Corrosion behavior of steel reinforcement in magnesium silicate hydrate (M-S-H) concrete

Magnesium silicate hydrate (M-S-H) binder has been considered a promising alternative binder for engineering application. However, its low pH environment raises concerns for its adoption in steel reinforced concrete structures. To evaluate the corrosion behavior of steel reinforced M-S-H system under ambient and chloride environments, electrochemical tests were conducted. Additionally, phase formation, microstructure development, pore structure and solution chemistry were evaluated to better understand the corrosion mechanism. Corrosion resistance of the tested M-S-H system subjected to ambient environment was higher than that of the PC system because of significantly higher impedance of the bulk matrix, which was attributed to lower internal moisture, finer pore structure and lower conductivity of the pore solution in the M-S-H system. When subjected to cyclic chloride immersion, the M-S-H system exhibited higher corrosion rate, which was mainly due to its low pH and more electrolyte available on the steel surface.