Passivation behaviour of aluminium alloys in limestone calcined clay cement (LC³)

Limestone calcined clay cement (LC³) has emerged as a promising alternative to traditional Portland cement (PC), offering reduced carbon dioxide emissions and improved mechanical and durability-related properties. However, concerns persist regarding the durability of reinforced LC³ concrete, particularly its lower critical chloride threshold and carbonation resistance. To address this issue, aluminium alloys were suggested to be used as an alternative reinforcement. This study investigates the passivation behaviour of aluminium alloys in LC³ and compares it with that in PC. Electrochemical measurements indicate that LC³ paste exhibits higher resistance and forms a more compact film compared to PC paste, suggesting its more protective property. XRD, Raman spectroscopy, and SEM analysis provide insights into the chemical composition and thickness of the films formed on the surfaces of aluminium alloys. This study enhances our understanding of the passivation mechanisms of aluminium alloys in LC³, facilitating their potential application in LC³-based structures.