MC-Bauchemie Nafufill FM Micro-Concrete
A flowable, single-component micro-concrete from MC-Bauchemie’s Nafufill range, engineered to reinstate load-bearing sections at EN 1504-3 Class R4 without downgrading the structure.
What is it?
A factory-blended, polymer-modified micro-concrete from MC-Bauchemie’s Nafufill family, gauged with water on site to a fluid, self-levelling consistency for structural concrete replacement.
Where is it used?
Deep-section repairs on columns, bridge piers, beams and other reinforced-concrete members where reinforcement is congested and hand-packed mortar cannot reach.
Why use it?
It delivers Class R4 structural performance — around 60 N/mm2 compressive strength at 28 days — so the repaired zone carries full design load without a strength penalty.
How is it applied?
Poured or pumped into formwork enclosing the prepared, saturated repair void; it flows around bars and self-consolidates, needing little or no vibration.
About MC-Bauchemie Nafufill FM Micro-Concrete
MC-Bauchemie’s Nafufill FM belongs to the German manufacturer’s Nafufill concrete-replacement portfolio, a family that has been repairing bridges, tunnels, dams and industrial structures across Europe and India for decades. Unlike a trowel-applied patch mortar, the FM grade is a flowable micro-concrete: a single-component powder, factory-blended with graded fine aggregate, cement and modifying polymers, that is simply mixed with clean water on site until it reaches a pourable consistency. That fluidity is the whole point. When a column or pier has lost a large slab of cover and the exposed reinforcement sits in a dense cage, you cannot reliably hand-pack a stiff mortar into every void. A flowable micro-concrete is poured or pumped into formwork and finds its own way around the bars, filling the section completely.
For a distributor-applicator working across Delhi NCR and the rest of India, the appeal is repeatability. Because every 25 kg bag carries the same factory recipe, the site crew is not batching sand, cement and admixture by eye — they add a measured quantity of water and get a consistent result pour after pour. The cured material is classified Class R4 to EN 1504-3, the highest structural-repair grade, which means a consulting engineer can specify it to reinstate a member to its original design capacity rather than accepting a reduced load rating. Space Arc Engineering supplies Nafufill FM, advises on section design and formwork, and can undertake the application itself on rehabilitation contracts.
The technical insight
The performance of a flowable micro-concrete rests on a deliberate compromise between two things that usually fight each other: high flow and high strength. Ordinary concrete becomes fluid only if you add a lot of water, and that extra water is what wrecks strength and drives shrinkage cracking. Nafufill FM sidesteps this by using a tightly graded fine aggregate (maximum grain size under about 2 mm) together with polymer modification and a water-reducing chemistry, so the mix flows freely at a low water content of roughly 15-16% by weight of powder. The dense, well-graded matrix that results develops around 60 N/mm2 compressive strength and near 19 N/mm2 flexural strength at 28 days, with a fresh density of 2.0-2.1 kg/dm3 that reflects how little air and excess water it carries. Just as important as raw strength is the bond to the parent concrete — a repair is only as good as the interface — and the material reaches a slant-shear bond above 20 N/mm2 and pull-off adhesion above 1.5 N/mm2, values high enough that failure occurs in the substrate rather than at the joint. Low water absorption (under 2.5%) and low chloride permeability give the repaired zone durability comparable to sound structural concrete.
