What is a migrating corrosion inhibitor (MCI)?

It is a chemical admixture that, when added to concrete, migrates through the pore solution and forms a protective film on the surface of steel reinforcement to prevent corrosion.

Does using an MCI affect concrete strength?

It should not significantly. As per Table 1, the 7 and 28-day compressive strength of concrete with the MCI must be at least 90% of the control concrete without the admixture.

How is the corrosion-inhibiting performance of an MCI evaluated?

As per Clause 6 and Table 2, its performance is evaluated by electrochemical tests (specified in Annex B) where the corrosion current density of steel in concrete with the MCI must be 10% or less than that of the control sample.

Are there limits on setting time when using an MCI?

Yes, according to Table 1, the initial setting time must be within -60 minutes to +90 minutes of the control mix, and the final setting time must be within +90 minutes of the control mix.

IS 14958

: 2001

Migrating corrosion inhibitors - Specification

CurrentSpecializedSpecificationMaterials Science · Admixtures and Chemical Products for Concrete

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This standard specifies the requirements for migrating corrosion inhibitors (MCIs) used as admixtures in concrete. It covers physical, chemical, and performance criteria to ensure the inhibitor does not harm concrete properties while effectively reducing the corrosion rate of embedded steel reinforcement.

Specifies requirements for migrating corrosion inhibitors used to protect steel reinforcement in concrete.

Quick Reference Values

Compressive Strength at 7 & 28 days≥ 90% of control mix

Initial Setting TimeNot more than 60 min before or 90 min after control mix

Final Setting TimeNot more than 90 min after control mix

Corrosion Current Density (icorr)≤ 10% of control specimens when tested as per Annex B

Chloride contentMax 0.05 percent by mass

Practical Notes

MCIs are particularly effective in new construction in corrosive environments (e.g., coastal areas) and in the repair of chloride-contaminated structures.

Always conduct compatibility tests with the specific cement and other admixtures being used, as interactions can affect performance and setting times.

The effectiveness depends on the inhibitor's ability to migrate through the concrete pore structure, so achieving a dense, well-compacted concrete is crucial.