Sika MonoTop-3400 Abraroc
A single-component, hydraulic-abrasion-resistant structural repair mortar (formerly Sika Abraroc SR) built for spillways, stilling basins, pump sumps and heavy-duty industrial floors.
What is it?
A one-part, cementitious repair mortar carrying sulphate-resistant cement, fibres and specially selected abrasion-resistant aggregates. It is EN 1504-3 Class R4 rated and reaches roughly 85 MPa compressive strength at 28 days, with an A6 wear classification.
Where is it used?
Concrete surfaces that take relentless mechanical or hydraulic wear: spillways, stilling basins, dam aprons, sewer inverts, pump sumps, marine and water-retaining structures (water pH > 4), plus silo floors, loading bays and industrial slabs.
Why use it?
Ordinary repair mortars erode where fast water carries silt and grit, or where forklift and steel-wheel traffic grinds a floor down. Abraroc is formulated so its worn resistance sits close to natural granite, giving repairs that survive abrasion instead of washing away.
How is it applied?
Mixed with 2.75 litres of clean water per 25 kg bag, then hand-placed or dry-sprayed at 10-50 mm per layer over a pre-wetted, primed substrate. Working time is about 15 minutes at 20 degrees C; overcoat after 24 hours and cure against premature drying.
About Sika MonoTop-3400 Abraroc
Sika MonoTop-3400 Abraroc is Sika’s answer to a problem most repair mortars quietly fail at: surviving the grinding, scouring action of moving water and heavy mechanical traffic. Rebranded from the long-established Sika Abraroc SR, it is a factory pre-blended, single-component mortar that only needs the addition of clean water on site. The formulation combines sulphate-resistant cement, reinforcing fibres and a graded blend of hard, abrasion-resistant aggregates (up to 2.6 mm), which together give the hardened mortar a wear resistance that Sika benchmarks against granite. For consultants specifying repairs on hydraulic assets across India, that abrasion pedigree is the whole point.
Its structural credentials are just as strong as its wear numbers. Abraroc is CE-marked to EN 1504-3 as a Class R4 structural repair product and also declared under EN 13813 as an internal cementitious screed material, so it does double duty as both a load-bearing reinstatement mortar and a hard-wearing topping. It develops around 85 MPa in compression and roughly 11 MPa in flexure at 28 days, with tensile adhesion of at least 2.0 MPa to a properly prepared substrate. It can be laid up to 50 mm thick in a single pass, vertically or horizontally, by trowel or by dry-spray gun, which makes it practical for both small patch repairs and large-area resurfacing of worn concrete.
The technical insight
Abrasion resistance in cementitious mortars is really a contest between the hardness of the aggregate and the strength of the paste holding it. In a normal mortar, moving water or grit plucks softer aggregate and paste loose, and the surface recedes. Abraroc is engineered so both halves of that equation win: the aggregates are deliberately hard and angular, and the sulphate-resistant cement matrix around them is dense and high-strength (roughly 85 MPa at 28 days). Sika quantifies the result with the CNR wet-abrasion method, where a lower material-resistance index means better wear performance. Abraroc scores 0.5-0.6, sitting within the same band as natural granite (0.35-0.8) and far below glass, the reference at 1.0. On the dry side it earns an A6 rating under EN 13892-3 and a Böhme wear loss below 6 cm3/50 cm2. Sulphate-resistant cement matters here too, because the same assets that see abrasion, sewers, dams, marine works, also see aggressive water; the binder chemistry resists sulphate attack while the aggregate resists the mechanical scouring.
Where it is used
- Repair and resurfacing of spillways, stilling basins and dam aprons subject to fast, silt-laden water
- Lining and invert repair of sewer pipes and sewage-treatment structures exposed to hydraulic abrasion
- Reinstatement of pump sumps, channels and other water-conveyance surfaces
- Abrasion-resistant protective topping over structural concrete repairs
- Repair of marine and maritime structures exposed to sea water and aggressive conditions
- Refurbishment of industrial floors, silo floors, loading bays and storage areas under heavy mechanical loads
- Structural reinstatement of spalled, delaminated or damaged concrete (EN 1504-9 Principle 3)
- Restoring cover and passivity to reinforcement in deteriorated infrastructure (EN 1504-9 Principle 7)
Key advantages
- Exceptional hydraulic abrasion resistance, benchmarked against granite via the CNR wet-abrasion index
- High structural strength: around 85 MPa compressive and 11 MPa flexural at 28 days
- EN 1504-3 Class R4 rated for genuine structural repair, not just cosmetic patching
- Single-component, ready to mix with only water, so no on-site batching of admixtures
- Placed up to 50 mm thick in one layer on vertical or horizontal faces, cutting the number of passes
- Applied by hand or by dry-spray gun, suiting both small patches and large scoured areas
- Resistant to sea water and aggressive water conditions thanks to sulphate-resistant cement
- Non-combustible (Reaction to Fire Class A1) and low soluble chloride content (below 0.05 percent)
Limitations & considerations
