Sika Sikadur-53 UF Grout
A three-part, water-displacing epoxy grout that sets hard underwater, delivering high early strength for anchoring and repair where cementitious grouts simply wash out.
What is it?
A three-part, solvent-free epoxy grout (resin, hardener and graded filler) engineered to be poured into wet, damp or fully submerged cavities, where it displaces standing water and cures to a rigid, high-strength solid.
Where is it used?
Underwater and splash-zone works: anchoring starter bars and dowels in water-retaining structures, under-grouting bridge bearings and machine bases in damp plant rooms, and repairing submerged concrete in dams, jetties, intakes and sewage basins.
Why use it?
Because ordinary cement grouts dilute and lose strength when placed in water, while Sikadur-53 UF hardens without shrinkage even underwater and reaches roughly 20 N/mm compressive strength within three hours, letting work continue against the tide or plant schedule.
How is it applied?
Blend Parts A and B, add the filler (Part C) at a 2:1:8 ratio by weight, mix to a uniform pour, then place into the pre-soaked void in 10-50 mm layers so the grout pushes water ahead of it and fills completely.
About Sika Sikadur-53 UF Grout
Sikadur-53 UF Grout is Sika’s answer to a problem every site engineer working near water knows well: how do you anchor a bar, bed a bearing or patch a pier when the pour location is wet, damp or fully flooded and dewatering is impractical? It is a three-component epoxy system, supplied as a pre-batched resin (Part A), hardener (Part B) and specially graded filler (Part C). Once combined at the fixed 2:1:8 ratio by weight, the mix behaves as a free-flowing, water-insensitive grout that can be poured straight into a submerged cavity, physically pushing water out of the way as it settles and then curing into a dense, load-bearing solid.
What sets it apart from a normal cementitious grout is that its strength does not depend on staying dry. Cement grouts placed underwater tend to bleed, segregate and wash out, leaving a weak, porous mass. Sikadur-53 UF instead relies on an epoxy reaction that is largely indifferent to moisture, so it hardens without shrinkage whether the surrounding concrete is dry, damp or several metres under the surface. For contractors in India that translates into fewer cofferdams, less dewatering and the ability to carry out anchoring and repair in monsoon conditions, tidal zones and live water-retaining structures without waiting for a dry window.
The technical insight
The core of the product is a two-part epoxy binder that cures by chemical cross-linking rather than by drying, which is why water on the substrate does not stop it setting. When the mixed grout is poured into a flooded void, the epoxy phase is denser and non-miscible with water, so it flows to the bottom and displaces the water upward and out, forming an intimate bond directly against the wetted concrete, stone or steel. The graded filler (Part C) does the structural heavy lifting: it packs the matrix to control exotherm, minimise shrinkage and build compressive strength quickly, reaching around 20 N/mm at three hours, 60 N/mm at one day and 80 N/mm at seven days. Because the cured epoxy is effectively impermeable, it also seals the anchorage against further moisture and oxygen ingress, which protects embedded steel from corrosion. The fixed 2:1:8 batching and the pre-weighed packs remove the guesswork that usually undermines site-mixed epoxy grouts, so the reaction chemistry stays correct even in awkward, wet placements.
