The influence of chlorides on corrosion behavior of carbon steel in slag-based geopolymer pore solution

The electrochemical behavior and surface characteristics of carbon steel are investigated to clarify the influence of Cl- on its corrosion resistance in simulated slag-based geopolymer pore (SSGP) solution in this study. Adsorption layer (about 40-60 nm) forms in Cl- -containing SSGP solution, thus maintaining the passivity of the reinforcement in SSGP solution with 3.5 wt % and 7 wt % Cl-. The passive film contains FeO/FeS internal film and FeOOH/Fe2O3 external film, exhibiting slightly reduced passive film resistance in Cl- -containing SSGP solution. Further, the critical Clcontent in SSGP solution is dramatically larger than that in simulated cement pore solution, which is associated with the existence of adsorption layer and subsequently competitive adsorption of silicates.