MC-Bauchemie MC-RIM PROTECT-MR
The rigid, sulphate-resistant relining mortar for sewage channels, sand traps, and scraper trackways that ordinary coatings can’t survive.
What is it?
A one-component, fibre-reinforced, polymer-modified cementitious surface protection mortar rated Class R4 under EN 1504-3, built for highly sulphate- and chloride-resistant lining of mechanically stressed wastewater structures.
Where is it used?
Sewage and effluent treatment plant inlet channels, sand traps, scraper trackways, pump sumps, and drainage channel inverts — both new construction and rehabilitation of existing concrete, reinforced concrete, and prestressed structures.
Why use it?
It survives constant abrasive flow, biogenic sulphuric acid attack, and pH swings from 3.35 to 14 without softening or delaminating, giving a channel a genuinely structural repair layer instead of a cosmetic coat that fails within a monsoon or two.
How is it applied?
Mixed 100:15-16 (powder:water) in a forced or slow double-shaft mixer, then trowel-applied by hand or wet/dry sprayed in 2-3 passes to 8-10 mm standard thickness, followed by 5 days of moist curing under jute and plastic sheeting.
About MC-Bauchemie MC-RIM PROTECT-MR
MC-RIM PROTECT-MR is MC-Bauchemie’s rigid, fibre-reinforced repair-and-protection mortar built specifically for the parts of a sewage or effluent treatment plant that take a beating: inlet channels, sand traps, scraper trackways, and the invert of drainage channels where grit, turbulence, and constantly shifting pH chew through ordinary concrete and lighter renovation coatings within a few years. It is a one-component, polymer-modified, cement-bound system that goes on by hand with trowels and steel floats or, on larger jobs, by wet or dry (GUNMIX) spray, cures to a dense R4-class mortar under EN 1504-3, and is designed to be applied in two to three passes to build up an 8-10 mm total thickness (15 mm max) directly over sound, prepared concrete.
What sets it apart from a generic waterproof coating is that it is deliberately rigid rather than crack-bridging — MC-Bauchemie’s family logic separates “MR” (mechanically stressed, high-strength, abrasion-resistant) applications from the flexible or drinking-water grades in the same MC-RIM line. That makes it the wrong choice for a moving joint or a basement wall prone to hairline cracking, but the right one for a channel invert that needs 57 MPa compressive strength, sub-1 mm water penetration at 5 bar, and resistance across a pH 3.35-14 window without softening, delaminating, or losing its bond under constant abrasive flow. For Indian STPs and ETPs — municipal plants under AMRUT/Namami Gange upgrades as much as textile, pharma, and chemical-industry effluent units — this is the product you specify when a channel has already failed once and a cosmetic coating is not going to survive a second monsoon of grit-laden flow.
The technical insight
The number that matters most on this datasheet is the sulphate resistance figure: 0.08 mm/m expansion after 91 days by the SVA method. Sewage headworks generate hydrogen sulphide that oxidises to sulphuric acid on exposed concrete surfaces above the waterline — the single biggest reason inlet channels and sand traps fail years before their design life. A rigid, dense, fibre-reinforced matrix like this one resists that attack chemically (through the cement chemistry itself) rather than by simply keeping water out, which is why MC-Bauchemie pairs it with a documented pH tolerance down to 3.35. The trade-off is that this same rigidity is what makes it explicitly non-crack-bridging: the dynamic E-modulus of 27,500 MPa tells you this behaves like structural concrete, not like an elastomeric membrane, so it will not accommodate substrate movement the way a flexible coating would. That is a deliberate design choice for high-abrasion, chemically aggressive zones — but it means a specifier has to be honest about whether the existing structure is genuinely sound and static before choosing this over a movement-tolerant system.
Where it is used
- Inlet and drainage channel inverts in sewage and effluent treatment plants
- Sand trap and grit chamber lining where abrasive flow erodes conventional concrete
- Scraper trackways (paired with MC-DUR 1177 WV-A as the specified surface finish per the manufacturer’s TDS)
- Spiral pump hutch and pump sump lining subject to mechanical wear
- Rehabilitation of existing reinforced and prestressed concrete wastewater structures showing sulphate or chloride attack
- Screw pumping station coatings at >20 mm build-up around rotating screw conveyors
- Industrial ETP chambers in textile, pharma, and chemical plants with aggressive, variable-pH effluent
- New-construction protective lining for municipal STP channels ahead of commissioning
Key advantages
- Class R4 structural mortar under EN 1504-3 — genuinely load-bearing surface protection, not a thin cosmetic film
- Fibre reinforcement plus 57.3 MPa (28-day) compressive and 8.8 MPa flexural strength give real resistance to mechanical abrasion in channels and trackways
- Sulphate resistance verified to 0.08 mm/m at 91 days (SVA method) — built for the sulphuric-acid-generating conditions typical of sewage headworks
- Wide chemical tolerance (pH 3.35-14) covers the swing from fresh effluent to biogenic sulphide attack in a single specification
- Water penetration under 1 mm at 5 bar and a 0.26×10⁻¹² m²/s chloride migration coefficient — dense enough to genuinely seal the substrate, not just coat it
- Hand, wet-spray, or GUNMIX dry-spray application gives contractors flexibility across small repairs and full plant-scale re-lining jobs
- One-component, just add water (100:15-16 by weight) — no on-site resin metering or pot-life panic under a hot Indian sun
