Fosroc Nitobond Betonklæber
Fosroc’s polymer-emulsion concrete bonding agent — the “betonklæber” that locks fresh repair mortar to old concrete for a durable, monolithic bond.
What is it?
A single-component polymer (acrylic/SBR) emulsion bonding agent from Fosroc’s Nitobond range. ‘Betonklæber’ is the Danish-market name meaning ‘concrete adhesive’ — it is the brush- or slurry-applied bond coat that joins new cementitious mortar or concrete to a prepared existing surface.
Where is it used?
Concrete repair and rehabilitation: bonding repair mortars, screeds, renders and toppings to old concrete or masonry on bridges, water tanks, basements, columns, beams, floors and facades.
Why use it?
Old concrete is dense and low-suction; fresh mortar placed straight onto it tends to delaminate. The bonding agent dramatically improves adhesion, reduces shrinkage cracking and lets thinner, more economical repair sections be placed.
How is it applied?
Surface is cleaned and saturated-surface-dry; the emulsion is brushed neat as a bond coat or gauged into a cement slurry, and the repair mortar is worked wet-on-wet into the still-tacky coat before it skins over.
About Fosroc Nitobond Betonklæber
Fosroc Nitobond Betonklæber is the Danish-market presentation of Fosroc’s well-established Nitobond family of polymer concrete bonding agents. The word “betonklæber” is simply Danish for “concrete adhesive,” and on Fosroc’s Denmark site it sits within the Adhesives / Betonklæber solutions category alongside the global Nitobond brand. In practical engineering terms it is the same class of product that Indian contractors know as Nitobond — a liquid polymer emulsion, supplied ready to use, that is applied as a thin bond coat between a hardened, prepared substrate and a fresh layer of cementitious mortar or concrete.
The problem it solves is a classic one in repair work. When a patch repair, screed or render is placed directly onto mature, dense concrete, the two materials behave like strangers: the old surface barely absorbs the fresh paste, plastic shrinkage pulls the new layer away at the interface, and within months the repair drums, cracks at the perimeter and eventually spalls off. A bonding agent re-establishes a continuous mechanical and chemical link across that cold joint. Used as a brush-applied primer it wets out the substrate and stays tacky long enough for the repair mortar to be compacted into it; gauged into a cement slurry it forms a high-grip scrub coat; and blended into the mortar itself (the SBR route) it modifies the matrix to improve adhesion, tensile and flexural behaviour and water resistance.
Within Fosroc’s system the bonding agent is rarely a stand-alone product — it is the primer step of a complete concrete-repair sequence that runs from corrosion-protection priming of exposed steel, through the bond coat, to the placement of a Renderoc-type repair mortar and a final protective coating. For Space Arc’s customers in Delhi NCR and across India, this is the everyday workhorse behind sound, long-lasting patch repairs on RCC structures exposed to monsoon wetting-drying, carbonation and chloride attack.
The technical insight
Bonding agents in the Nitobond range divide by chemistry, and choosing correctly is the whole game. The acrylic-emulsion grades (Nitobond AR / ST class) are single-component, ready-to-use, re-emulsifiable bond coats and curing aids — quick and forgiving, ideal as a brush primer and gauging liquid, but because acrylics can soften under prolonged water contact they are best kept to internal or intermittently-wet locations. The styrene-butadiene-rubber (SBR) grade is a water-resistant polymer additive: in Fosroc’s verified test data a 3:1 sand:cement mortar gauged at 4 litres SBR per 20 kg cement reached roughly 62 MPa compressive, 3.3 MPa tensile, 9 MPa flexural and a slant-shear bond of about 53 MPa (BS 6319), with a VOC content of 29 g/litre — numbers that explain why SBR is preferred for water-retaining and externally-exposed repairs. Where the substrate is permanently damp or the bond must be structural and chemically aggressive, Fosroc directs users to the two-part epoxy bonding aid (Nitobond EP) instead. The practical rule on site is the open time, not the spec sheet: the repair mortar must go in while the bond coat is still tacky. If the coat dries and skins, it must be re-coated — placing mortar onto a dried film gives you a debonding plane, not a bond.
