MC-Bauchemie Nafufill BJM Std
MC-Bauchemie’s ready-to-use, self-curing block joining mortar for AAC blocks, concrete blocks and fly ash bricks – thin 3mm joints, no water curing.
What is it?
A single-component, polymer modified cement mortar supplied as grey powder – mix with water and it’s ready to spread for jointing AAC and concrete blocks.
Where is it used?
AAC block, concrete block, hollow block and fly ash brick masonry walls – load-bearing and partition walls on residential, commercial and industrial sites across Delhi NCR and Pan-India.
Why use it?
Replaces the usual 10-12mm cement-sand joint with a 3mm bed, cutting mortar use and labour time, and its self-curing chemistry skips the daily water-curing masons otherwise have to do on every floor.
How is it applied?
Mixed mechanically at 400-500 rpm, spread evenly at 3mm over the block face, the next block placed and aligned while workable, vertical joints packed solid, then finished with a wooden or plastic float.
About MC-Bauchemie Nafufill BJM Std
Nafufill BJM Std is a single-component, polymer modified cement mortar that MC-Bauchemie markets specifically for jointing AAC blocks, solid and hollow concrete blocks, and fly ash bricks. Supplied as a grey powder in 30 kg bags, it is mixed with water on site and applied at a uniform 3mm bed thickness in place of the 10-12mm cement-sand mortar joints still common on Indian masonry sites. The logic behind thin-joint block mortars like this one is straightforward: AAC blocks are manufactured to tighter dimensional tolerances than country bricks, so a thick mortar bed is no longer needed to level out irregularities, and a thinner, factory-formulated mortar bonds the blocks together using far less material and less labour time per square metre of wall raised.
What makes it a practical fit for Delhi NCR sites is the self-curing claim on the manufacturer’s data sheet – once applied, the joint does not need the daily water-curing that ordinary cement-sand mortar demands, which matters on multi-storey AAC block jobs where curing dozens of partition walls by hand, floor after floor, is a genuine labour drag. Space Arc supplies Nafufill BJM Std to masonry contractors, AAC block dealers and site engineers working on residential towers, affordable housing and industrial shed partition walls, and we walk first-time users through the mandatory mechanical mixing step, because MC-Bauchemie is explicit on the TDS that hand mixing is not an acceptable substitute for this product – skip it and you risk an under-dispersed mix and patchy bond.
The technical insight
The chemistry behind Nafufill BJM Std is a polymer-modified hydraulic cement mortar – graded fine aggregates blended with a hydraulically setting binder and a polymer additive dosed in as a mineral admixture, delivered pre-blended so the only variable left on site is the water dose (7.8-9 litres per 30 kg bag, roughly 26-30% by weight). That polymer fraction is what does the two jobs the TDS advertises: it lowers the water demand needed to get workable consistency while still developing bond, and it forms a film within the curing matrix that slows moisture loss from the thin 3mm joint enough that separate water curing becomes unnecessary – useful because a 3mm bed has very little mass to hold onto curing water compared with a 10-12mm conventional joint, and would dry out fast without that polymer film. The >10 N/mm2 compressive strength and >0.7 N/mm2 tensile bond strength at 28 days are respectable for a jointing mortar rather than a structural repair mortar, and the non-shrink behaviour matters specifically because AAC blocks are dimensionally precise – any shrinkage in the joint would open hairline gaps along a wall face that’s meant to be nearly flush. The 400-500 rpm mechanical mixing requirement isn’t a formality either: at that speed the polymer particles disperse evenly through the water-cement paste, which hand mixing or a fast concrete mixer won’t reliably achieve, and an unevenly dispersed mix is the most common reason contractors see patchy bond strength across a wall.
