About MC-Bauchemie Nafufill BB 2

Nafufill BB2 is MC-Bauchemie’s acrylic bonding agent, sold in India through MC-Bauchemie (India) Pvt. Ltd., Navi Mumbai, and specified across the Nafufill repair range. It is a saponification-resistant acrylic co-polymer dispersion, not a mortar in its own right — it is gauged into cement, sand and other MC components to make bond coats, polymer-modified repair mortars, bonded screeds and waterproofing renders. Where an ordinary sand-cement patch simply sits on top of old concrete and eventually debonds, a BB2-modified system is designed to chemically and mechanically key into the substrate: MC’s own lab data on the modified mortar shows tensile adhesion climbing from 1.9 N/mm² at 7 days to 3.6 N/mm² at 90 days, with failure occurring in the parent concrete rather than at the bond line — which is the definition of a genuinely bonded repair rather than a cosmetic patch.

For Space Arc’s Delhi NCR and pan-India project base, BB2 earns its place on the truck for two practical reasons. First, a large share of repair work here is small-to-medium — spalled chajjas, leaking basement walls, honeycombed columns, cracked bridge soffits — where a full bagged PCC mortar is overkill and a site-mixed, BB2-modified mortar gets the same bond and flexibility at lower cost. Second, its “saponification-resistant” chemistry matters in India’s climate: cheaper PVA-based bonding agents can re-emulsify and lose strength when they stay damp for long periods (monsoon exposure, water tanks, basements), while BB2’s acrylic backbone is built to stay stable under sustained moisture — which is exactly the condition most repair and waterproofing sites see for months after application.

The technical insight

The property that actually distinguishes BB2 from a generic bonding agent is called out on the data sheet in one word: “saponification-resistant.” Many cheaper bonding agents are PVA (polyvinyl acetate) based, and PVA has a well-known failure mode — under sustained alkaline, damp conditions (exactly what a repaired basement wall, water tank or monsoon-exposed bridge soffit experiences for months), PVA can hydrolyse and re-emulsify, softening and losing bond strength long after the repair looked finished. BB2’s acrylic co-polymer backbone does not share that failure mode, which is why MC positions it for waterproofing mortars and as the polymer component of the Dichtament DS system, not just for dry interior patching. The other numbers on the sheet tell a consistent story: reducing the modulus of elasticity of the hardened mortar (more flexibility, less stress concentration at the bond line), improving water retention in the fresh mix (slower surface drying, fewer shrinkage cracks in thin layers), and plasticising the mix so a lower water-cement ratio is workable — all mechanisms that push in the same direction, toward a repair mortar that stays bonded and doesn’t crack away from the parent concrete over time, rather than one that merely tests strong on day one.

Where it is used

• Bond coat and gauging liquid for structural repair mortars on RCC columns, beams, slabs and bridge/flyover elements
• Polymer-modified bonded screeds and floor toppings laid over existing structural concrete
• Second component of the Dichtament DS waterproofing system, and general polymer modifier for waterproofing mortars on roofs, basements and water-retaining structures
• Bonding slurry (BB2 + cement mortar) for sealing cold joints between old and new concrete in staged pours
• Boosting the mechanical performance and bond of ready-to-use coarse and fine repair mortars used for general concrete repair
• Thin anti-carbonation and chloride-resisting protective coating overlays at the higher 10–12 kg per 50 kg cement dosage
• Repair mortar systems built in combination with Zentrifix AS spatter/rendering coat for larger-area vertical and overhead repairs
• Fine-filler repair systems built in combination with Nafuquick for smoother, thinner reinstatement layers

Key advantages

• Delivers a real structural bond, not a cosmetic patch — tensile adhesion rises to 3.6 N/mm² at 90 days with failures occurring in the parent concrete, per MC’s own reference-mix testing
• Saponification-resistant acrylic chemistry stays stable under sustained dampness, unlike cheaper PVA-based bonding agents that can re-emulsify in continuously wet conditions
• Reduces the modulus of elasticity of the hardened mortar, adding flexibility that absorbs movement at the old-to-new interface and cuts the risk of delamination
• Lifts both compressive (up to 55 N/mm² at 28 days) and flexural (11.0 N/mm² at 28 days) strength of the modified mortar over an unmodified reference mix
• Cuts water absorption of the hardened mortar, giving a meaningful waterproofing boost — useful on its own and essential as the second component of the Dichtament DS system
• Plasticises the fresh mix so a lower water-cement ratio can be used at workable consistency, which in turn reduces shrinkage cracking
• Improves water retention in the fresh mortar, slowing surface drying and reducing the drying-shrinkage cracks that plague thin repair layers and screeds
• Sold in workable 5 kg and 30 kg packs, so it scales from a single balcony repair to a multi-tonne bridge rehabilitation job without wastage

Limitations & considerations

• It is an additive, not a mortar — always has to be gauged with cement/sand or with MC’s own repair-mortar components, adding a mixing step and a dosage decision to every batch
• Bond quality depends on wet-on-wet placement; if the bond coat is allowed to dry or skin over before the repair mortar goes on, the tested adhesion values will not be achieved
• The higher 10–12 kg/50 kg cement dosage is for thin anti-carbonation/chloride-resisting coatings only — it is not meant for thick mortar sections
• Requires a sound substrate with minimum 1.5 N/mm² pull-off tensile strength, so weak, oil-contaminated or carbonated cover concrete must be cut back first, adding to prep scope
• Shelf life is limited to 9 months from manufacture and the product must be protected from rain, direct sun, heat and frost in storage — poor stock rotation on site can waste material
• The India data sheet does not carry specific IS/BS/EN third-party certification numbers, so specifiers who need a particular code citation should confirm directly with MC-Bauchemie

Selection & best practice

Specifications

Industry use cases

How we position MC-Bauchemie Nafufill BB 2

Within MC-Bauchemie’s own India range, BB2 is the bonding-agent/polymer-modifier building block behind several named systems rather than a competitor to them: it is used with Zentrifix AS as a spatter/rendering coat system for larger repairs, with Nafuquick as a fine-filler mortar system for thinner reinstatement, and as the stated second component of the Dichtament DS waterproofing system — so a Space Arc BOQ that specifies Dichtament DS, Zentrifix AS or Nafuquick should generally carry BB2 alongside it, not instead of it. It also sits under MC’s broader Nafufill banner of concrete repair products sold in India, which specifiers commonly pair it with for bagged repair mortars needing an extra bond/flexibility boost. Outside the MC range, the closest genuine equivalent is Fosroc’s Nitobond AR, an acrylic-polymer bonding aid and gauging liquid with its own published bond-strength (BS 6319) and coverage data; where a contractor is already standardised on Fosroc systems or wants that specific documentation, Nitobond AR is a credible alternative, while Fosroc’s SBR-based Nitobond SBR covers the same functional role with a different (styrene-butadiene rubber) polymer backbone for teams that prefer that chemistry.

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