Limitations & considerations
- Rigid system with no crack-bridging capability — not suitable over substrates with active or movement-prone cracking without prior structural repair
- Not certified for potable water contact; drinking-water tanks need the PW-101/PW-301 grades from the same MC-RIM family instead
- Hand-mixing or partial-bag batching is explicitly disallowed by the manufacturer, so sites without a proper forced mixer will struggle to apply it correctly
- Cement-grey colour and mortar finish only — this is a functional lining, not a decorative or aesthetic coating
- Full 5-day moist curing and a temperature-controlled 5-30°C application window make it demanding to schedule well on exposed outdoor plant during peak summer or heavy monsoon
- As a 25 kg bagged mortar with fairly heavy coverage (roughly 14-17.5 kg/m2 at standard thickness), material cost per square metre runs meaningfully higher than a thin protective paint system
Selection & best practice
Treat substrate prep as non-negotiable — MC-Bauchemie’s own leaflet for the MC-RIM PROTECT range assumes a sound, saturated-surface-dry substrate with all laitance, oil, and unsound concrete removed by mechanical scarification before the first pass goes on; skipping this is the single most common cause of debonding in Indian wastewater repair jobs. Mix only in a forced or slow double-shaft mixer at 100:15-16 (powder:water by weight) for the full 5 minutes — hand-mixing or part-bag batches are explicitly disallowed by the manufacturer because they produce inconsistent density and strength. Build the coating in the specified 2-3 passes to reach 8-10 mm standard thickness, respecting the 5 mm minimum per step and 30-minute working time at 20°C; do not try to trowel the full thickness in one pass. Cure for a full 5 days under kept-moist jute and plastic sheeting (or switch to the matched MC-RIM PROTECT-C curing agent) and keep the work out of direct sun during application — both are called out explicitly because premature drying is the second major failure mode in this product family. Finally, respect the water-load waiting period (2 days at 10°C, 1 day at 20°C) before putting the channel back into service, and if the section is a scraper trackway, plan for the MC-DUR 1177 WV-A topcoat the datasheet specifies rather than leaving PROTECT-MR as the final wear surface.
Specifications
| System / Chemistry | One-component, polymer-modified, fibre-reinforced cementitious mortar |
| Fresh mortar density | approx. 2.03 kg/dm3 |
| Compressive strength | 43.5 MPa (7 days) / 57.3 MPa (28 days) |
| Flexural tensile strength | 7.4 MPa (7 days) / 8.8 MPa (28 days) |
| Sulphate resistance | 0.08 mm/m after 91 days (SVA method) |
| Water penetration depth | < 1 mm at 5 bar water pressure |
| Abrasion resistance | Class A6 per EN 13813 (Bohme-tested) |
| Coverage | 1.75 kg/m2 per mm thickness; standard layer 8-10 mm (15 mm max) |
| Standard / Classification | EN 1504-3, Class R4, Principle 3 (procedures 3.1 & 3.3); pack size 25 kg bags |
Industry use cases
Municipal STPs (AMRUT / Namami Gange upgrades)
Relining inlet channels and grit chambers in ageing sewage treatment plants where original concrete has degraded from years of sulphide exposure.
Industrial effluent treatment plants
Textile, pharmaceutical, and chemical-industry ETPs with variable, often acidic effluent chemistry that standard concrete or paint coatings cannot withstand.
Wastewater pumping stations
Screw pumping station and spiral pump hutch lining at the higher 20mm+ build-up the manufacturer specifies for that application.
Scraper trackway rehabilitation
Mechanically trafficked sludge-scraper rails in clarifiers, applied with the MC-DUR 1177 WV-A topcoat as the finished wear surface.
New-build sewage infrastructure
Protective lining specified into new RCC and prestressed concrete channel construction ahead of commissioning, rather than waiting for the first repair cycle.
Frequently asked questions
Is MC-RIM PROTECT-MR the same product as plain MC-RIM PROTECT?
Can MC-RIM PROTECT-MR be used inside a drinking water tank?
How much material do we need per square metre?
Does this coating bridge cracks in the existing concrete?
What surface preparation does it need before application?
Can it be sprayed, or does it have to be hand-applied?
How we position MC-Bauchemie MC-RIM PROTECT-MR
Within MC-Bauchemie’s own MC-RIM PROTECT range, PROTECT-MR sits as the mechanically-stressed, high-abrasion grade — pair it with MC-RIM PROTECT-C as the matched curing agent where wet-jute curing isn’t practical, and specify MC-DUR 1177 WV-A as the topcoat when the application is a scraper trackway, exactly as MC-Bauchemie’s own datasheet calls for. If the structure is a potable water tank rather than a sewage channel, the correct family member is MC-RIM PW-101 (vertical surfaces) or MC-RIM PW-301 (horizontal), not PROTECT-MR. Outside the MC-Bauchemie range, Fosroc’s Nitocote CM210 is a genuine consideration where flexibility matters more than raw abrasion resistance — see the note above — and generalist suppliers like Sika also offer cementitious repair coatings for wastewater infrastructure, though without the same EN 1504-3 Class R4 abrasion rating or documented sulphate-resistance data that MC-RIM PROTECT-MR carries on its published TDS.
Fosroc Nitocote CM210 — Nitocote CM210 is a flexible, crack-bridging elastomeric cementitious membrane rather than a rigid mortar, so a specifier would reach for it over MC-RIM PROTECT-MR when the structure has movement-prone cracking or needs potable-water-safe waterproofing, not when the channel needs MC-RIM’s rigid, high-abrasion, sulphate-resistant strength under mechanical wear.
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