Limestone Calcined Clay Cement (LC3) Systems: Advancements in Properties, Sustainability Potential, and Emerging Research Directions

The cement industry is a major contributor to global CO2 emissions, primarily due to energy-intensive clinker production. Limestone Calcined Clay Cement (LC3) has emerged as a promising low-carbon alternative to traditional Portland cement. It reduces the clinker factor and associated emissions, providing substantial environmental and economic benefits. This review explores the production process of LC3, emphasizing thermal and mechanical aspects of calcination, and grinding and blending stages critical to performance. The hydration mechanism is analyzed by detailing key chemical reactions, hydration products, and microstructural characteristics. Furthermore, the review discusses the influence of various clay types on reactivity and final properties. Key properties of LC3, such as durability, mechanical performance, and fresh-state behavior, are evaluated. Technical challenges and opportunities for large-scale implementation are examined alongside environmental and economic implications. Finally, future research directions are proposed to address limitations and enhance the deployment of LC3 technologies in sustainable construction.