Life-cycle sustainability assessment of limestone calcined clay cement (LC³) as sustainable alternative in concrete structures

Over 25% of the world's CO₂ emissions are caused by the construction and demolition of buildings. In contrast with conventional cement, this study investigates the cost-effectiveness, environmental impact, production, and techno-economic sustainability of limestone calcined clay cement (LC³). The results indicate that 50% LC³ can be added to concrete, potentially significantly reducing carbon emissions in the construction industry. Furthermore, in this context, LC³ is a sustainable alternative that uses a mixture of unburned limestone and calcined clay (produced by burning clay at 800 degrees Celsius with 40–60% kaolinite, which is sometimes found as waste in kaolinite mines) to replace about 50% of standard cement. This combination can significantly improve the concrete's long-term durability while retaining its strength, improving the structure's service life compared to ordinary Portland cement. The sustainability impact assessment unequivocally demonstrates that the production of LC³ uses about 20% less energy and reduces CO₂ emissions by more than 40% compared to conventional Portland cement (OPC). In conclusion, to improve the sustainability of concrete in terms of cost, availability, and environmental impact, all its material procurement must be completed rapidly before demand increases, as this sustainable alternative LC³ production is still significantly less expensive. Therefore, the construction industry must embrace circular, resource-efficient, and sustainable practices to reach a net-zero future.