MC-Bauchemie Nafufill KM 230
Fibre-reinforced, EN 1504-3 Class R3 concrete replacement mortar for structural repair — hand-trowelled or wet-sprayed, engineered by MC-Bauchemie.
What is it?
A one-component, fibre-reinforced, polymer-modified cementitious (PCC) concrete replacement mortar, classified EN 1504-3 Class R3, for hand or wet-spray structural repair.
Where is it used?
RCC columns, beams, slabs, retaining walls, water/hydraulic structures, bridges, parking structures and coastal RCC elements — vertical and overhead surfaces.
Why use it?
Restores load-bearing concrete section with high compressive/flexural strength, low shrinkage and an E-modulus close to parent concrete, resisting carbonation, frost/de-icing-type attack and chloride ingress.
How is it applied?
Mixed 100:18-19 (powder:water by weight) in a forced-action mixer, bonded onto a Nafufill KMH/BC primer coat, then hand-trowelled or wet-sprayed in 6-30 mm passes up to 60 mm total (100 mm as a reprofiling mortar), cured under cover for 3 days.
About MC-Bauchemie Nafufill KM 230
Reinforced concrete across Delhi NCR and India’s coastal belt takes a beating from carbonation, chloride ingress and plain neglect — spalled cover concrete, corroding rebar and cracked soffits are among the most common repair calls on site. Nafufill KM 230 is MC-Bauchemie’s answer for exactly this kind of statically relevant damage: a one-component, polymer-modified, fibre-reinforced cementitious mortar built to EN 1504-3 Class R3, meant to replace lost concrete section and restore load-transfer capacity rather than just patch the cosmetic surface.
It isn’t a standalone product so much as the workhorse of a repair system — substrate preparation, a Nafufill KMH or Nafufill BC bonding/corrosion-protection coat on the primed rebar and concrete, then KM 230 built up in layers by hand-trowel or wet-spray. MC-Bauchemie rates it differently depending on how it goes on, since spray-applied mortar compacts denser and tests stronger than hand-applied. On Indian sites, that means the method statement and crew training matter as much as the bag itself.
The technical insight
The two figures worth pulling from the data sheet are E-modulus and shrinkage. Hand-applied KM 230 sits at 16,600 N/mm² and spray-applied at 22,600 N/mm² after 28 days — close enough to typical M25-M35 parent concrete that the patch deforms with the substrate instead of against it, which is what actually prevents edge-cracking over a few monsoon cycles. Shrinkage is a modest 0.8 mm/m at 28 days, and carbonation resistance is rated at 1.7 mm ingress or less after 90 days — figures consistent with a mortar meant to sit exposed on a column face for decades. The 2 mm maximum grain size keeps it fine enough for feather-edging and overhead work, while the layer-thickness range (6-30 mm per pass, 60 mm total, 100 mm as a reprofiling mortar) signals a build-up system, not a substitute for formwork-poured concrete.
Where it is used
- Spalled RCC column, beam and shear-wall repair
- Overhead repair of slab soffits, balconies and chajjas
- Retaining walls and hydraulic structures, SRM repair per ZTV-W LB 219
- Bridge pier, abutment and pier-cap restoration by wet-spray
- Cover-concrete reinstatement after Nafufill KMH corrosion protection
- Parking-structure columns and slabs exposed to vehicle-tracked chloride
- Coastal and marine RCC jetties/piers under XS/WA exposure classes
- Parapets, copings and other statically relevant precast elements
Key advantages
- Single-component, factory-controlled — no on-site mix-ratio guesswork
- Fibre reinforcement lifts flexural strength and crack/impact resistance
- Dual hand/spray route covers small patches and large jobs with one product
- Strong 28-day figures both ways: 35 N/mm² (hand), 45 N/mm² (spray) compressive
- Low 0.8 mm/m shrinkage cuts debonding risk versus cheaper repair mortars
- E-modulus close to parent concrete avoids a stress-concentration patch
- EN 13501-1 Class A1 non-combustible, suited to occupied/fire-rated structures
- Certified across XC, XF, XD, XS and WA/WF/WO exposure classes
Limitations & considerations
- Needs a Nafufill KMH/BC bonding coat first — cannot go direct onto bare, oiled or laitance-covered concrete
- Working time falls from 45 min at 20°C to about 30 min at 30°C — a real constraint in Delhi summers
- 2 mm max grain size and 100 mm reprofiling ceiling rule out large-volume section recasting
- Forced-action or slow double mixer only — hand-mixing and part-bag mixing are disallowed
- Needs 3 days’ cure protection from sun/wind, or surface crazing follows in hot, dry weather
- India’s MC-Bauchemie catalogue lists the comparable mortar as Nafufill KM 250-IN — confirm exact SKU with Space Arc
Selection & best practice
Never skip the bond coat — Nafufill KMH (which doubles as rebar corrosion protection) or Nafufill BC goes on first, per MC-Bauchemie’s General Application Advice for concrete replacement systems. Mix only in a forced-action or slow double mixer at 100:18-19 powder-to-water by weight (roughly 4.5-4.75 litres per 25 kg bag); hand-mixing shows up later as weak, inconsistent patches. Treat the working-time figures as real deadlines in summer heat, batch small, build up in 6-30 mm passes rather than one thick slather, and shield the finished surface from sun and wind for the full 3-day cure.
