A new type of cement is currently being tested on a large scale in India. Known as LC3, this new blend substitutes up to half of the carbon intensive materials traditionally used to make cement in India

A consortium of researchers from Ecole Polytechnique Fédérale de Lausanne together with research and application partners from the Indian Institutes of Technologies of Delhi, Bombay and Madras as well as Technology and Action For Rural Advancement (TARA), New Delhi in partnership with universities in Cuba and Brazil have managed to double the quantity of cement produced from the same quantity of limestone by substituting a large portion of clinker (an intermediary material made by heating limestone at very high temperatures) with calcined clay. Limestone Calcined Clay Cement, or LC3, has the potential to generate 20-30% less CO2 emissions compared to traditional cement; a major reduction considering that cement accounts for 5-8% of today’s manmade emissions.

Materials such as slag and fly ash are already used worldwide to decrease the ratio of clinker needed to manufacture cement. However, these materials are not always available locally and their limited supply will not be able to meet the rapidly increasing demand for cement.

Global cement demand will double by 2050. By then, India will surpass China as the largest producer yet , India’s quarries are estimated to provide limestone for only 50-60 years more. LC3 can provide a long-term sustainable solution because it can use low grade kaolin clays, unsuitable for most industries and largely available in many parts of the word, including India”, explained Professor Karen Scrivener, LC3 project leader at Ecole Polytechnique Fédérale de Lausanne (EPFL).

LC3 is a low carbon and low cost cement that delivers similar or even superior performance properties compared to Portland cement. The blend can be easily manufactured in existing production lines, requiring only minor capital investments.

The potential impact of the LC3 project is very significant. After water, concrete is the most used material in the world. Any emissions reduction will have a substantial impact”, explains Professor Scrivener who heads the LC3 project. “LC3 can become an essential construction material, especially in fast-growing emerging economies where minimising environmental impact and resource depletion are a top priority”. It is estimated that using LC3 instead of regular cement can save up to 500 million tonnes of CO2 per year by 2050. “If we want to advance the sustainability of concrete – its cost, availability and environmental footprint – we have to act before demand increases exponentially”, says Scrivener.

India is the first country where LC3 is being tested, both in laboratory and in the field, on a large scale. Industrial scale pilot projects were implemented in Cuba and India and in both countries several structures were successfully built using the cement. The technology has generated also interest from leading cement and construction materials companies in Cuba, Europe, India, Thailand, South Africa, China and Brazil. India was selected for the size of its market and its growth potential, the wide availability of kaolin clays and the commitment of the Indian government to reduce CO2 emissions.

An LC3 project meeting will take place on 23 September at the Habitat Centre in Delhi, India, to define the next steps of the pilot phase.

Limestone Calcined Clay Cement – LC3 Project: This project is managed by the Ecole Polytechnique Fédérale de Lausanne (EPFL) in Switzerland, in collaboration with an international team of researchers from the University of Las Villas, Cuba, three prominent Indian Institutes of Technology; IIT Delhi, IIT Madras and IIT Bombay and technology incubation partner, Technology and Action For Rural Advancement, New Delhi with support from Dr. Anjan Kumar Chatterjee and various prominent cement companies in India.

After a preliminary study and a successful industrial pilot phase in Cuba, the LC3 consortium is testing the low carbon cement technology in India before it is introduced internationally. Initial field trials in India have shown promising results with equivalent or even improved results compared to traditional pozzolanic cements.