Evaluation of the efficiency of the MasterLife CI 222 organic corrosion inhibitor additive for the protection of steel reinforcement bars in concrete

The article proposes a set of non-destructive electrochemical methods for evaluating the protective effect of the MasterLife CI 222 organic corrosion inhibitor additive, commercial product, as primary protection of reinforced concrete. The introduction of the additive increases the specific electrical resistance (rho) of the mortar based on the cement-sand mixture by 4-7 times relative to the control composition without the additive. At the same time, for the air-dry state of samples with the additives the rho values correspond to a low and insignificant risk of corrosion, whereas for samples saturated with a chloride solution, the risk of corrosion is moderate. It was found that the corrosion initiation of steel reinforcement bars placed in a mortar with an additive slows down by more than 12 times in the case of cement-sand mortar mixtures when periodically immersed in a 3% NaCl solution relative to the control composition without the additive. Depassivation was established for control samples already after the first immersion in a chloride solution. The effect is confirmed by simultaneous comparison of the results of the qualitative (measurement of the free corrosion potential of steel reinforcement) and quantitative (corrosion rate according to the method of polarization resistance) methods. Additionally, the samples with the additive had at least a 4-fold reduction in the corrosion rate. The instrumental control data were confirmed by the results of visual inspection, according to which the surface of reinforcement bars in the absence of the additive was characterized by more developed corrosion damage, the control samples of the mortar without the additive also had cracks, while the mortar with the inhibitor remained intact.