Fosroc Nitobond EP03
A 100% solids, two-part epoxy bonding bridge for structural new-to-old concrete connections on roads, bridges and industrial floors.
What is it?
Fosroc Nitobond EP03 is a 100% solids, two-component (base + hardener) epoxy-resin concrete bonding agent that creates a high-strength adhesive bridge between freshly placed concrete or mortar and an existing hardened cementitious substrate.
Where is it used?
Used on horizontal and vertical surfaces (including formwork applications) for roads, bridges, loading bays, machine bases and industrial repairs, both indoors and outdoors, across new construction and rehabilitation projects.
Why use it?
Because it is solvent-free and 100% solids, it forms a durable, non-shrinking bond with high mechanical and chemical resistance, giving a monolithic new-to-old concrete joint that ordinary cement slurry or SBR latex cannot match for structural duty.
How is it applied?
The pre-weighed base and hardener are mixed thoroughly, brush- or roller-applied to a clean, sound, saturated-surface-dry substrate at 0.3-0.4 kg/m2, and fresh concrete or mortar is placed onto the still-tacky film within the placing time (about 4 hours at 20C).
About Fosroc Nitobond EP03
Fosroc Nitobond EP03 belongs to the long-established Nitobond family of concrete bonding agents, but sits at the structural, heavy-duty end of that range. Unlike the water-based Nitobond SBR (a styrene-butadiene latex) or the emulsion-grade Nitobond EP, the EP03 grade is a 100% solids epoxy system: it contains no solvent and no water carrier that has to evaporate before it can work. That single fact governs almost everything an engineer needs to know about it. The product is supplied as two pre-weighed components, a resin base and a hardener, which are combined on site immediately before use. Once mixed, it is applied as a thin film to a prepared substrate and the new concrete, screed or repair mortar is cast directly against the wet, tacky coating so that the epoxy cures in intimate contact with both the old surface and the new placement. The result is a bond line that, when correctly executed, is stronger than the parent concrete itself, meaning failure under test typically occurs in the concrete rather than at the interface. For Space Arc Engineering’s clients across Delhi NCR and Pan-India, EP03 is the answer to a recurring site problem: how to make new concrete stick reliably and permanently to old concrete in situations where the joint will carry real structural or dynamic load. Typical settings include road and bridge rehabilitation, loading docks, industrial floors, plinths and machine foundations, and any large-scale repair where a feather edge or thin overlay would otherwise debond. It is equally at home on vertical and soffit pours behind formwork, where its non-sag tack film holds the interface together during placing. Because it is 100% solids, it can also serve as a protective barrier coat between an aggressive substrate and a new repair, or as a pre-passivating layer ahead of screed mortars in concrete structure repairs.
The technical insight
The defining property of Nitobond EP03 is that it is a 100% solids epoxy, not an emulsion. A water-based latex bonding aid (SBR) or an epoxy emulsion must lose its carrier before the polymer film coalesces and develops strength; in humid, enclosed or cold conditions that drying can be incomplete, leaving a weak, re-emulsifiable layer at the very interface you are trying to strengthen. EP03 has nothing to evaporate. The base and hardener chemically cross-link into a rigid, insoluble thermoset that is unaffected by trapped moisture, so it can be used in formwork pours and on damp (though not standing-water) substrates where a film-forming product would be marginal. The practical consequence for the engineer is the placing time, often called the open or wet-on-wet window: fresh concrete must be cast onto the EP03 film while it is still tacky, roughly within 4 hours at 20C. That window shortens significantly as ambient and substrate temperatures rise, which matters acutely on Indian sites where deck temperatures of 35-45C are common. If the film cures hard before the topping is placed, the chemical bond is lost and the layer instead behaves as a debonding membrane. Equally, because the product is rigid epoxy rather than a flexible latex, EP03 is engineered for monolithic, load-bearing repairs rather than for situations needing movement accommodation. Surface preparation discipline, mechanically roughened, sound, clean and saturated-surface-dry concrete, is what converts the chemistry into the high interface strength that the laboratory slant-shear and pull-off data promise.
