MC-Bauchemie Nafufill KM 250DS-IN
A one-component, fibre-reinforced R4 structural repair mortar with dual shrinkage compensation, engineered for tunnels, bridges and load-bearing RCC repairs across India.
What is it?
A single-component, fibre-reinforced polymer cement concrete (PCC) repair mortar with dual shrinkage compensation, classified R4 under EN 1504-3 for structural, load-bearing concrete reinstatement.
Where is it used?
Tunnel linings, bridge piers and decks, dock yards, water-retaining structures, and RCC columns, beams and slabs in industrial and high-rise buildings, wherever corrosion or spalling has compromised structural concrete.
Why use it?
Reaches 55 N/mm² compressive strength at 28 days, shows zero measured carbonation depth after 90 days, and resists chlorides and de-icing salts, so the repair itself doesn’t become the next failure point.
How is it applied?
Mixed with water in a forced-action mixer, hand-applied over a bonding coat or wet-sprayed onto a saturated-surface-dry substrate with cleaned, de-rusted reinforcement, then finished with a float or sponge squeegee and cured for 3 days.
About MC-Bauchemie Nafufill KM 250DS-IN
Spalled concrete on a load-bearing column or a tunnel lining is not a cosmetic problem, it is a structural one, and treating it like a cosmetic patch is how repairs fail a second time. Nafufill KM 250DS-IN is MC-Bauchemie’s India-market structural repair mortar, built for that harder job: reinstating concrete that still has to carry load, across the PCC and SPCC sections that Indian drawings and specifications refer to. It is a one-component, fibre-reinforced polymer cement concrete supplied as a grey powder in 30 kg sacks, ready to mix and trowel or spray once water is added.
What sets it apart from a generic patch mortar is the “DS” in its name: dual shrinkage compensation, built into the single-component mix so it resists both the early plastic shrinkage that shows up as surface crazing and the later drying shrinkage that opens hairline cracks at the patch edge, usually the first sign a repair is about to delaminate. Rated Class R4 under EN 1504-3, the standard’s highest structural class, and tested locally to ASTM C-109, it reaches 30 N/mm² in 48 hours and 55 N/mm² at 28 days, is chloride-proof, and records zero carbonation depth after 90 days, numbers that matter on a bridge pier or tunnel lining, not a garden wall.
The technical insight
MC-Bauchemie tests Nafufill KM 250DS-IN to ASTM C-109 rather than the EN cube methods used on its European Nafufill KM 250 sibling, a deliberate India-market adaptation, since Indian consultants and labs are set up around ASTM and IS testing regimes. The performance class carries over: R4 under EN 1504-3, the same top tier MC uses for structural tunnel and bridge repairs globally. The fibre reinforcement is functional, not cosmetic: short fibres bridge the micro-cracks that shrinkage compensation alone does not fully eliminate, which is what keeps a 50-80 mm thick structural patch from cracking along its own edge as it cures. Because the product is also certified as a repair and anode-embedding mortar under EN 12696, it is compatible with impressed-current cathodic protection retrofits, a detail that matters increasingly on Indian metro and coastal infrastructure projects moving from one-time patching toward active corrosion management.
Where it is used
- Structural reinstatement of spalled or corroded RCC columns, beams and slabs
- Tunnel lining and segment repair on metro and road tunnel projects
- Bridge pier, pier-cap and deck-soffit restoration in coastal exposure zones
- Dock yard, jetty and marine structure concrete repair
- Water-retaining structures — STP/WTP tanks, canal and reservoir linings
- Anode-embedding mortar for EN 12696 cathodic-protection retrofits
- Reprofiling of chipped, broken or spalled concrete after rebar de-rusting
- Vertical and overhead structural repair by hand trowel or wet-spray
Key advantages
- One-component — just add water, no separate polymer or liquid to dose on site
- Dual shrinkage compensation cuts micro-cracking and edge-of-patch delamination risk
- Fibre reinforcement bridges micro-cracks and improves impact resistance over plain mortars
- R4-class 55 N/mm² strength suits genuine structural, load-bearing repair, not just patching
- Zero measured carbonation depth after 90 days helps protect embedded reinforcement
- Chloride-proof and de-icing-salt resistant, suited to coastal and industrial exposure
- Applies by hand or wet-spray, giving flexibility on access-constrained sites
- Compatible with MC’s own bonding coats and corrosion-protection primers for a matched system
Limitations & considerations
- Minimum 10 mm layer thickness per coat — not a substitute for thin cosmetic skim coats
- Application limited to 5-35°C air/substrate temperature and needs a saturated-surface-dry substrate
- Requires a forced-action or slow-speed paddle mixer; hand-mixing is not permitted per the datasheet
- Grey powder finish may need cosmetic top-coating to match exposed architectural concrete
- 9-month shelf life, and bags must be kept dry, cool and away from direct sun and frost
- Full 28-day cure is needed for rated strength, so structural reinstatement timelines must allow for it
Selection & best practice
Treat surface preparation as the real determinant of success. The substrate must be sound, contaminant-free and saturated-surface-dry before the mortar goes on, and any corroded reinforcement has to be fully de-rusted to blasting grade SA2 per EN ISO 12944 before it is covered. For hand application, always prime with Nafufill KMH or an MC Solid Range bonding agent; skipping the bond coat is the single most common cause of debonded patches on site. Mix for a minimum of 5 minutes in a forced-action or slow-speed paddle mixer, never by hand, and protect the finished repair from sun, wind and rapid drying through the full 3-day curing period.
