Pore solution chemistry and corrosion in hydrated cement systems containing chloride salts: a study of cation specific effects

Abstract

The free chloride and hydroxyl ion concentrations of the pore electrolyte phase present in mature, hydrated cement pastes containing equivalent quantities of chloride ion, introduced into the mix water as NaCl or CaCl2, have been determined for two commercial cements. The corrosion rates of mild steel electrodes embedded in these materials have also been monitored by the method of linear polarization. It has been found that specimens containing CaCl2 are more aggressive than those with NaCl for the range of concentrations examined, but the effect appears to be a result of changes occurring in the early stages of hydration, rather than of longer term modifications in the pore solution chemistry.