MC-Bauchemie MC-Crete MCI Migrating Corrosion Inhibitor
A zero-chloride, amino-alcohol migrating corrosion inhibitor that is dosed into fresh concrete to protect embedded reinforcement long before chlorides ever reach the steel.
What is it?
A liquid migrating corrosion inhibitor (MCI) admixture based on organic amino-alcohol chemistry, added to fresh concrete to slow the onset of rebar corrosion in aggressive environments.
Where is it used?
Coastal and marine structures, urban parking decks, bridge decks and substructures, sea walls and any reinforced or prestressed concrete facing chloride or carbonation attack.
Why use it?
It raises the chloride threshold the steel can tolerate and keeps working through the pore structure for the service life of the structure, buying years of durability without altering the mix design.
How is it applied?
Dosed at roughly 0.5 to 2.0 litres per 100 kg of cementitious content, added at the batching plant or truck and mixed thoroughly before placing, with no change to normal placing and curing practice.
About MC-Bauchemie MC-Crete MCI Migrating Corrosion Inhibitor
MC-Crete MCI from MC-Bauchemie is a migrating corrosion inhibitor that is added to concrete at the mixing stage rather than painted on afterwards. Its chemistry is built around organic amino alcohols, including dimethyl ethanolamine and amide-amine compounds, and it carries no chloride whatsoever. That last point matters more than it sounds: many older accelerators and set-modifiers introduced chloride into the mix, which is exactly the ion you are trying to keep away from the steel. MC-Crete MCI does the opposite, laying down a defence for the reinforcement from the day the concrete is poured.
What sets a migrating inhibitor apart from a simple film-former is mobility. Once in the hardened matrix, the active molecules travel through the concrete in both the vapour phase and the aqueous (pore-water) phase, seeking out the reinforcement even in zones the liquid never directly touched. When they reach the steel they adsorb onto it and build a thin, self-repairing monomolecular film. For engineers designing 100-year infrastructure in Delhi NCR and along India’s long coastline, that combination of zero chloride and active migration is why MC-Crete MCI is specified where ordinary concrete cover alone is no longer considered enough.
The technical insight
Reinforcement stays passive as long as the concrete around it is alkaline and the chloride level at the steel stays below a critical threshold, usually taken as around 0.4 percent chloride by mass of cement. Once chlorides diffuse past that point, the passive layer breaks down and pitting corrosion begins. MC-Crete MCI works on two fronts against this. First, it is a mixed inhibitor, acting on both the anodic and the cathodic sites of the corrosion cell, so it does not depend on getting the dosage of a single-site anodic inhibitor exactly right (an underdosed anodic-only inhibitor can actually accelerate pitting). Second, the amino-alcohol molecules migrate to the rebar and form an adsorbed film that competes with chloride ions for the steel surface. The practical result is that the chloride concentration the steel can tolerate before corrosion initiates is pushed substantially higher, on the order of 2.5 to 4 times the untreated threshold, roughly from 0.4 percent up towards 1.0 to 1.5 percent by cement mass. Because the inhibitor keeps migrating through the pore network, it continues to top up protection at the steel over time rather than being consumed in a single reaction, which is what makes it a service-life measure and not just a placement-day one.