Where it is used
- Thin-joint bedding mortar for AAC (autoclaved aerated concrete) block masonry walls
- Jointing solid and hollow concrete blocks in load-bearing and partition walls
- Fly ash brick masonry bedding mortar as a cement-sand mortar alternative
- Packing vertical joints between blocks for a solid, continuous wall face
- Partition wall construction inside RCC-framed residential and commercial towers
- Boundary and compound wall block-laying for factories, warehouses and plots
- Infill masonry for industrial sheds and warehouse partition walls
- Affordable and mass-housing projects where faster wall-raising and lower mortar consumption directly affect project cost
Key advantages
- Ready-to-use single-component formulation – only water needs to be added on site, no separate polymer or admixture dosing to get wrong
- Self-curing per the manufacturer’s data sheet – no daily water curing of joints required, which is a real saving on tall AAC block jobs
- Thin 3mm joint replaces the conventional 10-12mm cement-sand bed, cutting mortar consumption per square metre of wall
- Non-shrink with high bond strength – tensile bond strength of >0.7 N/mm2 and compressive strength of >10 N/mm2 at 28 days per the TDS
- Hand-applied with a trowel or float – masons already used to block-laying pick up the technique quickly
- Fast finishing time (60-90 minutes at 25C) keeps wall-raising moving without long waits between courses
- Factory-controlled polymer-modified mix is more consistent bag to bag than site-batched cement-sand mortar
- Works across AAC blocks, solid/hollow concrete blocks and fly ash bricks, so one product covers most block types used on a typical NCR site
Limitations & considerations
- It is a masonry block-jointing mortar, not a structural repair or crack-injection product – don’t specify it for spalled concrete or rebar corrosion repair
- TDS mandates mechanical mixing at 400-500 rpm and explicitly rules out hand mixing, so sites without a basic drill mixer will need to arrange one
- The 60-90 minute finishing time is quoted at 25C – in Delhi’s peak summer this window shortens, so batch sizes need to match what the crew can lay before the mortar stiffens
- Coverage of 3-4 kg/m2 assumes reasonably flat, dimensionally consistent blocks – warped or oversized AAC blocks will push consumption higher than the TDS figure
- Six-month shelf life from manufacture and sensitivity to rain, heat and direct sun during storage means bags can’t be stockpiled on site for long
- The manufacturer’s data sheet does not cite an IS, ASTM or EN standard reference for this product, so specification-driven projects should request third-party test certificates separately if compliance documentation is required
Selection & best practice
Do not treat this as a site-mixed cement-sand mortar you can eyeball. Pre-wet the blocks to SSD (saturated surface-dry) condition before laying – dry blocks pull water out of the mortar too fast and weaken the bond, while standing water on the surface is just as bad. Mix mechanically with a slow-speed drill at 400-500 rpm only; the TDS is explicit that hand mixing or a concrete mixer is not acceptable. Add two-thirds of the water first, add powder gradually while mixing for 3 minutes, then add the remaining water and mix a further 3 minutes, then let the mix stand for 5 minutes so the polymers disperse fully before use. Spread the mortar evenly at 3mm, place and align the next block while it is still workable, and pack every vertical joint solid – a common site shortcut is to butter only the horizontal bed and leave vertical joints loose, which defeats the non-shrink bond claim. In Delhi’s summer heat the 60-90 minute finishing window will run shorter than the 25C reference figure, so mix in batches sized to what the crew can actually place before it starts going off, and keep freshly laid joints out of direct sun and wind rather than assuming “self-curing” means “ignore it.”
Specifications
| Product Type | Polymer modified cement mortar |
| Form | Grey powder |
| Coverage | 3-4 kg/m2 at 3mm joint thickness |
| Mixing Water | 7.8-9 L (26-30%) per 30 kg bag |
| Bulk Density | ~1330 kg/m3 at 27C |
| Compressive Strength | >10 N/mm2 after 28 days |
| Tensile Strength | >0.7 N/mm2 after 28 days |
| Finishing Time | 60-90 minutes at 25C |
| Pack Size / Shelf Life | 30 kg bags; 6 months from manufacture, unopened |
Industry use cases
Residential high-rise (AAC block partitions)
Builders in Gurugram and Noida raising internal partition walls with AAC blocks use BJM Std to keep floor-wise wall-raising on schedule without a daily water-curing routine on every level.
Affordable and mass housing
Thinner joints and lower mortar consumption per square metre make a measurable dent in material cost across large-unit-count housing projects.
Industrial sheds and warehousing
Fly ash brick and hollow concrete block partition and boundary walls inside industrial and logistics facilities where fast wall-raising matters to handover timelines.
Commercial fit-outs
Office and retail interior partition walls built with concrete or AAC blocks where a clean, thin joint line and quick turnaround suit fit-out schedules.
Boundary and compound walls
Solid concrete block or brick compound walls for factories and plots, where non-shrink bond strength matters for long unsupported wall runs.
Frequently asked questions
Can Nafufill BJM Std be used to repair cracked or spalled concrete, or as a plaster?
Do the joints need to be water-cured like normal masonry mortar?
Can our masons mix it by hand like they mix cement-sand mortar?
How much coverage do I get from one 30 kg bag?
What’s the shelf life and how should we store it on site?
Is there a difference between Nafufill BJM and Nafufill BJM Std?
How we position MC-Bauchemie Nafufill BJM Std
Within MC-Bauchemie’s own India range, Nafufill BJM Std sits alongside the standard Nafufill BJM as one of two block-jointing mortar SKUs – both use the Nafufill name that MC-Bauchemie also applies to its broader concrete repair mortar family, so it’s worth being clear with clients that this specific product is formulated for masonry block-jointing, not for patching or resurfacing damaged concrete; if a site needs the latter, Space Arc can quote from MC’s dedicated repair mortar range separately. Against the market it actually competes in, Nafufill BJM Std’s real alternative on most Delhi NCR sites is conventional site-mixed cement-sand mortar at 10-12mm joint thickness, plus a handful of other branded thin-joint AAC block adhesives sold locally – the case for BJM Std over those is the documented bond and tensile strength data, self-curing claim, and MC-Bauchemie’s technical backup through Space Arc as an authorised applicator. We don’t currently carry a Fosroc equivalent for AAC block-jointing mortar specifically – Fosroc’s India range that we stock (Renderoc, Nitoflor, Conbextra, Nitoproof) is built around repair, flooring, grouting and waterproofing rather than masonry block-jointing, so there isn’t a genuine like-for-like Fosroc swap to offer here.
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