In-situ CO₂-reactive limestone calcined marine clay cement (LMC³) system fully derived from recycled solid waste

A groundbreaking in-situ CO₂-reactive LMC3 system was successfully developed using a novel two-step methodology combining thermodynamic modeling and experimental validation, which was derived from 100% recycling of a ternary waste system, incorporating incineration bottom ash (IBA), recycled concrete fines (RCF) and marine clay (MC). Using 40 wt% IBA and 60 wt% RCF as raw materials, C₂S-rich (71.5%) eco-clinker was successfully synthesized at 1200 °C. The optimized carbonation enabled the eco-cement system to in-situ form CaCO₃, demonstrating significant CO₂ reactivity and improving early strength while promoting subsequent hydration. After subsequent 28-day hydration, the synergistic enhancement of CaCO₃, C-(A)-S-H and mono-carboaluminate (Mc) phases ensured that the LMC3 system obtained superior compressive strength even with high calcined MC dosage (70%), exhibiting a higher value than OPC and state-of-the-art LC3 system. This advanced LMC3 system represents a promising direction to develop a low-carbon cement industry, contributing to environmental sustainability.