Designing a Novel Nanocomposite: Ag Nanoparticles Deposited Layered Double Oxide of Calcium and Aluminium to Enhance Corrosion Resistance of Steel Bars in Simulated Concrete Pore Solution

Layered double hydroxides (LDH) have undergone extensive investigation, showing potential for application in the corrosion protection of reinforced concrete. However, the chloride consolidation ability of LDH is sensitive to the anions in the environment. In this paper, based on the isomorphic substitutes for cement hydration products (AFm), Ag was deposited on layered double oxide of calcium and aluminium (CaAl-LDO@Ag) to improve the stability of chloride capture. The anti-bacterial performance of CaAl-LDO@Ag was also tested. The results indicated a significant enhancement in chloride binding capacity due to Ag deposition. The mechanism of capturing chloride ions was mainly the structural memory effect of LDO and the combination of Ag+ and Cl−. On this basis, CaAl-LDO@Ag exhibited a better corrosion inhibition effect in the simulated concrete pore (SCP) solution, which was potentially attributed to the enhanced chloride threshold of steel bars. Moreover, antibacterial experiment demonstrated that CaAl-LDO@Ag effectively inhibits the reproduction of Escherichia coli (E. coli).