Towards Intelligent Concrete: Multi-Mechanism Self-Healing Systems with CO₂-Binding, Structural Restoration, and LCA–LCC Modelling

This study proposes a novel trimodal self-healing concrete system (TRI) that combines three synergistic mechanisms: in-situ geopolymerization using recycled C&D waste, enzyme-induced calcium carbonate precipitation (via carbonic anhydrase), and dual-trigger microcapsules responsive to pH and chloride ions. The developed composite demonstrates significant crack closure efficiency, mechanical recovery, and permeability reduction, confirmed through SEM and µCT imaging. A comprehensive life cycle assessment (LCA) and life cycle cost (LCC) analysis, in accordance with EN 15804+A2, reveals a 10.4% decrease in GWP_total and a 17% reduction in overall costs compared to reference concrete. The results suggest that the TRI system can extend infrastructure service life and reduce environmental impact while enabling integration with digital twin methodologies. The study introduces a framework for designing intelligent, circular, and self-restorative building materials