Specifications
| Chemistry / system | One-component, fibre-reinforced, polymer-modified PCC (Portland cement concrete) repair mortar |
| Standard classification | EN 1504-3, Class R3 (principles 3, 4, 7; procedures 3.1, 3.3, 4.4, 7.1, 7.2, 7.4) |
| Maximum grain size | 2 mm |
| Mixing ratio | 100 : 18-19 by weight (powder : water); ~4.5-4.75 L water per 25 kg bag |
| Compressive strength, 28 d | ≥35 N/mm² hand-applied; ≥45 N/mm² spray-applied |
| Flexural strength, 28 d | ≥5 N/mm² hand-applied; ≥6 N/mm² spray-applied |
| Pull-off (bond) strength | ≥2.1 N/mm² |
| Layer thickness | 6-30 mm per pass, 60 mm max total, up to 100 mm as a reprofiling mortar |
| Pack size | 25 kg bag, cement-grey powder |
Industry use cases
Industrial / manufacturing
Chloride- and carbonation-damaged RCC columns and beams in process plants, without shuttered-recasting downtime
Infrastructure / bridges
Pier, abutment and pier-cap spalling repair, wet-sprayed to cut shuttering time on live structures
Water / hydraulic structures
Canal, reservoir and retaining-wall repair specified as SRM per ZTV-W LB 219
Residential / commercial buildings
Balcony soffits, chajjas and cantilevered projections needing overhead-rated repair
Multi-storey car parks
Column and slab restoration where vehicle-tracked chloride mimics de-icing-salt exposure
Frequently asked questions
Is Nafufill KM 230 the exact product MC-Bauchemie sells in India?
Can this be applied overhead, on a slab soffit or balcony underside?
Why does the data sheet give two different strength values for the same product?
Do I need a separate primer before applying KM 230?
How much material do I need per square metre of repair?
How long does the mortar stay workable once mixed, in Indian conditions?
How we position MC-Bauchemie Nafufill KM 230
KM 230 sits in MC-Bauchemie’s Nafufill repair-mortar family alongside the finer levelling mortar Nafufill KM 110, the lighter fibre-reinforced Nafufill KM 220, and the higher-build Nafufill KM 250 — pair any of them with Nafufill KMH for rebar corrosion protection and bonding, and follow through with an MC-DUR or Emcephob-range coating where exposure continues after the patch cures. MC-Bauchemie’s India catalogue markets the comparable local product as Nafufill KM 250-IN, so confirm exact SKU and supply route with Space Arc before finalising a BOQ. Where a project is already standardised on Fosroc systems, Renderoc HB40 is a genuinely comparable fibre-reinforced, formwork-free repair mortar worth shortlisting alongside KM 230.
Fosroc Renderoc HB40 — A specifier or contractor already standardised on Fosroc systems, or wanting a high-build (up to 40 mm vertical/30 mm overhead) formwork-free repair mortar without sourcing an EU-spec import, might choose Renderoc HB40 over Nafufill KM 230.
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