Where it is used
- Reinforced concrete for coastal and marine structures exposed to salt spray and tidal cycling
- Bridge decks, piers and substructures subject to de-icing salts or seawater
- Urban and multi-storey parking structures where run-off carries chlorides
- Post-tensioned and prestressed concrete, where zero chloride content is mandatory
- Sea walls, breakwaters and offshore or splash-zone elements
- Long-design-life infrastructure targeting 75 to 100 year durability
- Precast elements destined for aggressive exposure classes
- New construction where enhanced cover-zone durability is specified over standard concrete
Key advantages
- Zero chloride content, making it safe for prestressed and post-tensioned concrete
- Migrates in both vapour and aqueous phases to reach steel the liquid never directly wetted
- Raises the critical chloride threshold roughly 2.5 to 4 times versus untreated concrete
- Mixed anodic and cathodic action avoids the underdosage risk of anodic-only inhibitors
- Negligible effect on compressive strength, setting time and workability of the mix
- Added at the batching plant with no change to normal placing or curing routines
- Delivers durability that is built in from day one rather than reliant on later maintenance
- Complements increased cover and low-permeability mixes as part of a layered durability strategy
Limitations & considerations
- It is a preventive admixture for new concrete, not a repair mortar or a cure for steel that is already actively corroding
- Protection depends on correct dosage for the exposure class, so the mix must be batched and verified accurately
- It reduces corrosion risk but does not replace adequate cover, low water-cement ratio and sound compaction
- On existing distressed structures a surface-applied inhibitor or patch-repair system is the appropriate route instead
- Benefits are long-term and durability-based, so they are not visible on the finished surface and rely on correct specification
- As a liquid admixture it must be dispensed and mixed properly; poor batching control undermines uniform protection
Selection & best practice
Confirm the dosage against the design exposure class before batching. For most reinforced concrete a dose in the range of 0.5 to 2.0 litres per 100 kg of cementitious content is used, with the higher end reserved for severe and extreme chloride exposure. Add the inhibitor to the concrete at the batching plant or into the truck along with the mixing water and mix thoroughly so it is uniformly distributed; it should not be poured onto placed concrete. Because MC-Crete MCI has negligible effect on setting and workability, no change to normal placing, finishing or curing is needed, but good curing and proper cover remain essential because the inhibitor works alongside a dense, low-permeability matrix rather than instead of one. Keep a record of the dose per cubic metre for the project QA file, and for structures with existing steel exposed during construction, prime that steel separately before casting. Always cross-check the dose and compatibility against the current MC-Bauchemie product data sheet for the specific mix and exposure.
Specifications
| Inhibitor type | Migrating corrosion inhibitor (MCI) admixture |
| Chemistry | Organic amino alcohols (dimethyl ethanolamine, amide-amine compounds) |
| Chloride content | Zero |
| Inhibition mechanism | Mixed anodic and cathodic; monomolecular adsorbed film on steel |
| Migration | Vapour phase and aqueous (pore-water) phase diffusion |
| Typical dosage | 0.5 to 2.0 litres per 100 kg cementitious content |
| Chloride threshold shift | Raised roughly 2.5 to 4x (approx. 0.4% up to 1.0-1.5% by cement mass) |
| Effect on fresh/hardened concrete | Negligible effect on strength, setting time and workability |
| Relevant standards | IS 456 (severe/extreme exposure), IS 1343 (prestressed, zero-chloride) |
Industry use cases
Marine & coastal infrastructure
Sea walls, jetties and splash-zone decks along India’s coast, where chloride-laden air and tidal wetting attack reinforcement that increased cover alone can no longer fully protect.
Bridges & transport
Decks, piers and substructures where the inhibitor extends service life against chloride ingress and supports 100-year design targets on major structures.
Parking & commercial buildings
Multi-level car parks in Delhi NCR and other cities where vehicle run-off and salts concentrate on decks and ramps, dosed into the mix for durable slabs.
Prestressed & precast works
Post-tensioned girders and precast marine elements where zero chloride content is non-negotiable and migrating protection safeguards high-stress strand.
Durability-critical new build
Water-retaining and industrial structures specified for extended service life, where MCI is combined with low-permeability mixes as a layered defence.
Frequently asked questions
Is MC-Crete MCI added to the concrete or painted on the surface?
Does it contain any chloride?
Will it change my mix design, strength or setting time?
How much do I dose per cubic metre?
Can it stop corrosion that has already started in an old structure?
Does it remove the need for proper cover and good curing?
How we position MC-Bauchemie MC-Crete MCI Migrating Corrosion Inhibitor
MC-Crete MCI is the choice when you want corrosion protection engineered into the concrete at the mixing stage for aggressive, chloride-rich exposure. It sits naturally alongside the rest of the MC-Bauchemie durability range: pair it with the Nafufill repair mortars and the Nafufill MK active corrosion-protection coating when you are refurbishing existing elements, so new work and repairs share one specification. Where a project instead needs to shield exposed rebar during patch repairs, our Fosroc line covers that gap with a zinc-rich galvanic primer. Space Arc supplies MC-Bauchemie, Fosroc, Sika and Dr. Fixit corrosion and durability systems across Delhi NCR and Pan-India, so we can specify a single coherent package rather than mixing incompatible chemistries.
Fosroc Nitozinc Primer — Choose the Fosroc option when you need to protect already-exposed reinforcement during a patch repair, since it is a zinc-rich galvanic primer applied directly to the steel rather than an admixture for new concrete.
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