- Layer thickness is bounded: minimum 10 mm and maximum 50 mm per lift, so very thin skims or single thick pours outside this band are not suitable
- Short working window of roughly 10-20 minutes depending on temperature, so mix only what the crew can place
- Water dosage is fixed at 2.75 litres per 25 kg bag; over-watering to ease workability weakens the mortar and causes cracking and discolouration
- Requires a correctly prepared, saturated-surface-dry substrate and, for hand work, the right bonding primer, so it is unforgiving of poor surface preparation
- Application and substrate temperatures must stay between +5 and +30 degrees C, and it must be protected from direct sun, strong wind and freezing while curing
- Not a decorative or self-levelling floor material; the finish is a functional textured surface, and floors needing a smooth aesthetic topping may need a separate system
Selection & best practice
Preparation decides the outcome. Remove all delaminated, weak or contaminated concrete back to a sound substrate, and clean exposed reinforcement to Sa 2 by abrasive blasting or high-pressure water jetting. Where corrosion protection is called for, coat rebar with Sika MonoTop-910 N (normal use) or SikaTop Armatec-110 EpoCem (demanding conditions). Keep repair areas to simple square or rectangular shapes to avoid shrinkage-stress concentrations. Pre-wet the substrate for about two hours before placing and bring it to a dark, matt, saturated-surface-dry condition with no standing water in the pores. For hand application over green concrete use a SikaLatex or SikaTop-121 bonding primer; over cured 28-day concrete use Sikadur-32 LP; sprayed application generally needs no primer. Mix at 2.75 litres of water per 25 kg bag using a slow-speed (below 500 rpm) drill or forced-action mixer for at least three minutes, and never exceed the water dosage. Place between 10 and 50 mm per lift, building up wet-on-wet only after each layer has stiffened. Finish with a damp sponge after about an hour, then protect against premature drying using a curing membrane, wet geotextile or polythene.
Specifications
| Standard / Class | EN 1504-3 Class R4 (structural repair); also EN 13813 |
| Chemical base | Sulphate-resistant cement, fibres, additives, abrasion-resistant aggregates |
| Compressive strength | ~30 MPa (1d), ~45 MPa (2d), ~65 MPa (7d), ~85 MPa (28d) (EN 12190) |
| Flexural strength | ~11 MPa at 28 days (EN 12190) |
| Tensile adhesion strength | greater than or equal to 2.0 MPa (EN 1542) |
| Abrasion / wear resistance | A6 (EN 13892-3); Bohme below 6 cm3/50 cm2; CNR index 0.5-0.6 (granite 0.35-0.8) |
| Layer thickness | Min. 10 mm / max. 50 mm per layer |
| Water demand / yield | 2.75 L water per 25 kg bag; ~12.3 L mortar yield; ~21 kg powder per m2 per cm |
| Packaging / working time | 25 kg bag; ~15 min working time at 20 degrees C; overcoat after 24 h |
Industry use cases
Dams & Hydraulic Structures
Rebuilding scoured spillways, stilling basins and dam aprons where high-velocity, silt-laden water strips ordinary repairs; the granite-class wear resistance is the deciding factor.
Water & Wastewater
Relining sewer inverts, pump sumps and treatment-plant channels that face constant hydraulic abrasion and aggressive water (pH > 4), using the sulphate-resistant binder.
Ports & Marine
Repairing jetties, sea walls and other maritime concrete exposed to sea water and tidal scouring, where sulphate resistance and abrasion resistance must coexist.
Industrial Flooring
Resurfacing silo floors, loading bays and factory slabs worn by forklift, steel-wheel and abrasive traffic, laying a hard-wearing 10-50 mm topping over structural repairs.
Frequently asked questions
What makes Abraroc different from a standard concrete repair mortar?
How much water do I add per bag, and can I add more for workability?
Can it be sprayed, or is it hand-applied only?
What thickness can I build in one pass?
Do I need a bonding primer and rebar protection?
Is it suitable for structures in contact with aggressive or sea water?
How we position Sika MonoTop-3400 Abraroc
Sika MonoTop-3400 Abraroc is a specialist within Sika’s MonoTop repair family. Where the wear challenge is milder and the job is general structural reinstatement, Sika MonoTop-4012 or the wider MonoTop range are more economical choices; Abraroc earns its place specifically where hydraulic abrasion or heavy mechanical wear is the governing problem. Pair it with its own system partners we stock, Sika MonoTop-910 N or SikaTop Armatec-110 EpoCem for rebar protection, and SikaLatex, SikaTop-121 or Sikadur-32 LP as bonding primers, to deliver the full manufacturer-specified repair build-up. For hard-trafficked industrial floors, Sika’s Chapdur dry-shake surface hardeners complement Abraroc where a new slab needs an abrasion-resistant wearing surface rather than a repair. Across our other brands, Dr. Fixit and MC-Bauchemie also offer concrete-repair mortars, though for genuinely abrasion-critical hydraulic work Abraroc remains the sharper specification.
Fosroc Renderoc S2 — A specifier standardised on Fosroc for structural concrete repair, and not facing a hydraulic-abrasion problem, may prefer Renderoc S2 as a Class-grade, hand-applied reinstatement mortar in the same 10-50 mm range, though it lacks Abraroc’s granite-class abrasion resistance.
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