About MC-Bauchemie MC-Montan Injekt TR-X

MC-Montan Injekt TR-X sits in a category most site engineers don’t run into every day: an acrylate hydrogel, not a polyurethane or epoxy. Where MC-Bauchemie’s better-known MC-Injekt PU and epoxy resins are chosen to bond, fill and add strength, TR-X is chosen to seal. It ships as a genuine 2-component system — a base built from sub-components A1 and A2, and an initiator liquid built from either component B1 (a polymer dispersion) or plain water carrying component B2 — and it reacts on site into a soft, rubbery gel that can stretch to roughly two-and-a-half times its length (per DIN 52455) and swell by a further 100-120% on contact with water.

For Space Arc’s project engineers, that combination matters most on the two job types where Delhi NCR and Pan-India work keeps growing: metro and road tunnelling, and deep basements pushing into the water table. On a tunnel segment joint or a diaphragm-wall construction joint, ground movement, vibration from adjacent boring and intermittent hydrostatic pressure will crack a rigid grout over time; a soft, swelling gel keeps closing the gap instead of failing at it. We stock and inject TR-X ourselves rather than sub-contracting it out, because getting the initiator dosage and packer spacing right on a trial batch — not just reading the datasheet — is what decides whether a curtain-grouting programme actually stops water.

The technical insight

The datasheet is unusually transparent about a trade-off most manufacturers bury: MC-Montan Injekt TR-X behaves differently depending on what the initiator, component B2, is dissolved in. Mixed with plain water, viscosity drops to about 2.5 mPa·s and swelling rises to roughly 120%, favouring penetration into very fine ground. Mixed with the B1 polymer dispersion instead, viscosity rises slightly to about 15 mPa·s but elasticity nearly quadruples to around 270%, favouring joints that will keep moving for the life of the structure. The B2 dosage table — 0.2% up to 4% — then lets an applicator dial reaction time from about 2’30” to over 30 minutes at the same temperature. That’s effectively two adjustable variables, carrier and dosage, not one, for matching the gel to actual ground and joint conditions rather than forcing the ground to fit a fixed-speed product.

Where it is used

• Curtain grouting of fine-to-coarse loose soil ahead of tunnel boring, shaft sinking or deep excavation
• Elastic, swelling seal at precast tunnel segment (tubbing) circumferential and longitudinal joints
• Closing the annular gap and sealing cavities or imperfections between tunnel lining and surrounding rock
• Injection through embedded hose systems to seal new and existing construction joints
• Retrofit water-stopping at diaphragm wall and shaft joints below the water table
• Rock and coal-face consolidation with water cut-off in mine galleries and hydropower headrace tunnels
• Sealing active, water-bearing cracks and joints in masonry and concrete under one-sided water pressure
• Rehabilitation injection where earlier rigid grouts have cracked under continued joint or ground movement

Key advantages

• Very low viscosity (as low as ~2.5 mPa·s with water) reaches hairline fissures and fine soil pores that thicker PU or epoxy grouts miss
• Field-tunable reaction time — 2’30” to 32′ depending on initiator dosage and temperature — so one product handles fast or slow-moving ground
• High elasticity (up to ~270% with the B1 dispersion) lets the seal keep following joint movement instead of cracking like a rigid resin
• Swelling ratio of 100-120% on water storage gives the cured gel a self-sealing margin if it later dries out and is re-wetted
• DIN EN 1504-5 classification, DIBt approval and UBA drinking-water compliance make it acceptable on potable-water and regulated structures
• Rated water-tight to at least 7 bar, covering most metro, basement and pressure-tunnel hydrostatic loads
• High chemical resistance in highly alkaline pore water, so it holds up embedded in fresh or carbonating concrete
• Two mixing routes — water or B1 dispersion — give the specifier a genuine on-site choice between maximum penetration and maximum elasticity

Limitations & considerations

• It is a sealing gel, not a structural resin — it will not restore load-bearing capacity the way MC-Injekt PU or epoxy systems do
• Needs a proper 2-component injection pump and trained packer installation; it is not a cartridge-gun or hand-mixed retail product
• Reaction time is sensitive to water quality, temperature and B2 dosing accuracy, so a site trial batch is non-negotiable before full-scale work
• Four separate packs (A1, A2, B1, B2) add mixing steps and site logistics compared with single-pack injection resins
• As a soft, swelling gel it is not meant to fill large structural voids — that remains a job for cementitious or PU foam grouts
• Poor packer spacing or sequencing under-delivers the seal; execution quality matters as much as the material itself

Selection & best practice

Specifications

Industry use cases

How we position MC-Bauchemie MC-Montan Injekt TR-X

Within MC-Bauchemie’s own range, MC-Montan Injekt TR-X is the flexible, swelling counterpart to the firm’s PU and epoxy MC-Injekt line — specify TR-X where the joint keeps moving or the ground is water-bearing, and the PU/epoxy resins where the job is structural bonding or void filling. It also complements MC-Bauchemie’s waterstop and construction-joint systems, with TR-X handling retrofit or hard-to-access sealing that a cast-in waterstop can no longer reach. Fosroc is the other name Indian specifiers commonly ask about for injection work; Fosroc’s polyurethane and acrylic grout ranges compete well on straightforward crack and void injection, but few competing systems carry TR-X’s combination of documented gel-time tuning and a DIN EN 1504-5 swelling-seal classification purpose-built for moving joints in tunnelling and mining work.

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