No longer cast in cement

Sometime in 2010, Shashank Bishnoi received a Skype call from Fernando Martirena, a Cuban researcher he'd met while working on his PhD in Switzerland. Martirena, who was looking at making better alternatives to cement, had developed a new type of cement. He asked the Professor of Civil Engineering at the Indian Institute of Technology (IIT) Delhi if he'd be interested in testing it in India. Bishnoi readily agreed.

They decided to ship to India samples of the cement — called LC³, for Limestone Calcined Clay Cement — but ran into logistical and Customs-related issues. That was when Bishnoi decided to make LC³ in India from scratch. "In the process, not only did we learn the method of production but also gained a lot of confidence in the capabilities of LC³," he says.

They ended up producing around 40 tonnes of LC³, with which they test-constructed a small building in Jhansi on the premises of TARA (Technology and Action for Rural Advancement), another collaborator in the project, in 2013.

Since then, many other test constructions have taken place. Researchers have also worked with commercial cement manufacturers to produce LC³. In the last decade, they have increased the suitability of LC³ for manufacturers and users and are now ready for commercial production.

"Millions of tonnes of LC³ are already being produced around the world and all this has happened in just 10 years of research," Bishnoi says, describing it as a "breakthrough" in cement technology.

LC³ has the potential to reduce cement manufacturing-associated CO₂ emission by up to 40%. It achieves this by reducing the amount of clinker in the cement and replacing it with limestone and calcined clay.