Fosroc Nitobond AR Std
Single-component latex acrylic polymer emulsion that bonds new mortar to old concrete, modifies cementitious mixes and adds waterproofing – the workhorse primer for Renderoc and polymer-modified repairs.
What is it?
A single-component, water-based latex acrylic polymer emulsion that works as a bonding aid, cement modifier and waterproofing additive for cementitious systems. Being acrylic, it is hydrolysis-resistant and suitable for external and damp conditions.
Where is it used?
Concrete repair and rehabilitation – bonding fresh repair mortar, screeds, renders and floor toppings to existing concrete, masonry, plaster and blockwork; priming substrates ahead of Renderoc patch repairs; and gauging polymer-modified mortars on bridges, water tanks, RCC structures, floors and facades.
Why use it?
It overcomes the weak interface between old hardened concrete and new mortar, where most repairs fail. It improves tensile, flexural and adhesion strength, resists hydrolysis for external use, reduces bleeding/segregation, and is ready to use with no site mixing of the emulsion itself.
How is it applied?
Saturate and pre-wet the prepared substrate, scrub the emulsion in as a bonding coat, then apply repair mortar wet-on-wet while the primer is still tacky (within ~15 minutes at 30C). For modifying mortars/screeds, the emulsion is gauged into a dry cement-sand mix at the prescribed ratio.
About Fosroc Nitobond AR Std
Fosroc Nitobond AR Std is one of the most widely specified bonding agents in Indian concrete repair, and for good reason: it solves the single biggest cause of patch-repair failure, the weak bond line between aged concrete and new mortar. It is a single-component latex acrylic polymer emulsion – a milky white liquid that needs no site mixing of the emulsion itself, only correct gauging when used to modify a mortar. The “AR” denotes its acrylic chemistry, which is resistant to hydrolysis (breakdown by water/alkali over time). That distinction matters in the field: unlike older PVA/redispersible bonding agents that can soften and lose grip when re-wetted, the acrylic film stays stable, so Nitobond AR Std can be used externally and in permanently damp or intermittently wet locations where many cheaper bonding aids cannot. The “Std” suffix is the standard-grade India SKU, distinct from the higher-performance Nitobond SBR (styrene-butadiene) latex used for heavier-duty structural bonding. In practice the product wears three hats on a single site. As a bonding aid it is scrubbed into a pre-wetted substrate and the repair mortar is laid wet-on-wet while it is tacky. As a cement modifier it is gauged into a dry cement-and-quartz-sand blend to produce a polymer-modified mortar or screed with markedly better tensile, flexural and adhesion properties than plain sand-cement. As a waterproofing additive, a small percentage by weight of cement is mixed into concrete to cut permeability. For contractors, consultants and procurement teams across Delhi NCR and Pan-India, it is the dependable, economical primer that pairs naturally with the Fosroc Renderoc repair-mortar family and is stocked in convenient 1, 5 and 20 litre packs.
The technical insight
The performance of Nitobond AR Std lives or dies on the “tacky window.” Verified Fosroc India data shows the repair mortar must go on while the bonding coat is still tacky – a satisfactory bond can be achieved up to about 15 minutes after application at 30C, but if the film is allowed to dry fully the initial “grab” to the repair mortar is reduced. At higher Indian summer temperatures this overlay window shortens, which is why the TDS explicitly warns that on hot days the overlay mortar must not be applied once the bonding aid has gone totally dry; temporary shuttering is recommended to keep work wet-on-wet. The polymer also genuinely upgrades the mortar it gauges: against a control mix, Fosroc reports 28-day compressive strength rising to about 22 N/mm2 (control 18-20, ASTM C109), flexural strength to about 5 N/mm2 (control 3.0, ASTM C348) and slant-shear adhesion to concrete to about 5 N/mm2 (control 3.5, ASTM C882). One honest limitation the data sheet flags: as a bonding agent it cannot act as a barrier coat against chloride-ion ingress from the substrate – so in chloride-contaminated or marine repairs, corrosion of exposed rebar must be addressed separately (e.g. priming steel with Nitocote AP35 / a zinc-rich primer) rather than relying on the bond coat.
Where it is used
- Bonding fresh repair mortar to old concrete in patch repairs and reinstatement of worn-out or damaged RCC
- Priming substrates ahead of Fosroc Renderoc hand-applied repair mortars
- Gauging liquid for polymer-modified mortars, screeds and floor toppings
- Bonding renders and plaster to concrete, masonry, stonework and blockwork
- Improving impermeability/waterproofing of concrete as a 2-5% (by weight of cement) additive
- Bedding and bonding coat for thin-section toppings where a strong mechanical key is required
- Repair of spalled columns, beams, slabs, chajjas and water-retaining structures (with appropriate rebar treatment)
Key advantages
- Hydrolysis-resistant acrylic chemistry – suitable for external and damp/wet applications where PVA bonding agents fail
- Strong adhesion to concrete, masonry, stonework, plaster and blockwork
- Improves tensile, flexural and adhesion (slant-shear) strength of the mortar it gauges
- Single component – no site mixing of the emulsion; easy brush or spray application
- Compatible with all common hydraulic (Portland) cements
- Reduces bleeding and segregation, improving cohesion of fresh mortar
- Doubles as a curing aid for the repair mortar to prevent rapid drying
- Economical, widely available, and pack sizes (1/5/20 L) suit both small and large jobs
Limitations & considerations
- Not a chloride barrier – cannot stop chloride-ion ingress from the substrate; rebar in contaminated concrete needs separate priming/protection
- Short overlay/tacky window, which shrinks further in hot weather – mortar must be applied wet-on-wet before the film dries
- Minimum application temperature 10C; do not apply if temperature is expected to fall, and protect from frost
- Standard-grade product – for heavier structural or high-movement bonding, SBR-based latex (e.g. Nitobond SBR) is generally preferred
- Performance depends heavily on correct surface preparation (clean, sound, mechanically keyed, pre-wetted substrate)
- Not a substitute for structural-grade epoxy bonding agents where a rigid, high-strength chemical bond is specified (use Nitobond EP for that)
- Slightly alkaline – skin/eye contact should be avoided; not designed as a standalone waterproof membrane
Selection & best practice
Achieve a clean, sound, mechanically keyed substrate – remove laitance, dust, oil and corrosion deposits and roughen smooth surfaces by scabbling, needle gun or grit-blasting. Expose and clean any reinforcement fully around its circumference and prime it (e.g. Nitocote AP35) before repair. Thoroughly dampen the concrete with water, brush off any excess, then scrub Nitobond AR Std into the surface, avoiding puddling. Apply the repair mortar wet-on-wet while the bonding coat is still tacky (within ~15 minutes at 30C; less in hotter weather) – never overlay onto a fully dried film. When modifying a mortar, dry-mix the cement and graded quartz sand first, then add it to the gauged liquid, keeping water content to the minimum. Cure the finished mortar and protect from frost and rain. Cut back edges to avoid feather-edging, work below a falling temperature of 10C only after consulting Fosroc, and wash all tools with clean water immediately after use.
