MC-Bauchemie MC-Cor 1
A two-component, cement-bound corrosion-protection and bonding coat for exposed steel reinforcement, applied before patch repair to passivate the bar and key the new mortar to it.
What is it?
A factory-proportioned, two-part cementitious slurry from MC-Bauchemie that both inhibits corrosion on cleaned reinforcement and acts as a bonding bridge for the following repair mortar. Certified to EN 1504-7.
Where is it used?
Any concrete repair where reinforcement has been exposed by chloride attack or carbonation, from bridges and jetties to car parks, columns, beams and slabs.
Why use it?
It re-establishes a high-alkalinity film around the steel so freshly cleaned bar does not flash-rust, and it locks the repair mortar to the substrate so the patch does not debond later.
How is it applied?
Blast or wire-brush the bar to Sa 2.5, mix the liquid and powder to a lump-free paste, and brush a full even coat over every exposed face of the bar; overcoat while the slurry is still fresh and tacky.
About MC-Bauchemie MC-Cor 1
MC-Cor 1 belongs to the reinforcement-protection stage of a proper concrete repair sequence, and it earns its place because most patch repairs fail at the steel, not in the mortar. When a bar is broken out and cleaned, the surface is chemically raw and will begin to re-rust within hours in humid or coastal air. MC-Cor 1 is brushed onto that clean steel as a cement-based film, restoring the alkaline environment the bar originally sat in inside sound concrete. That high pH keeps the passive oxide layer stable, so corrosion is arrested at the point where the repair is being made rather than merely covered up.
The product is supplied as two matched components: a polymer-modified, corrosion-inhibiting liquid and a dry cement-based powder that are blended on site to a brushable consistency. Because the mix is cementitious rather than a film-forming paint, it stays chemically compatible with the concrete substrate and with MC-Bauchemie’s own repair mortars, and it doubles as a bonding slurry. Applied in its fresh, tacky state and overcoated before it dries, it creates a continuous mechanical and chemical link between old steel, old concrete and the new mortar. For engineers writing a repair specification to EN 1504, it is the reinforcement-protection line item (Principle 11) that sits directly ahead of the patch-repair mortar.
The technical insight
Corrosion of embedded steel is electrochemical: it needs an anode, a cathode, moisture and oxygen, and it runs fastest once the concrete’s natural alkalinity is lost to carbonation or its passive film is broken down by chloride ions. MC-Cor 1 attacks the chemistry rather than the symptom. Its cementitious matrix cures to a highly alkaline film in direct contact with the bar, re-passivating the steel by pushing local pH back above the threshold where iron stays in its stable oxide state. Unlike a barrier-only coating, it does not simply seal moisture out and hope for the best; it re-creates the protective condition that intact cover concrete would normally provide. The bonding function comes from the same cement chemistry: applied wet-on-wet, the slurry and the subsequent repair mortar hydrate together, so there is no cold-joint plane between coat and patch. This dual action is why it is placed at the interface, and why the overcoating window matters so much: bond and continuity are strongest when the mortar goes on while the slurry is still fresh.
Where it is used
- Corrosion protection of exposed reinforcement during patch repair of chloride- or carbonation-damaged concrete
- Priming and bonding coat ahead of MC-Bauchemie repair mortars on columns, beams and slabs
- Bridge decks, piers, crash barriers and other transport-infrastructure rehabilitation
- Marine and coastal structures, jetties and splash-zone elements where chloride ingress is severe
- Multi-storey and basement car park repairs subject to de-icing salts and vehicular wear
- Water-retaining and industrial structures where reinforcement has been cut out and re-exposed
- Balcony, facade and cantilever repairs on ageing residential and commercial buildings
- Localised anode treatment on cleaned bar to reduce the risk of new incipient-anode corrosion nearby
Key advantages
- Dual function in one product: corrosion inhibition and mortar bonding, saving a separate coat and a separate line item
- Cementitious, alkaline chemistry that re-passivates steel by restoring high pH rather than acting as a bare barrier
- Fully compatible with the concrete substrate and with MC-Bauchemie repair mortars for a monolithic patch
- Certified to EN 1504-7, so it can be written directly into a compliant repair specification
- Factory-proportioned two-part kit removes site guesswork on mixing ratios and dosage
- Simple stiff-brush application onto prepared bar, with no specialist spray equipment required
- Short overcoating window keeps the repair moving and suits fast-turnaround site programmes
- Water-based cement system with none of the strong-solvent handling issues of some epoxy primers
