Application of layered double hydroxides (LDHs) in corrosion resistance of reinforced concrete-state of the art

Hydrotalcite materials, also known as layered double hydroxides (LDHs), have strong ion exchange properties, and are widely used in the field of reinforced concrete corrosion protection. LDHs can improve the compactness and mechanical properties of concrete through physical and chemical effects, combined with its ion exchange performance, and jointly improve the resistance to chloride ion erosion. Compared with directly adding corrosion inhibitors, LDHs intercalating with corrosion inhibitors usually have multiple functions such as reducing corrosion inhibitor degradation, prolonging the long-term effect of corrosion protection, improving environmental alkalinity, and adsorbing corrosive ions. Among the preparation methods of LDHs intercalating with corrosion inhibitors, calcination-rehydration method has greater potential for large-scale application. This article reviews the preparation and intercalation modification methods of LDHs, their influence on the properties of concrete, the corrosion resistance mechanism and influencing factors of adsorption of chloride ion in concrete. Finally, the future research and application of LDHs in concrete are prospected, and the problems that need to be solved are put forward. It is expected to serve as a reference for the preparation of efficient, green and economical LDHs concrete, and provide more possibilities for the application of LDHs in practical concrete engineering.