A Sustainability Impact Assessment of Limestone Calcined Clay Cement (LC3) in a project financed by the Swiss Agency for Development and Cooperation reveals a decrease of roughly 40% in CO2 emissions and 20% less energy for production when compared to standard Portland cement.

Simultaneously, research was 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 funding from the Swiss Agency for Development and Cooperation, India, has shown that the concrete produced with this cement exhibits excellent strength and durability characteristics.

Limestone Calcined Clay Cement (LC3) is cement that combines Portland cement clinker, calcined kaolinitic clay, and limestone with gypsum. Because the manufacturing of clinker entails the burning of limestone, the amount of cement clinker is limited to only 50 per cent, 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.