MC-Bauchemie MC-Montan Injekt FR
A fast-reacting two-component PU resin that MC-Bauchemie built for one job: stopping running water and consolidating ground where ordinary crack-sealants run out of road.
What is it?
A two-component, low-viscosity polyurethane injection resin from MC-Bauchemie’s Montan (ground-engineering) range, cured with hardener MC-Montan Injekt F to form a rigid, closed-cell, waterproof resin body.
Where is it used?
Tunnel linings, diaphragm walls, foundation pits, rock strata and soil beneath rafts or base slabs, and running cracks/joints in concrete, masonry or natural stone under active water pressure.
Why use it?
It reacts with water itself, foaming shut against flowing leaks in seconds while still building genuine load-bearing strength, so it seals and strengthens the ground in one operation.
How is it applied?
Metered through a two-component injection pump (FS grade can run on a single-component pump) into packers of at least 4mm bore, per a pre-checked injection concept, with reaction speed chosen or accelerated to suit the water encountered.
About MC-Bauchemie MC-Montan Injekt FR
MC-Montan Injekt FR sits in a different bracket from the crack-injection resins most Indian waterproofing contractors handle daily. It isn’t a squeeze-into-a-hairline-crack product; it belongs to MC-Bauchemie’s Montan (ground-engineering) line, built for special foundation work and tunnelling, where water moves through rock fissures or granular soil under real hydrostatic head rather than through a leaking balcony upstand. The chemistry is a two-component polyurethane: component A (the FR, FN or FS resin, chosen by how fast you need it to react) reacts with component B, MC-Montan Injekt F, in a 1:1 ratio by volume, delivered through a metered injection pump rather than hand-mixed in a bucket. On contact with water it foams into a closed-cell, rigid mass that displaces the water and physically knits the surrounding rock or soil together, which is why it carries a genuine 50 N/mm² compressive rating rather than the soft, gel-like set typical of hydrophilic crack sealants.
For a Delhi NCR project team, the value shows up on metro and expressway tunnelling packages, deep basements in the high-water-table pockets of Noida and Gurugram, and any diaphragm wall or shaft with water actively running while the crew is still working. Space Arc supplies MC-Montan Injekt FR alongside the compatible MC-KAT 27 accelerator, injection packers and pump guidance as a specified package, because the resin only performs to its data-sheet numbers when the injection concept, packer spacing and pump capacity match the ground being treated. Reaction speed is the first lever engineers pull: FR reacts in 20-30 seconds for fast-flowing water, FN in about a minute for moderate seepage, and FS over roughly 60 minutes for slower, deeper grouting that can even run off a single-component pump.
The technical insight
The number worth pausing on is the 2-10x volume-expansion range on water contact, a function of counter-pressure, not a fixed foaming factor. Injected against unconfined water the resin expands aggressively to chase and fill voids fast; injected under the counter-pressure of dense rock or compacted soil it expands far less and packs in denser, which is exactly the condition under which its 50 N/mm² compressive and 25 N/mm² flexural tensile strength (ISO 604 / ISO 178) apply. The same resin behaves as an aggressive void-filler in open ground and a dense structural grout in confined ground, without changing chemistry. The FR/FN/FS system exists because reaction time has to match water velocity on site, not lab preference: a resin that gels in 20 seconds is exactly what a jetting leak needs, and exactly what a long gallery hole doesn’t.