Where it is used
- Bonding fresh concrete-repair mortars and patch repairs to prepared old concrete on columns, beams and slabs
- Scratch-coat / slurry-primer bond coat ahead of Renderoc-type repair mortars and hand-applied renders
- Bonding cementitious screeds and toppings to existing concrete floors to prevent delamination
- Repairs to water-retaining structures, tanks and basements (SBR grade for water resistance)
- Bonding new-to-old concrete at construction joints and structural repair interfaces
- As a gauging/modifying liquid blended into site-batched mortars to improve adhesion and reduce shrinkage
- Curing aid and adhesion improver for thin-section cementitious repairs
Key advantages
- Greatly improves adhesion of new cementitious material to dense, low-suction old concrete
- Reduces interface shrinkage cracking and the risk of patch repairs drumming or spalling
- Single-component and ready to use (emulsion grades) — minimal site mixing, low wastage
- Enables thinner, more economical repair sections than unbonded mortar would allow
- SBR grade adds water resistance plus improved tensile and flexural performance to the repair mortar
- Improves bond, tensile and flexural properties of site-batched mortars when used as a gauging liquid
- Part of a complete, compatible Fosroc repair system (primer, bond coat, mortar, coating)
- Brush, roller or scrub-coat application suits irregular and overhead repair geometries
Limitations & considerations
- Bond coat has a limited open time — mortar must be placed while it is still tacky, or the area must be re-coated
- Acrylic-emulsion grades are not ideal for permanently wet or submerged surfaces; use the SBR or epoxy grade there
- Not a structural adhesive on its own — for permanently damp or high-stress structural bonds Fosroc recommends the two-part epoxy (Nitobond EP)
- Performance depends entirely on substrate preparation: all unsound concrete, laitance, dust, oil and curing compounds must be removed first
- Emulsion grades should be protected from frost in storage and not applied at low temperatures (around 5°C and falling)
- No standalone Danish technical data sheet for the ‘Betonklæber’ name — specifying engineers should reference the specific Nitobond grade (AR/ST, SBR or EP) and its TDS
- Coverage is substrate-dependent; rough or porous surfaces consume more material than theoretical figures suggest
Selection & best practice
Treat preparation as 80% of the job. Break out all unsound and delaminated concrete back to a sound, roughened substrate, expose and clean any corroded reinforcement and prime the steel before bonding. Remove laitance, dust, oil and old curing membranes by grit-blasting or mechanical scabbling, then bring the surface to saturated-surface-dry — damp but with no standing water. Match the grade to the exposure: acrylic (AR/ST) for internal or intermittently-wet patch repairs and as a gauging liquid, SBR for water-retaining and externally-exposed work, and the two-part epoxy (Nitobond EP) where the substrate is permanently damp or the bond must be structural. Apply the bond coat by stiff brush or scrub it well into the surface as a slurry, and place the repair mortar wet-on-wet before the coat skins over — if it dries, re-coat rather than placing onto a dead film. In Indian summer conditions work in the shade, use cool mixing water and protect the repair, then cure the cementitious repair immediately and thoroughly to develop strength and limit shrinkage at the new interface.
Specifications
| Product type | Polymer-emulsion concrete bonding agent (Nitobond range; ‘Betonklæber’ = Danish for concrete adhesive) |
| Available chemistries | Acrylic emulsion (AR/ST class), SBR emulsion, and two-part epoxy (EP) variants |
| Acrylic/SBR grade form | Single-component, ready-to-use white liquid emulsion |
| SBR grade chemistry | Modified styrene-butadiene rubber emulsion |
| SBR mortar compressive strength | ~62 MPa (3:1 sand:cement, 4 L SBR per 20 kg cement, BS 6319) |
| SBR mortar tensile strength | ~3.3 MPa (BS 6319) |
| SBR mortar flexural strength | ~9 MPa (BS 6319) |
| SBR mortar slant shear bond | ~53 MPa (BS 6319) |
| SBR VOC content | 29 g/litre |
| Typical SBR mortar thickness | 6 mm to 40 mm per application |
| Application method | Brush / scrub-coat bond coat, or gauged into cement slurry / mortar |
| Substrate condition | Sound, clean, saturated-surface-dry (SSD) |
| Damp/structural substrate | Use two-part epoxy bonding aid (Nitobond EP) instead |
| Cleaning | Tools cleaned with water immediately; cured material removed mechanically |
| Storage | Cool, dry store; protect emulsion grades from frost |
Industry use cases
Bridge & infrastructure repair
Bond coat for patch repairs and Renderoc mortars on RCC bridge piers, decks and soffits suffering carbonation and chloride-induced spalling across NCR highway and flyover structures.
Water & sanitation
SBR-grade bonding of repair mortars and renders in water tanks, STPs, sumps and basements where water resistance at the interface is essential.
Commercial & residential RCC repair
Reattaching new concrete to old on columns, beams, chajjas and slabs during structural rehabilitation of ageing buildings in Delhi, Gurugram and Noida.
Industrial flooring & screeds
Bonding cementitious screeds and toppings to existing factory and warehouse floors to stop delamination under traffic and thermal movement.
Heritage & facade restoration
Gauging liquid and bond coat for thin-section renders on masonry and concrete facades where a low-profile, well-keyed repair is required.
Marine & coastal structures
SBR-modified bonding for repairs on chloride-exposed coastal RCC, jetties and splash-zone elements where durability of the new-to-old bond is critical.
Frequently asked questions
What does ‘Nitobond Betonklæber’ actually mean?
Is this a single specific product or a range?
Which grade should I use — acrylic, SBR or epoxy?
Can I place repair mortar onto the bond coat at any time?
How do I prepare the surface?
How does it compare to Sika, Dr. Fixit and STP bonding agents?
Does Space Arc supply this in Delhi NCR and across India?
How we position Fosroc Nitobond Betonklæber
Nitobond Betonklæber is best understood as the Danish-market badge for Fosroc’s Nitobond concrete bonding-agent family rather than a unique formulation — so the right way to specify it in India is by grade. Within the Fosroc range it pairs with Nitoprime Zincrich (steel primer), Renderoc repair mortars and Dekguard/Nitocote protective coatings to form a complete, mutually-compatible repair system, and it steps up to Nitobond EP (two-part epoxy) when the substrate is permanently damp or the bond must be structural. Against the wider Indian market it sits head-to-head with Sika Latex and SikaTop Armatec, Dr. Fixit Pidicrete URP, STP/MBS SBR bonding agents and BASF/MBS Concresive bonding aids — all built on the same acrylic/SBR/epoxy polymer principles. The honest differentiator is not the chemistry, which is broadly equivalent across brands, but the integrated, warranted Fosroc repair system and the technical support Space Arc provides around grade selection, surface preparation and curing.
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