Where it is used
- Jacketing and re-sectioning of reinforced-concrete columns that have lost cover to corrosion or overload
- Repair of bridge piers, pier caps and abutments in highway and railway structures
- Full-depth reinstatement of beam soffits and haunches where reinforcement is heavily congested
- Restoration of load-bearing sections in car parks, silos and industrial frames
- Encasement of newly exposed and cleaned reinforcement after concrete removal
- Filling of precast beam-to-column connections and grout pockets requiring structural continuity
- Rehabilitation of water-retaining and marine structures exposed to chlorides and de-icing salts
- Deep patch repairs where formwork can be erected but a stiff hand-applied mortar cannot be compacted
Key advantages
- Class R4 to EN 1504-3, the highest structural-repair grade, so members can be reinstated to full design capacity
- Flowable consistency reaches congested reinforcement and deep voids that trowel-applied mortars miss
- Single-component and factory-blended — only clean water is added, removing site batching error
- Self-consolidating placement needs little or no vibration, cutting labour and honeycombing risk
- High early and 28-day strength (around 60 N/mm2) lets structures return to service on a predictable schedule
- Strong bond to sound concrete (slant-shear above 20 N/mm2) that keeps failure in the substrate, not the interface
- Low permeability and chloride resistance protect the reinstated reinforcement long-term
- Backed by MC-Bauchemie’s documented Nafufill test data and Space Arc’s local supply and applicator support
Limitations & considerations
- Needs formwork and a pour or pump route — it is not a hand-applied patch material for thin or overhead spot repairs
- Effective only after correct surface preparation: reinforcement cleaned to bright metal and the substrate saturated surface-dry
- Adding water beyond the stated 15-16% to make it flow easier will lower strength and increase shrinkage
- Fresh work must be protected and cured against rapid drying, wind and direct sun, especially in Indian summer conditions
- Not intended as a cosmetic finishing or fairing mortar — a fine repair mortar is used for the final surface
- Very large single pours generate heat and demand attention to lift heights and pour sequencing
Selection & best practice
Success with a flowable micro-concrete is decided before the first bag is opened. Break out all loose and carbonated concrete back to a sound, roughened substrate, then clean the exposed reinforcement to bright metal and treat it with a compatible zinc-rich or cementitious primer where the design calls for it. Saturate the parent concrete to a saturated surface-dry condition so it does not draw water out of the fresh mix. Build tight, well-braced formwork with a pour or pump point and provision for air to escape, and gauge each 25 kg bag with only the recommended 3.75-4.00 litres of clean water, mixing mechanically to a lump-free, flowing consistency — never mix by hand and never over-water to chase flow. Place continuously to avoid cold joints, pouring from one side so the material displaces air as it advances. Once cast, cure diligently with wet hessian, ponding or a curing membrane for at least the first few days to develop full strength and control shrinkage.
Specifications
| Product type | Single-component, polymer-modified flowable micro-concrete |
| Standard / class | EN 1504-3 Class R4 (structural repair) |
| Compressive strength (28 days) | ~60 N/mm2 |
| Flexural strength (28 days) | ~19 N/mm2 |
| Bond / slant-shear strength | >20 N/mm2 (pull-off >1.5 N/mm2) |
| Maximum grain size | <2.0 mm |
| Fresh mortar density | 2.0-2.1 kg/dm3 |
| Water demand | ~15-16% by weight (3.75-4.00 L per 25 kg bag) |
| Pack size | 25 kg bag |
Industry use cases
Bridges & Highways
Reinstating spalled pier caps and columns on road and rail bridges to full section, restoring load capacity without a permanent traffic downgrade.
Water & Marine
Repairing chloride-attacked members in tanks, treatment plants and coastal structures, where low permeability keeps the reinstated rebar protected.
Industrial & Power
Re-sectioning load-bearing columns and beams in plants, silos and cooling structures during shutdown windows that demand fast, reliable strength gain.
Commercial & Parking
Deep repairs to car-park decks and framed buildings where corroded reinforcement in congested zones rules out hand-packed mortars.
Heritage & Rehabilitation
Structural strengthening of ageing RCC frames as part of a wider EN 1504 rehabilitation scheme, poured into formwork around retained reinforcement.
Frequently asked questions
Is Nafufill FM a repair mortar or a micro-concrete?
What compressive strength does it reach?
How much water do I add per bag?
What section thickness and depth can it handle?
Does the concrete surface need special preparation?
Can Space Arc supply and apply it across India?
How we position MC-Bauchemie Nafufill FM Micro-Concrete
Within MC-Bauchemie’s own range, Nafufill FM sits alongside the Nafufill KM 250 concrete-replacement grade, which is a hand and wet-spray applied R4 mortar for shallower sections — choose KM 250 where formwork is impractical and the repair depth is modest, and FM where you need a flowable pour into congested, deep formwork. Pair the repair with an MC-Bauchemie bonding coat and a compatible reinforcement primer for a single-source EN 1504 system, and finish exposed faces with a fine Nafufill fairing mortar. Where a project standardises on another supplier, Space Arc also stocks equivalent flowable micro-concretes from Fosroc, and can cross-specify Sika and Dr. Fixit repair systems to match an existing approved-vendor list.
Fosroc Renderoc LA55 — Specify the Fosroc option when the project’s approved-vendor list or an existing Fosroc repair system already governs the site, since Renderoc LA55 is a directly equivalent free-flowing, low-alkali R4 micro-concrete for form-and-pour reinstatement.
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