Corrosion behavior of the reinforcement in chloride-contaminated alkali-activated fly ash pore solution

Corrosion performance of the reinforcement was dramatically affected by chemical compositions of pore solution in alkali-activated fly ash. In this study, the electrochemical behavior and surface properties of reinforcement were characterized in chloride-contaminated simulated alkali-activated fly ash pore (SAFP) solution. The results indicated that due to the high alkalinity and formation of zeolite-like adsorption layer (about 20 nm), the reinforcement was still in passive state and exhibited high corrosion resistance in chloride-contaminated SAFP solution. However, the protective effect of passivation film (consisted of mainly FeOOH outer film and FeO inner film) and corrosion resistance of the reinforcement were reduced by chlorides. Further, the chloride threshold in SAFP solution was 10 times larger than simulated cement pore solution, due to the competitive adsorption between OH-/silicates and chlorides.

Automated summary

The corrosion performance of reinforcement in alkali-activated fly ash is significantly affected by the presence of chloride ions. Despite the high alkalinity and formation of a zeolite-like adsorption layer in the pore solution, the presence of chlorides can reduce the protective effect and corrosion resistance of the reinforcement.