Cement Manufacturers Association (CMA)

53 Commercial Production and Future Prospects of LC3 (Limestone Calcined Clay Cement) Considering the New BIS Standard IS 18189:2023 Prof. Mainak Ghosal Affiliation: Mainak Ghosal Enterprises OPC Pvt. Ltd., Kolkata, West Bengal Corresponding Author: mainakghosal2010@gmail.com 07 Abstract The global cement industry faces an urgent challenge: reducing carbon emissions while meeting the rising demand for construction materials. Limestone Calcined Clay Cement (LC3) has emerged as a transformative solution, offering up to 40% reduction in CO ₂ emissions compared to Ordinary Portland Cement (OPC). The recent publication of the Bureau of Indian Standards specification IS 18189:2023 marks a watershed moment for LC3 adoption in India, providing the regulatory framework necessary for commercial-scale production. This paper examines the technical composition, production processes, economic viability, and environmental benefits of LC3 cement. Drawing on recent commercial production initiatives by JK Cement at Mangrol and the evolving regulatory landscape, we analyse the barriers and opportunities for widespread LC3 adoption in India. Our findings suggest that LC3 represents not merely an alternative to conventional cement, but a paradigm shift towards sustainable construction. The paper concludes with recommendations for policymakers, cement manufacturers, and construction professionals to accelerate the transition to low- carbon cement technologies. Keywords: LC3 cement, limestone calcined clay cement, IS 18189:2023, sustainable construction, carbon emissions reduction, BIS standard, green cement, clinker substitution 1. Introduction 1.1 Background and Context The cement industry accounts for approximately 8% of global anthropogenic CO ₂ emissions, making it a significant contributor of Industrial emissions . In India, where infrastructure development continues at an unprecedented pace, cement production is projected to grow significantly over the coming decades. This growth trajectory presents both a challenge and an opportunity: how can we meet construction demand while honouring our commitments under the Paris Agreement. Traditional Ordinary Portland Cement (OPC) production is inherently carbon intensive. For every tonne of cement clinker produced, approximately 0.9 tonnes of CO ₂ are released into the atmosphere. This emission stems from two sources: the calcination of limestone (releasing CO ₂ chemically bound in calcium carbonate) and the combustion of fossil fuels to achieve kiln temperatures exceeding 1450°C. Partial solutions like Portland Pozzolana Cement (PPC) and Portland Slag Cement (PSC) have achieved modest emissions reductions, but these blended cements still rely on clinker content of 65-70%.