Where it is used
- Bonding fresh concrete or mortar to existing hardened concrete in road and pavement reconstruction
- Structural concrete repair on bridges, decks, beams, columns and soffits
- Loading bays, dock levellers and heavy-duty industrial floor repairs and overlays
- Machine bases, plinths and equipment foundations where a thin new topping meets old concrete
- Vertical and overhead repairs cast behind formwork where the bond must hold during placing
- Pre-passivating screed or barrier coat between an aggressive substrate and a new repair layer
- New-to-old connections in extensions, infill bays and construction joints carrying structural load
Key advantages
- 100% solids and solvent-free, so there is no carrier to evaporate and no weak interfacial film, allowing use in formwork and enclosed pours
- Develops a bond stronger than the parent concrete, so correctly tested joints fail in the concrete rather than at the interface
- High mechanical strength and good chemical resistance suited to structural, load-bearing and dynamically loaded repairs
- Works on both horizontal and vertical surfaces and tolerates damp (saturated-surface-dry) substrates that defeat latex bonding aids
- Supplied as pre-weighed two-component packs, removing on-site batching error and ensuring correct resin-to-hardener ratio
- Economical in use at 0.3-0.4 kg/m2 coverage, giving predictable consumption for estimating
- Doubles as a barrier or pre-passivating coat, adding versatility within a single repair system
Limitations & considerations
- Strictly a wet-on-wet system: concrete must be placed within the placing time (about 4 hours at 20C) or the cured film becomes a debonding layer
- Open time shortens sharply at high temperatures, demanding careful planning on hot Indian sites and smaller mixed batches
- Rigid epoxy, not a flexible latex, so it is not intended for joints needing crack-bridging or movement accommodation
- Performance depends entirely on substrate preparation; oil, laitance, dust or standing water will cause failure regardless of product quality
- Two-component epoxy with a finite pot life once mixed; over-ordering a single batch risks wastage if the working time is exceeded
- Higher unit cost than SBR or cementitious slurry bonding aids, so best reserved for genuinely structural new-to-old connections
- Epoxy resins can cause skin sensitisation; gloves, eye protection and ventilation are required during handling
Selection & best practice
Mechanically prepare the substrate to a sound, clean profile by grit-blasting, scabbling or needle-gunning, removing all laitance, curing compound, oil and dust, then bring it to a saturated-surface-dry condition with no standing water. Stir each component separately, combine the full pre-weighed base and hardener and mix for at least three minutes with a slow-speed paddle until uniform, mixing only as much as can be used within the pot life. Apply the EP03 as a continuous film by stiff brush or roller at 0.3-0.4 kg/m2, working it well into the prepared surface, then place the fresh concrete, screed or repair mortar onto the still-tacky film before the placing window closes, around 4 hours at 20C and considerably less in hot weather. On large or hot pours, work in manageable bays so no coated area is left exposed past its open time, and never let the film cure hard before topping. Clean tools immediately after use and always confirm the latest project-specific values against the current Fosroc TDS for the site temperature.
Specifications
| Product type | Two-component (base + hardener) epoxy-resin concrete bonding agent |
| Solids content | 100% solids, solvent-free |
| Primary function | Bonding fresh concrete / mortar to existing hardened cementitious substrates |
| Coverage | 0.3 – 0.4 kg/m2 (varies with substrate texture) |
| Placing time (open / wet-on-wet window) | Approx. 4 hours at 20C; reduces at higher temperatures |
| Application surfaces | Horizontal and vertical, including formwork (cast-against) applications |
| Application method | Stiff brush or roller onto prepared, saturated-surface-dry substrate |
| Mixing | Full base into hardener, mechanically mixed approx. 3 minutes with slow-speed paddle |
| Typical end uses | Roads, bridges, loading docks, industrial floors, plinths; indoor and outdoor |
| Reference standard (epoxy bonding family) | Slant-shear / bond strength assessed to BS 6319 (confirm grade-specific TDS) |
| Storage | Store in cool, dry conditions in original unopened packs, away from heat |
Industry use cases
Highways and bridges
Reinstating worn or spalled carriageway slabs and bridge deck repairs where a new concrete overlay must bond structurally to the retained old deck under traffic loading.
Industrial and warehousing
Repairing and overlaying heavy-duty floors, loading docks and dock-leveller pits where thin new toppings would otherwise debond under fork-lift and impact loads.
Power, process and manufacturing plants
Casting new machine bases, pump plinths and equipment foundations against existing concrete so the joint resists vibration and dynamic load.
Building rehabilitation
Structural repair of beams, columns and soffits in ageing RCC buildings, bonding repair concrete to the parent member as part of a Renderoc or microconcrete repair system.
Water-retaining and infrastructure structures
Joining new concrete to old in tanks, channels and culverts where a reliable, non-re-emulsifiable bond line is required in permanently damp conditions.
Frequently asked questions
Is Nitobond EP03 the same as Nitobond EP?
What is the difference between Nitobond EP03 and Nitobond SBR?
How long do I have to place concrete after applying EP03?
Can Nitobond EP03 be used on damp or vertical surfaces?
What coverage and pack planning should I allow?
Does Space Arc Engineering supply genuine Fosroc Nitobond EP03 in India?
Is Nitobond EP03 suitable for crack repair or moving joints?
How we position Fosroc Nitobond EP03
Within the Fosroc range, Nitobond EP03 is the structural, 100% solids epoxy option that sits above the water-based Nitobond SBR latex and the general-purpose Nitobond EP, and it is most often specified alongside Fosroc repair systems such as the Renderoc range of repair mortars, Conbextra grouts and Nitoprime primers, where a high-integrity new-to-old bond line is the critical detail. Engineers should choose EP03 specifically when the joint is load-bearing or dynamically loaded; for routine, non-structural bonding of screeds and patch repairs, Nitobond SBR is usually the more economical and practical choice. Against the wider Indian market, EP03 competes with Sika’s epoxy bonding bridges such as Sikadur-32, MBS (MYK Schomburg) epoxy bonding agents, STP’s epoxy systems and, at the general-purpose end, Dr. Fixit’s latex and bonding products, all of which are credible alternatives depending on availability, specification approval and price. The reason clients in Delhi NCR and Pan-India come to Space Arc Engineering for Nitobond EP03 is assurance of supply: genuine, batch-traceable Fosroc material backed by authorised-distributor technical support, current data sheets and applicator experience, so the specified structural bond is what actually gets built on site.
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