Corrosion evaluation of steel reinforcing in chloride containing cementitious materials relies on pore solution chemistry, chloride alkalinity balance, electrical resistivity or the saturated corrosion current density under a specified moisture regime. The latter descriptors are important, yet each of them represents a single parameter of electrochemical milieu around the imbedded steel. The saturated corrosion current density represents the magnitude of steel dissolution under the high level of electrolyte continuity but it does not represent the duration of such process occurring during the wet and dry periods. In this paper, the retained corrosion activity of the reinforcing steel in Ordinary Portland Cement (OPC) and alkali-activated slag mortars will be evaluated by converting the saturated corrosion current density into a moisture residence burden. The eleven mixtures of chloride containing mortars will be assessed by chloride-to-hydroxide molar ratio, pore-structure exposure coefficient, resistivity exponent, moisture sensitivity exponent, saturated electrical resistivity, and saturated mortar corrosion current density. Moisture histories will include wet-marine (with high electrolyte continuity), alternated wet–dry (with moderate electrolyte continuity) and drying (with low electrolyte continuity). For the alkali-activated slag mixtures with a moisture sensitivity exponent of 2.1, the attenuation factor decreases from 0.726 for wet-marine exposure to 0.114 for drying exposure. For OPC-0.36-Cl1.8 with the same exponent, the attenuation decreases from 0.838 to 0.268. NH-A2.5-Cl1.8 mixture has the largest value of the burden in all moisture histories, being equal to 1.597, 0.825, and \SI{0.250}{\micro\ampere\per\square\centi\metre} for wet-marine, alternating and drying exposures. OPC-0.36-Cl1.8 mixture retains 31.9\% of its burden under the drying exposure while the alkali-activated slag mixtures retain 15.7\%. The obtained results confirm that the severity of steel corrosion in chloride containing mortars should be estimated by interaction of chloride alkalinity balance, resistivity, saturated current density and moisture residence.

reinforcement corrosion,chloride-induced corrosion,ordinary Portland cement,alkali-activated slag,electrical resistivity,corrosion current density,wetting and drying,moisture residence,steel passivation