A joint study by researchers in India, Cuba and Switzerland has found that production of limestone calcined clay cement, or LC3, can yield 40% fewer carbon emissions and about 20% less energy than production of ordinary portland cement. Researchers are particularly bullish on LC3’s potential to perform well in coastal areas.



In a project supported by the Swiss Agency for Development and Cooperation, a Sustainability Impact Assessment of Limestone Calcined Clay Cement (LC3) shows a reduction of nearly 40 per cent CO2 emissions and 20 per cent lower energy for production as compared to ordinary Portland cement.

At the same time, research 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 has shown that the concrete produced with this cement exhibits excellent strength and durability characteristics.



Universally, technologists have opined that one of the primary means of reducing the net carbon impact of concrete construction would be the use of less cement clinker in concrete, by the judicious use of by-product materials from mining, agriculture, and industry and minimise wastages through better construction techniques.

Limestone Calcined Clay Cement (LC3) is a blended cement incorporating Portland cement clinker, calcined kaolinitic clay, and limestone, in combination with gypsum. The extent of cement clinker is restricted to only 50 per cent, which implies a major reduction in CO2 emissions since the production of clinker involves the burning of limestone.

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.