MC-Bauchemie MC-DUR 2496 CTP Tunnel
A two-component polyurethane surface-protection sealer purpose-built for tunnel linings, certified to EN 1504-2 and engineered around ÖBV, ASTRA and ZTV-ING Part 5 tunnel standards.
What is it?
A two-component, low-solvent, fast-curing special-polyurethane sealer used as a rigid (non-crack-bridging) surface-protection coating over mineral concrete substrates.
Where is it used?
Inner shells of road, rail and hydro tunnels; non-trafficked exterior tunnel portals, headwalls and approach structures; de-icing-salt spray and splash zones; metro cut-and-cover concrete.
Why use it?
EN 1504-2 certified, curing largely independent of ambient temperature and moisture, high abrasion and scratch resistance, UV/weathering stable, and rain-resistant within 30 minutes so tunnel closures stay short.
How is it applied?
Mixed 100:55 (base:hardener) by weight, then rolled crosswise in two coats or airless-sprayed over a cured epoxy primer such as MC-DUR 1200 VK or MC-DUR 1177 WV-A, with an optional oven-dried quartz sand broadcast (0.2-0.6 mm) for anti-skid duty.
About MC-Bauchemie MC-DUR 2496 CTP Tunnel
MC-DUR 2496 CTP Tunnel belongs to MC-Bauchemie’s MC-DUR family of special-polyurethane sealers, but it is a distinct, tunnel-specific formulation rather than a relabelled version of the company’s general-purpose MC-DUR 2496 CTP flooring sealer. It is built and tested against the design codes that actually govern tunnel surface protection in Europe — Austria’s ÖBV guideline, Switzerland’s ASTRA standard, and Germany’s ZTV-ING Part 5 “Tunnel” — and carries EN 1504-2 certification for protection principles 1, 2 and 8. That combination matters because tunnel interiors present a harder set of conditions than a typical facade or car park deck: constant dampness, restricted ventilation, diesel-exhaust carbonation load, and, near portals and approach ramps, heavy de-icing-salt spray through winter. The product’s cure chemistry is stated to be largely independent of temperature and moisture, which is what allows contractors to actually get a usable film in a cold, humid bore rather than waiting out weather windows.
For Indian project teams, the relevance is growing rather than shrinking. Himalayan highway tunnelling (NH corridors, strategic border roads), metro cut-and-cover sections, and hydropower headrace/tailrace linings are all producing more exposed tunnel concrete that needs long-term carbonation and abrasion protection, and several of these projects already specify European tunnel codes or EN 1504 compliance in their protective-coating schedules. As an authorised MC-Bauchemie distributor and applicator for Delhi NCR and pan-India, Space Arc Engineering sources this product through the manufacturer’s own supply chain, which matters for a specialist import: correct batch traceability, the right primer pairing confirmed against the current datasheet, and technical backup during specification and site inspection rather than a generic grey-market tin with no application support behind it.
The technical insight
The property that sets MC-DUR 2496 CTP Tunnel apart from a generic PU topcoat is the deliberate split between its two diffusion values: resistance to carbon dioxide ingress exceeds an equivalent air layer of 50 m at 150 micron dry film, while resistance to water vapour stays under 4 m at the same thickness. In plain terms, the film is dense enough to slow carbonation-driven corrosion of reinforcement, yet open enough to let residual moisture trapped in young or damp tunnel concrete escape outward without blistering or delaminating the coating — a common failure mode with fully vapour-tight epoxy systems used in the same setting. Combine that with a cure mechanism the datasheet states is “not related to temperature and moisture influence,” and the product is workable in the cold, damp, poorly ventilated conditions typical of an active tunnel bore, where many two-component systems slow to a crawl or blush on damp substrates. This is also why the manufacturer routes the product through ÖBV, ASTRA and ZTV-ING Part 5 tunnel-specific test regimes rather than a general building-facade coating standard.
