Sika ViscoFlow-5263 NS
A PCE-based superplasticiser built to hold slump over long haul distances and hot-weather pours, without the extra set retardation that older admixtures relied on.
What is it?
A modified polycarboxylate ether (PCE) liquid admixture from Sika, engineered specifically for slump retention rather than pure water reduction.
Where is it used?
Ready-mix plants with long transit times, large continuous pours, and hot-weather concreting across Delhi NCR and Pan-India projects.
Why use it?
It keeps concrete workable and pumpable for extended periods without slowing early strength gain, protecting mixes against cold-joint and rejection risk on site.
How is it applied?
Dosed at 0.2 to 2.0% by weight of cement, added to the mixing water or into the mixer after 50 to 70% of the water, with at least 60 seconds of wet mixing.
About Sika ViscoFlow-5263 NS
On any project where concrete has to travel far or sit in a hot transit mixer before it reaches the pump, slump loss is the quiet enemy. A mix that leaves the batching plant at a healthy flow can arrive stiff, unpumpable and, in the worst cases, headed for rejection at the gate. Sika ViscoFlow-5263 NS is Sika’s answer to exactly this problem: a polycarboxylate ether (PCE) admixture formulated not just to reduce water, but to hold the fresh properties of concrete steady over time. It is a light brown liquid with a density of around 1.11 kg/l, supplied ready to dose straight into the mix.
What sets a slump-retaining PCE apart from a conventional high-range water reducer is where the chemistry does its work. Rather than dispersing all the cement at once and then fading, ViscoFlow-5263 NS releases its dispersing action progressively, so the mix stays flowable through the transport and placing window. Because it conforms to IS 9103 and ASTM C494 and works across a wide band of water-cement ratios and ambient temperatures, it slots into most Indian RMC and structural mix designs without forcing a redesign. For contractors and consultants dealing with real-world haul distances and Indian summers, that predictability is the whole point.
The technical insight
The mechanism is time-controlled dispersion. Standard superplasticisers adsorb onto cement grains immediately and create their full dispersing effect up front, which is why slump peaks early and then drops away as hydration proceeds. ViscoFlow-5263 NS uses a modified polycarboxylate backbone whose side chains are engineered to become active in stages as the mix ages, effectively topping up the dispersion that early hydration consumes. This staggered release keeps particles separated and the paste mobile for longer. Critically, it achieves this through dispersion chemistry rather than by retarding the set, so the hydration clock keeps running normally and early strength development is not sacrificed for workability. The result is a flatter slump-versus-time curve, reduced tendency for drying shrinkage from over-watering on site, and denser, more durable hardened concrete because no one has to add water at the pump to save a stiffening load.
Where it is used
- Ready-mixed concrete facing long transit times between the batching plant and the site
- Large continuous pours such as rafts, mat foundations and thick slabs that must stay uniform end to end
- Hot-weather concreting where ambient heat accelerates slump loss
- Pumped concrete that needs consistent workability from the hopper to the point of placement
- High-rise and infrastructure projects with extended placing windows
- Mixes designed across a wide range of water-cement ratios and cement types
- Cold-weather placements where flow must be held without slowing the pour
- Congested reinforcement where sustained flowability aids full compaction
Key advantages
- Holds slump flow over extended periods, cutting the risk of stiff, rejected loads
- Maintains workability without adding extra set retardation, so early strength is protected
- Reduces the temptation to add water on site, which protects strength and durability
- Improves cement dispersion for a more cohesive, easier-to-pump mix
- Helps lower drying shrinkage by keeping the design water-cement ratio intact
- Performs reliably across varied temperatures and W/C ratios
- Conforms to IS 9103 and ASTM C494 for specification confidence
- Compatible with all common cements and cementitious materials
Limitations & considerations
- It is a slump retainer, not a set accelerator; it will not speed up stiffening or finishing
- Must never be added to dry aggregate or dry cement, only to water or the mixing sequence
- Effective dosage depends on cement, temperature and haul time, so trial mixes are essential
- Overdosing beyond the approved range can cause excessive retention or bleeding and needs consultant sign-off
- Requires controlled storage between +10 and +40 degrees C, away from frost and direct sunlight
- Shelf life is limited to 12 months from production in sealed, undamaged packaging
Selection & best practice
Always establish the correct dosage through site trial mixes rather than assuming a figure, because the right rate shifts with your cement, ambient temperature and how long the concrete must stay workable. Add ViscoFlow-5263 NS to the mixing water, or introduce it into the mixer once 50 to 70% of the water is already in, and never onto dry cement or aggregate where it cannot disperse. Allow a minimum of 60 seconds of wet mixing after dosing so the admixture is fully distributed. Keep drums sealed and stored between +10 and +40 degrees C, protected from frost and direct sun, and use stock within its 12-month shelf life. For unusually long haul times or extreme heat, agree any dosage above the standard band with the mix designer or consultant before batching.
Specifications
| Chemical Base | Modified polycarboxylate ether (PCE) solution |
| Appearance | Light brown liquid |
| Density | Approx. 1.11 kg/l at 25 degrees C |
| pH Value | Minimum 6 |
| Dosage Range | 0.2% to 2.0% by weight of cementitious material |
| Standards | IS 9103 and ASTM C494 |
| Packaging | 255 kg drums; bulk supply available |
| Storage | +10 to +40 degrees C, protected from frost and direct sunlight |
| Shelf Life | 12 months from production in sealed, undamaged packaging |
Industry use cases
Ready-Mix Concrete
Central batching plants supplying sites 60 to 90 minutes away rely on it to deliver loads that still pump and place cleanly on arrival.
Infrastructure & Foundations
Rafts, pile caps and mat foundations poured continuously stay uniform in flow from the first truck to the last, avoiding cold joints.
High-Rise Construction
Long vertical pumping runs and staged placing benefit from a mix that holds workability through the full delivery cycle.
Hot-Weather Projects
Summer concreting across Delhi NCR and Pan-India sites gains a buffer against rapid slump loss driven by ambient heat.
Frequently asked questions
What is the difference between a slump retainer and a normal superplasticiser?
Will it delay the setting time of my concrete?
What dosage should I use?
Can it be added directly to cement or aggregate?
Does it meet Indian standards?
How is it packed and how should it be stored?
How we position Sika ViscoFlow-5263 NS
Within the Sika range, ViscoFlow-5263 NS is the slump-retention specialist; where you need aggressive water reduction and high early strength rather than long haul retention, look at Sika’s ViscoCrete high-range water reducers, and for shorter transit jobs the wider ViscoFlow family offers alternative retention grades. Space Arc pairs it with complementary Sika systems such as Sikament plasticisers for general workability and Sika curing compounds to protect the finished pour. Across our other brands we also stock equivalent PCE admixtures from Fosroc, MC-Bauchemie and Master Builders Solutions, so specifiers can match the admixture to the exact mix design and approval requirements on their project.
Fosroc Auramix 400 — A specifier standardised on the Fosroc admixture range may prefer Auramix 400, Fosroc’s PCE superplasticiser for self-compacting and pumped concrete with extended workability retention.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.