Biomineralized coating inhibiting corrosion of reinforcement in cracked concrete: A study in simulated aggressive environments

Microbial induced carbonate precipitation (MICP) has been widely applied in structural repair, especially for self-healing of concrete cracks. In this study, the idea to inhibit reinforcement corrosion upon concrete cracking by coating with MICP as a straightforward way was proposed and validated by a simulated experimental assessment. Two typical environments of carbonation and coupling of carbonation with chlorides were firstly simulated by the synthesis solution method. An organic-inorganic biomineralized coating formed on the steel surface. In the carbonation environment, the coating effectively protected the passive film that the corrosion inhibition efficiency was over 95 % up to 12 days and the corrosion current density maintained within 0.1 mu A.cm- 2 throughout. An addition of chlorides resulted in a strong anodic control mode of the electrochemical process owing to the hindrance of chloride diffusion by the coating. However, the corrosion inhibition efficiency of the coating declined from 90 % to 70 % after 9 days owing to the high penetrability of chlorides.