Where it is used
- Inner shell surface protection of road and rail tunnel linings per ÖBV, ASTRA and ZTV-ING Part 5
- Non-accessible, non-driven-on exterior surfaces such as tunnel portals and headwalls
- De-icing salt spray and splash zones at tunnel approach ramps and portal aprons
- Carbonation-retarding topcoat over exposed RC surfaces in metro cut-and-cover sections
- Concrete lining protection in hydropower headrace and tailrace tunnels
- Refurbishment recoat over existing aged epoxy or PU tunnel coatings
- Anti-skid pedestrian coating (with quartz broadcast) on service walkways and galleries inside tunnels
- Surface protection of mineral substrates per EN 1504-2 principles 1, 2 and 8
Key advantages
- EN 1504-2 certified for principles 1, 2 and 8 (procedures 1.3, 2.3, 8.3), giving specifiers a documented compliance basis for tunnel works
- Cure is largely independent of ambient temperature and humidity, so application is feasible in cold, damp tunnel-bore conditions
- Short 2-12 hour recoat window and rain resistance within 30 minutes keep tunnel possession/closure times tight
- EN ISO 13300 wet-abrasion class 1 and high scratch resistance suit the dust, tyre spray and foot traffic near tunnel walls
- Vapour-permeable yet carbonation-retarding film reduces blistering risk on damp or young concrete versus fully sealed epoxy systems
- UV- and weathering-stable glossy finish with LRV class 70 improves surface reflectivity, supporting tunnel lighting efficiency
- Resistant to elevated temperatures, frost and de-icing salts, matching the exposure at portals and hill-road approaches
- Roller, paint or airless-spray application, with a proven quartz-broadcast route for anti-skid pedestrian zones
Limitations & considerations
- Rigid, non-crack-bridging system — not suited to substrates with live or moving cracks, which need a flexible/elastomeric coating instead
- Requires a compatible cured epoxy primer (e.g. MC-DUR 1200 VK or 1177 WV-A); it is not a standalone, self-priming product
- Application window is narrower than water-based coatings: substrate/air temperature 2-40°C and material temperature 15-40°C, with the dew point strictly observed
- Explicitly intended for non-accessible, non-driven-on surfaces, not for vehicular trafficked tunnel carriageways
- Roughly 120-minute pot life after mixing base and hardener demands disciplined batching and trained applicators on site
- As an imported specialist system it carries a cost and lead-time premium over generic acrylic or epoxy anti-carbonation coatings where full tunnel-grade performance isn’t actually needed
Selection & best practice
Prepare and prime the substrate strictly per MC-Bauchemie’s General Application Advice leaflets before touching this product — the surface-protection-systems leaflet, and the fine-fillers leaflet where Nafufill R3 FM or similar levelling is used underneath. Mix the full pre-packed base:hardener ratio (100:55 by weight) with a slow-speed mixer, then re-pot into a clean container and mix again; never eyeball partial batches. Apply in two crosswise, strip- and lap-free coats with a short-pile roller (or airless spray for large tunnel runs), leaving 2-12 hours between coats and never processing in rain, frost, or onto a substrate carrying a closed water film. For anti-skid duty, broadcast oven-dried 0.2-0.6 mm quartz sand into the wet second coat at roughly 400 g/m² and roll it in before it skins over. Keep site records of batch numbers and mixing times — the datasheet itself flags that colour and gloss can vary slightly batch to batch — and always run a test patch to confirm coverage on the actual substrate porosity before committing to the full tunnel run.
Specifications
| Chemistry | Two-component, low-solvent, special-polyurethane sealer |
| Mixing ratio | 100 : 55 (base : hardener), parts by weight |
| Density | approx. 1.35 kg/dm³ at 20°C / 50% RH |
| Working time (pot life) | approx. 120 minutes at 20°C / 50% RH |
| Overworkable after | 2-12 hours |
| Application conditions | Air/substrate 2-40°C; material 15-40°C; above dew point |
| Consumption | 130-260 g/m² (approx. 80-160 micron dry film) |
| Standards / certification | EN 1504-2 (principles 1, 2, 8); EN ISO 13300 wet-abrasion class 1; EN 13501-1 class C-s1,d0; ÖBV / ASTRA / ZTV-ING Part 5 Tunnel |
| Pack sizes | 10 kg and 30 kg units |
Industry use cases
Highway tunnels
Inner-shell PU sealer over an epoxy primer on hill-road tunnel linings exposed to vehicle exhaust carbonation and winter de-icing-salt spray at portals.
Metro / rail infrastructure
Carbonation-retarding topcoat on cut-and-cover tunnel segments and station box concrete where long-term reinforcement protection is specified.
Hydropower
Protective sealing of headrace and tailrace tunnel concrete linings subject to abrasion and periodic water contact.
Tunnel maintenance / refurbishment
Recoating aged epoxy or PU tunnel linings during scheduled traffic-closure maintenance windows, using the product’s fast recoat cycle.
Service walkways and galleries
Anti-skid pedestrian coating inside tunnels, built up with a broadcast quartz layer over the standard two-coat sealer application.
Frequently asked questions
Is MC-DUR 2496 CTP Tunnel the same product as the standard MC-DUR 2496 CTP flooring sealer?
Can this be applied directly onto bare tunnel concrete without a primer?
Will it bridge hairline or shrinkage cracks in the tunnel lining?
How quickly can we recoat or reopen after application?
What pack sizes and colours are available?
Does Space Arc stock this in India, and what’s the lead time?
How we position MC-Bauchemie MC-DUR 2496 CTP Tunnel
MC-DUR 2496 CTP Tunnel sits inside MC-Bauchemie’s own surface-protection system rather than standing alone: it is designed to run over epoxy primers MC-DUR 1200 VK or MC-DUR 1177 WV-A, pairs with MC-DUR 1250 TX or Emcephob HC in some overcoating sequences, and is used alongside Nafufill R3 FM where fine-filler levelling of the tunnel substrate is needed first — Space Arc can quote the full primer-plus-sealer package rather than the sealer in isolation. Where a project genuinely doesn’t need full tunnel-grade PU performance — for instance, general exposed RC surfaces on bridges, retaining walls or building facades needing anti-carbonation protection but not ÖBV/ASTRA/ZTV-ING tunnel certification or PU-level abrasion resistance — Fosroc’s Dekguard A Plus is a reasonable, more economical alternative in the same EN 1504-2 protective-coating family, though it is a water-based acrylic system and doesn’t carry the tunnel-specific abrasion, anti-skid or de-icing-salt performance built into MC-DUR 2496 CTP Tunnel. For genuine tunnel-lining work — highway tunnels, metro cut-and-cover, hydro headrace/tailrace linings — MC-DUR 2496 CTP Tunnel remains the more defensible spec on paper, and Space Arc’s role is to make sure the correct primer, filler and sealer combination reaches site together with batch documentation intact.
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