Limitations & considerations
- Performance depends entirely on surface preparation; bar must be cleaned to Sa 2.5 (bright steel) or the passivation is compromised
- It protects only the steel it actually coats, so every exposed face of every bar must be reached and covered
- The fresh, tacky overcoating window is short, so mixing and repair-mortar application have to be sequenced tightly
- As a two-component site mix it has a limited pot life once blended and must be used before it stiffens
- It is a repair-stage reinforcement primer, not a general anti-carbonation or surface-protection coating for finished concrete
- It does not remove existing chloride contamination from the surrounding concrete; badly contaminated cover concrete still needs cutting back to sound material
Selection & best practice
Start by breaking out all unsound and delaminated concrete until you reach solid substrate and fully expose the corroded steel, cutting back behind the bar where corrosion has undermined it. Grit-blast or power wire-brush every exposed bar to Sa 2.5 so the steel is bright and free of rust, scale and old concrete, then work quickly before flash-rust returns. Blend the liquid and powder components in the specified ratio to a smooth, lump-free, brushable paste, mixing only what can be used within the pot life. Using a stiff brush, apply a continuous, even film over the full circumference of each bar, including the back face and the transition onto the surrounding concrete edge; a second pass helps close pinholes. Then, while the slurry is still fresh and tacky within the overcoating window, apply the MC-Bauchemie repair mortar directly onto it so the two hydrate together. Protect the fresh work from rain, direct sun and drying wind, and cure the completed repair as the mortar’s data sheet requires. Always confirm exact mix ratio, coverage and overcoating times against the current product data sheet for the batch supplied.
Specifications
| Product type | Two-component cementitious corrosion-protection and bonding slurry |
| Components | Corrosion-inhibiting polymer liquid + dry cement-based powder |
| Standard | EN 1504-7 (reinforcement corrosion protection, Principle 11) |
| Function | Rebar passivation and mortar bonding coat |
| Surface preparation | Steel cleaned to Sa 2.5 per ISO 8501-1 |
| Application method | Stiff brush, full coat to all exposed bar faces |
| Overcoating | Apply repair mortar while slurry is fresh and tacky |
| Compatibility | MC-Bauchemie concrete repair mortar systems |
Industry use cases
Bridges & Transport Infrastructure
Reinstating corroded reinforcement on decks, piers and crash barriers, where the bar is passivated and bonded before high-strength repair mortar goes back on.
Marine & Coastal
Protecting freshly exposed steel in splash and tidal zones of jetties and sea-facing structures, where chloride-driven corrosion is aggressive and re-rusting is fast.
Car Parks
Repairing salt- and traffic-damaged decks and soffits, arresting corrosion at the bar so patch repairs to columns and slabs hold up under continued exposure.
Buildings & Facades
Treating rusting reinforcement in balconies, cantilevers and spalled columns of ageing residential and commercial blocks before making good the concrete.
Industrial & Water-Retaining
Rehabilitating tanks, channels and plant structures where reinforcement has been cut out and re-exposed and needs a compatible, alkaline protective coat.
Frequently asked questions
Is MC-Cor 1 a zinc-rich primer?
Does it also bond the repair mortar, or do I need a separate bonding coat?
How clean does the reinforcement need to be?
When do I apply the repair mortar over it?
Is it certified for specification work?
Can I use it with any repair mortar?
How we position MC-Bauchemie MC-Cor 1
MC-Cor 1 is the reinforcement-protection stage of a full MC-Bauchemie repair build-up: pair it with the brand’s Nafufill and MC-RocTec repair mortars for the patch, and with an MC-Bauchemie surface-protection or anti-carbonation coating over the finished, made-good concrete to slow future ingress. As an authorised distributor and applicator, Space Arc also supplies equivalent systems from other principals where a project standardises on a different brand, including Fosroc’s Renderoc repair mortar range and its zinc-rich rebar primers, and Sika’s concrete-repair line. If your specification calls for a galvanic, sacrificial rebar primer rather than a cementitious passivating one, the Fosroc route below is the honest alternative; if you want the coat to remain chemically part of the cementitious repair, stay with MC-Cor 1.
Fosroc Nitozinc Primer — Choose the Fosroc zinc-rich epoxy primer when the specification specifically calls for sacrificial galvanic protection of the bar rather than MC-Cor 1’s cementitious alkaline passivation, or when the surrounding repair is being built up in the Fosroc Renderoc system.
Related Concrete Repair products
Source MC-Bauchemie MC-Cor 1 for your project
Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.