Effect of MgAl-NO2 LDHs inhibitor on steel corrosion in chloride-free and contaminated simulated carbonated concrete pore solutions

This paper aims to examine the corrosion protection of reinforcing steel in concrete due to carbonation alone and the coupled action of chloride penetration and carbonation by MgAl-NO2 layered double hydroxides (LDHs), which was synthesized by calcination rehydration method. The results reveal that MgAl-NO2 LDHs have a better inhibition effect on the steel corrosion by carbonation alone than the coupled action of chloride penetration and carbonation. The inhibition mechanism for carbonation alone is mainly attributed to the alkalinity increase and NO2- release. The Cl- uptake additionally contributes to the corrosion inhibition for the coupled action of chloride penetration and carbonation.