITB) and IIT Madras (IITM).  The application of the technology is led by Technology & Action for Rural Advancement (TARA), in association with cement companies advised by Dr.A.K.Chatterjee, ex. Director ACC.

The overall lead for the Indian team are Dr. Shashank Bishnoi of IITD and Dr. Soumen Maity of Tara. The other researchers involved are Prof Biswajit Bhattacharjee from IITD, Dr. Prakash Nanthagopalan from IITB, Prof. Manu Santhanam, Prof. Ravindra Gettu, Dr. Radhakrishna Pillai and Dr. Sivakumar Palaniappan from IITM, and Dr. Arun Kumar, Dr. Soumen Maity and Palas Kr. Haldar from TARA. The results from all partners have demonstrated the feasibility of the cement with field applications and laboratory tests and now the team is involved in further understanding the science that would help in the optimisation of the cement.

Commenting on the collaboration between the IITs, Prof. Manu Santhanam, IITM said “This is one of the few times that three leading IITs have joined hands to work on a project of this magnitude with a lot of challenges and industry interaction. The project is thus expected to open up new possibilities in high quality research collaboration between IITs, in addition to providing new avenues for industry – academia interaction.” The global significance of the project is explained by Dr. Soumen Maity, TARA, “The project showcases the application of science and technology to meet the sustainable developmental needs across the World. Through this research and technology development initiative India is poised to lead the transfer of cutting-edge technologies across the world, thereby becoming the global leader of knowledge application.”

Edge over traditional raw materials

Industrial waste products that are commonly used today – slag from the steel industry or fly ash from coal power plants are two examples – but are not available in large enough quantities at all locations to keep up with demand. Further, fly ash usage as a supplementary cementing material is restricted by its relatively low dosage and also the high variability in quality.

Cement demand in India

The cement production in India doubles every 8 to 12 years and this capacity expansion comes at a huge capital investment. LC3 provides an opportunity for producers to increase the capacity of their existing plants at a fraction of the incremental capital investment. The growth of the cement industry and therefore the infrastructure in India is often projected without considering a possible exhaustion of the natural resources necessary for this growth. For example, cement producers are already importing coal and the industry is already concerned about the quantity and quality of limestone reserves. By utilising low quality raw materials and by reducing processing energy, this cement will support the growth of the India. The trials in India demonstrate that this cement can be produced using technology that is widely available in the country and that the cement can be used by construction workers without any additional training required to handle the material.

Dr. Shashank Bishnoi, IITD explains “The market cost of cement (approximately Rs. 6 per kilogram) is less than a third of the same weight of bottled water. This makes cement appear to be a cheap and boring material not worth studying. But the fact that today we produce around 300 million tonnes of cement every year to support the growth of our nation and that this contributes to 7% of all our CO₂emissions highlights the importance of development in the area.”