Specifications
| Product type | Single-component latex acrylic polymer emulsion (bonding aid + cement modifier + waterproofing additive) |
| Appearance | Milky white liquid |
| pH | 9-10 (slightly alkaline) |
| Compressive strength @28d (ASTM C109) | ~22 N/mm2 (control 18-20) |
| Flexural strength @28d (ASTM C348) | ~5 N/mm2 (control 3.0) |
| Adhesion to concrete – slant shear (ASTM C882) | ~5 N/mm2 (control 3.5) |
| Mix – as cement modifier | 1 litre Nitobond AR Std : 5 kg cement : 15 kg graded quartz sand |
| Mix – as bonding agent | 0.5 part cement : 1 part Nitobond AR Std (by weight) |
| Dosage – as waterproofing agent | 2-5% of Nitobond AR Std by weight of cement |
| Coverage – as bonding agent | approx. 3-4 m2/litre (substrate dependent) |
| Coverage – as cement modifier/primer | approx. 6-8 m2/litre (substrate dependent) |
| Yield (modifier mix) | 21 kg polymer mortar (1:5:15) yields approx. 10-11 litres |
| Open/overlay time | Apply mortar while tacky; up to ~15 min after application at 30C |
| Minimum application temperature | 10C; do not apply if temperature is expected to fall |
| Application method | Brush or spray (scrubbed into pre-wetted substrate) |
| Pack sizes | 1 litre, 5 litre and 20 litre plastic containers |
| Shelf life | 12 months at 30C in original unopened packaging |
| Storage | Store in dry conditions; protect from frost |
| Health / fire | Non-toxic, non-flammable; slightly alkaline – avoid skin/eye contact |
| Reference TDS | Fosroc India INDIA/2005/922/B |
Industry use cases
Structural / RCC repair
Bonding new Renderoc repair mortar to spalled columns, beams and slabs where reinforcement corrosion or cover loss has occurred, restoring monolithic action at the repair interface.
Water-retaining & infrastructure
Bonding and modifying mortars on water tanks, sumps, channels and bridge elements – exploiting the acrylic hydrolysis resistance for damp/external exposure (rebar protection handled separately in chloride zones).
Flooring & screeds
As a gauging liquid for polymer-modified screeds and thin-section floor toppings, improving abrasion resistance, flexural strength and bond to the base slab.
Building facades & plaster
Bonding renders and plaster to concrete, masonry and blockwork on external elevations, reducing debonding and cracking of plaster coats.
Waterproofing upgrades
Dosed at 2-5% by weight of cement into concrete and mortars to lower permeability in bathrooms, terraces and below-grade elements as part of a wider waterproofing system.
Frequently asked questions
Is Nitobond AR Std an acrylic or SBR bonding agent?
What is the mix ratio for using it as a bonding coat?
How much area does one litre cover?
How long can I wait before applying the repair mortar?
Can it stop chloride attack on reinforcement?
What pack sizes and shelf life does it have?
How we position Fosroc Nitobond AR Std
Nitobond AR Std sits at the value-and-versatility end of Fosroc’s bonding range: an economical, hydrolysis-resistant acrylic primer that covers everyday patch-repair, render-bonding and mortar-modification work. Within the Fosroc family it pairs naturally with the Renderoc repair mortars it is designed to prime and cure, and with Nitocote AP35 for rebar priming. Where the job is more demanding, step up: Nitobond SBR (styrene-butadiene latex) gives tougher, more flexible structural bonding and better performance under sustained wet conditions, while Nitobond EP is a two-part epoxy bonding agent for rigid, high-strength chemical bonds and bonding new-to-old where structural continuity is critical. Against the wider Indian market, credible equivalents include Sika Latex / SikaTop bonding products and Sika Armatec for the epoxy/anti-corrosion role, MBS (MYK / formerly BASF) Master Emaco bonding agents, Dr. Fixit Pidicrete URP (SBR-based) and STP’s bonding latexes. Nitobond AR Std’s edge is its proven track record, ASTM-referenced strength gains, wide availability and triple function (bond + modify + waterproof) in a single, easy-to-use single-component pack – making it a safe default specification for general concrete repair where the higher cost of SBR or epoxy systems is not warranted. Space Arc Engineering, as an authorised Fosroc distributor and applicator, supplies it with application support across Delhi NCR and Pan-India.
Related Concrete Repair products
Source Fosroc Nitobond AR Std for your project
Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.