Global insights into micro-macro mechanisms and environmental implications of limestone calcined clay cement (LC3) for sustainable construction applications

Limestone calcined clay cement (LC3) has gained attention in the research paradigm, and useful data is available in scattered form, necessitates comprehensive review to provide global insight into important research questions, i.e., micro-macro response, and environmental implications, keeping in view the future research directions. In this regard, the current article provides a comprehensive insight into LC3, focusing on its micro-macro mechanisms and critically examining different aspects such as chemical composition, hydration chemistry with special attention on phase assemblage, impacts of various salts and carbonation, rheological properties, mechanical behavior, high-temperature exposure, and compatibility with different admixtures. Additionally, this article explores the sustainable and environmentally friendly applications of LC3, with an emphasis on its economic and environmental advantages highlighted by pertinent data and lifecycle assessments (LCA). Comprehensive data was gathered from a micro-macro perspective considering SCMs from different regional sources, and comparisons were drawn with Ordinary Portland Cement (OPC). Further, comparative economic and environmental aspects for different grades of LC3 and OPC were evaluated and analyzed considering energy demand, cost-effectiveness, and energy efficiency. The micro-macro characteristics of LC3 are found to be majorly dependent on its constituent, particularly clinker composition and alumina content in SCMs, which varies regionally. This review study outlines the critical research directions, i.e., enhancement of mechanical behavior and rheology, incorporation of super plasticizers and waste materials for resource conservation, and improvement of carbonation resistance for durability to make LC3 a sustainable and first-choice cement.