Where it is used
- Anchoring starter bars, dowels and reinforcement into damp or submerged concrete in water-retaining structures
- Under-grouting and bedding of bridge bearings and crane rails where the seating is wet or exposed to standing water
- Grouting machine base plates and holding-down bolts in damp plant rooms, pump houses and pits
- Repair of submerged and splash-zone concrete on dam faces, spillways, intakes and stilling basins
- Fixing tie-rods, anchors and fasteners in sewage treatment tanks, water reservoirs and effluent basins
- Rebuilding spalled or eroded sections of piers, jetty legs and marine piles below the waterline
- Sealing and grouting around penetrations and construction joints in wet basements and underground structures
- Patch repair of industrial floors in continuously wet or wash-down process areas
Key advantages
- Places and cures reliably underwater and in damp conditions, removing the need for extensive dewatering or cofferdams
- Displaces standing water as it is poured, bonding directly to the wetted substrate
- Very high early strength, around 20 N/mm at three hours, allowing rapid return to service or continued works
- Shrinkage-free hardening that keeps anchors and bearings tightly and accurately seated
- Strong adhesion to concrete, masonry, stone and steel for durable structural fixings
- Solvent-free and effectively impermeable once cured, sealing the repair against moisture and oxygen
- Supplied as pre-batched packs with a fixed 2:1:8 ratio, so site mixing errors are minimised
- Suitable across a wide working range, from dry through damp, wet and fully submerged placements
Limitations & considerations
- A three-part epoxy system, so it is more expensive per litre than cementitious grouts and is best reserved for genuinely wet or high-performance situations
- Placement is limited to 10-50 mm per layer; deeper voids must be filled in successive lifts, adding time
- Pot life is short (over 20 minutes for 100 g at 30C) and shrinks further with larger batches and higher temperatures, so mixing and pouring must be planned and paced
- Application is intended for substrate and ambient temperatures roughly between +10C and +40C; very cold or very hot sites need adjustment or advice
- The epoxy is denser than water but can still be disturbed by strong currents, so the pour zone should be kept as still as practical during placement
- Not a free-flow, large-gap machinery grout for dry bases with big clearances; a dedicated dry-condition epoxy grout is more economical there
Selection & best practice
Start by cleaning the substrate of loose material, laitance, oil and marine growth, then keep it saturated rather than trying to dry it. Confine the pour with formwork or a boxed head so the grout can build a positive placing pressure that helps drive water out. Add Parts A and B together first and blend for about a minute with a slow-speed paddle (under 400 rpm), then work in the full filler (Part C) until the colour and consistency are uniform; never leave A and B mixed without the filler, as the exotherm can run away. Pour from one side only so the grout advances as a single front and pushes water ahead of it, avoiding trapped pockets, and keep individual layers within 10-50 mm. Mix only what the crew can place inside the pot life, and remember that warm weather and larger masses shorten that window sharply. Protect the placement from strong flow or wave action until it has gained initial strength.
Specifications
| Product type | Three-part, solvent-free, moisture-tolerant pourable epoxy grout |
| Mixing ratio (A:B:C) | 2 : 1 : 8 by weight |
| Pack size | 11 kg pre-batched set (Part A 2 kg + Part B 1 kg + Part C 8 kg); also supplied 11 kg x 2 |
| Fresh mortar density | 1.9 +/- 0.1 kg/L |
| Layer thickness | 10-50 mm per layer |
| Compressive strength | >=20 N/mm at 3 h, >=60 N/mm at 1 day, >=80 N/mm at 7 days |
| Pot life | >20 minutes (100 g at +30C) |
| Application temperature | +10C to +40C (substrate and ambient); dry, damp, wet or underwater |
| Reference standards | ASTM C882 (adhesion), EN ISO 2811-1 (density), FIP 5.1 (pot life) |
Industry use cases
Dams and hydraulic structures
Underwater repair of eroded spillway and stilling-basin concrete and anchoring of fixings on dam faces without lowering reservoir levels.
Water and wastewater treatment
Fixing tie-rods, anchors and fasteners inside live reservoirs, clarifiers and effluent basins where the surfaces stay permanently wet.
Ports, jetties and marine works
Rebuilding spalled pier and pile sections in tidal and splash zones and bedding bearings that sit close to the waterline.
Bridges and infrastructure
Under-grouting bridge bearings and seating crane rails where drainage keeps the location damp or subject to standing water.
Industrial and process plants
Grouting machine base plates and holding-down bolts in wash-down bays, pump pits and plant rooms that cannot be fully dried.
Frequently asked questions
Can Sikadur-53 UF Grout really be placed underwater without dewatering?
How is it different from a cementitious grout like a Conbextra GP or an UltraTech grout?
How quickly does it gain strength?
What thickness can I pour in one go?
How much working time do I have after mixing?
How is it supplied and how much do I need?
How we position Sika Sikadur-53 UF Grout
Sikadur-53 UF Grout is the specialist to reach for when the placement is wet, damp or underwater and cementitious grouts would wash out. Within the Sika family, pair it with an epoxy bonding or anchoring resin such as a Sikadur adhesive for dry structural fixings, and step up to a Sika cementitious precision grout (SikaGrout range) for large-volume, dry machine bedding where the economics favour cement. Across the brands we distribute, our Fosroc Conbextra epoxy and cementitious grouts, MC-Bauchemie and UltraTech grouts cover the dry and general-purpose end of the same task, while Sikadur-53 UF stays the honest recommendation whenever water is the deciding factor.
Fosroc Conbextra EPR — Specify the Fosroc epoxy grout when the base is dry and the job is a large-gap (10-120 mm), high-vibration machinery bedding, rather than the wet or submerged placement that Sikadur-53 UF is built for.
Related Grouts & Anchors products
Source Sika Sikadur-53 UF Grout for your project
Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.