Specifications
| Compressive strength (ASTM C-109, 50 mm cube, PCC) | 30 N/mm² @ 48 hrs · 42 N/mm² @ 7 days · 55 N/mm² @ 28 days |
| Flexural strength | >5 N/mm² @ 28 days |
| Tensile strength | >1.5 N/mm² @ 28 days |
| Carbonation depth | 0 mm after 90 days |
| Fresh mortar density (PCC) | 2,090 kg/m³ |
| Layer thickness | 10 mm min – 25 mm max per coat; 50 mm max total; up to 80 mm for reprofiling |
| Mixing water | 4.5–5.1 L (15–17%) per 30 kg bag |
| Standard / classification | EN 1504-3 Class R4; EN 12696 repair & anode-embedding mortar |
| Pack size & shelf life | 30 kg sacks; 9 months from manufacture, unopened |
Industry use cases
Metro & road tunnels
Structural relining of tunnel segments and linings under dynamic loading, where R4 strength and EN 12696 compatibility support cathodic-protection retrofits.
Bridges & flyovers
Restoration of corrosion-damaged piers, pier caps and deck soffits in coastal or industrial exposure zones where chloride ingress has attacked the rebar.
Industrial & process plants
Reinstatement of spalled RCC columns, beams and foundations in chemical, cement and power-plant structures exposed to carbonation.
Ports & water-retaining structures
Repair of dock yards, jetties, STP/WTP tanks and canal linings where the mortar must resist sustained wetting, chlorides and dynamic loads.
High-rise & residential RCC repair
Structural reinstatement of corroded balconies, columns and beams in ageing residential and commercial towers across Delhi NCR.
Frequently asked questions
Is Nafufill KM 250DS-IN meant for structural repairs or just cosmetic patching?
What does “dual shrinkage compensation” actually mean?
Do I need a separate bonding coat?
How much material do I need per square metre?
What prep does the reinforcement need before applying this mortar?
How does this compare to Fosroc’s equivalent product?
How we position MC-Bauchemie Nafufill KM 250DS-IN
Nafufill KM 250DS-IN sits at the structural, heavy-duty end of MC-Bauchemie’s Indian Nafufill repair range. For general-purpose patching that doesn’t carry structural load, Space Arc also stocks MC-Nafufill N, a slower-setting, lower-strength (20-25 MPa) cementitious mortar built for unhurried finishing rather than load-bearing reinstatement; use KM 250DS-IN when the repair is structural and Nafufill N when it isn’t. Pair it with Nafufill KMH, or an MC Solid Range bonding agent, as specified on the datasheet, and with MC’s corrosion-protection primers wherever reinforcement has been de-rusted. Outside the MC-Bauchemie stable, the nearest genuine equivalent is Fosroc’s Renderoc HS Xtra, a comparably fibre-reinforced, shrinkage-controlled structural mortar; specifiers already standardised on Fosroc, or chasing a higher strength grade, may prefer it, while Space Arc can supply and apply either brand depending on the project specification.
Fosroc Renderoc HS Xtra — A specifier already standardised on Fosroc’s Renderoc range, or chasing a higher 28-day strength figure (over 70 N/mm² versus Nafufill’s 55 N/mm²), might choose Renderoc HS Xtra instead.
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