Where it is used
- Sealing and consolidating rock, subsoil and structures in special foundation engineering and tunnelling
- Water-cutoff grouting of foundation pits, shafts and diaphragm walls under active seepage
- Stabilising building ground against seepage-driven ground loss around footings
- Increasing load-bearing capacity of soil under base slabs, rafts and bed-plates
- Sealing and reinforcing running cracks, joints and voids in concrete, masonry and natural stone
- Curtain grouting behind tunnel linings and rock consolidation ahead of excavation
- Void-filling and re-levelling under settled floor slabs
- Emergency shutoff of active water ingress before a permanent repair is scheduled
Key advantages
- Reacts on contact with water rather than being defeated by it, foaming shut against active leaks in seconds (FR grade)
- Cures to a genuinely load-bearing 50 N/mm² compressive strength, not a soft water-stop gel
- Low viscosity (~300 mPa·s) penetrates fine rock fissures and micro-cracks thicker cementitious grouts can’t reach
- Three reaction speeds (FR/FN/FS) plus an accelerator match set time to actual water velocity on site
- DIBt-assessed impact on soil/groundwater and REACH-assessed exposure, relevant for work near the water table
- Meets DIN 4102 building-material class B2 fire behaviour in the cured injection medium
- Can run as a hybrid programme alongside cement-suspension grouting for staged ground treatment
- 18-month shelf life in unopened packs gives flexibility to stock ahead of a tunnelling or piling package
Limitations & considerations
- Needs a metered two-component injection pump and ≥4mm packers; not a hand-mixed or pour-in product
- FR grade’s 20-30 second pot life leaves almost no working margin; misjudged timing wastes material or blocks the line
- Equipment must be flushed with MC-Verdünnung PU thinner promptly; set resin can only be chiselled out mechanically
- Application limited to a 5-40°C structure/ground temperature window
- Overqualified and needlessly costly for routine terrace, bathroom or podium waterproofing
- Brown and opaque once cured, always a concealed sub-surface treatment, never a visible finish
Selection & best practice
Treat this as an engineered injection programme, not a repair-in-a-can. Confirm the injectivity of the rock, soil or structure and set a written injection concept (packer layout, depth, sequence) before mobilising the pump; use packers or lances of at least 4mm bore so the fast FR grade doesn’t gel in the line. Keep structure/ground temperature within 5-40°C, dose MC-KAT 27 (up to 1% into component A) only when a faster set than the base grade is genuinely needed, and flush the pump with MC-Verdünnung PU thinner the moment work is interrupted beyond the resin’s pot life, since water-based cleaners do nothing to PU and cured material has to be chiselled out.
Specifications
| Chemistry / system | Two-component polyurethane (PU) reactive injection resin (component A + hardener MC-Montan Injekt F) |
| Mixing ratio (A:B) | 1:1 by volume |
| Density, mixed | approx. 1.13 kg/dm³ (DIN EN ISO 2811-1) |
| Dynamic viscosity | approx. 300 ± 50 mPa·s (DIN EN ISO 3219) |
| Reaction/application time (FR grade) | approx. 20-30 seconds (ASTM D7/487) |
| Volume expansion on water contact | 2-10x, depending on counter-pressure |
| Compressive strength | 50 N/mm² (ISO 604) |
| Flexural tensile strength | 25 N/mm² (ISO 178, 2% deformation) |
| Application temperature | 5°C to 40°C (structure/ground temperature) |
Industry use cases
Metro & tunnelling
Curtain grouting and rock consolidation behind TBM-driven tunnel linings and shaft walls on Delhi NCR underground infrastructure work
Deep basements
Cutting off active seepage through diaphragm walls and raft joints in high water-table zones of Noida and Gurugram
Foundation engineering
Consolidating loose or water-bearing ground beneath base slabs and bed-plates ahead of loading
Industrial retrofits
Emergency shutoff of running leaks in lift pits and pump rooms before a scheduled permanent repair
Hillside & hydro projects
Sealing and strengthening fissured rock strata in special foundation and slope-stabilisation work
Frequently asked questions
What’s the actual difference between the FR, FN and FS grades?
Can my crew apply this without a two-component pump?
Will it actually stop a live running-water leak?
Is it safe to use near a drinking-water source or the water table?
How long can I store it before a delayed tunnelling package?
Does Space Arc supply the pump, packers and accelerator with it?
How we position MC-Bauchemie MC-Montan Injekt FR
Within MC-Bauchemie’s range, MC-Montan Injekt FR is the heavy-ground sibling of the MC-Injekt family (MC-Injekt 2K, MC-Injekt FS, MC-Inject 1K) Space Arc already carries for general crack and joint injection; reach for those on a leaking slab or wall crack, and reserve Montan Injekt FR for rock, soil and tunnelling-grade work where load-bearing consolidation matters as much as the water-stop. Fosroc’s nearest packaged option is Nitofill WS60, and Sika lists comparable chemistry in Sika Injection-201 IN, though neither is marketed to the same rock/soil consolidation duty class as the Montan range.
Fosroc Nitofill WS60 — Specifiers needing only a quick, single-stage water-stop for a leaking construction joint or crack, without the ground/rock consolidation load rating of the Montan range, often reach for Nitofill WS60 instead.
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