Sika ViscoCrete-735 PR
A third-generation polycarboxylate ether superplasticizer that pulls water out of the mix without stealing workability, giving you dense, high-strength, low-permeability concrete for RMC, precast and self-compacting pours.
What is it?
A third-generation high-range water reducer based on modified polycarboxylate (PCE) chemistry, supplied as a chloride-free brown liquid for concrete and mortar.
Where is it used?
Ready-mix plants, precast yards, site-batched pours and self-compacting concrete across reinforced and prestressed structures.
Why use it?
It cuts water demand sharply so the same slump is reached at a lower w/c ratio, lifting strength and durability while keeping the mix easy to place and compact.
How is it applied?
Dosed at 0.2-2.0% by weight of cementitious material into the mixing water or after 50-70% of the water is in the mixer, with a minimum 60-second wet mix.
About Sika ViscoCrete-735 PR
Sika ViscoCrete-735 PR is Sika’s third-generation superplasticizer built on modified polycarboxylate ether chemistry, and it sits at the workhorse end of the ViscoCrete range for Indian ready-mix and precast production. Supplied as a brown liquid at roughly 1.12 kg/l, it is completely chloride-free, so there is nothing in the formulation that would drive corrosion of embedded steel. That makes it equally at home in ordinary RCC and in the more demanding world of prestressed and precast members, where reinforcement protection is non-negotiable. It complies with IS 9103 and ASTM C494, the two standards most Indian consultants and clients will ask to see on a mix submittal.
The reason engineers reach for a PCE admixture like this one is control. Concrete strength and durability are governed largely by the water-to-cement ratio, but you still need a mix that can actually be poured, pumped and compacted on site. ViscoCrete-735 PR breaks that trade-off: it lets a batching plant hold a low w/c ratio while the fresh concrete stays fluid and cohesive. The result is a denser, less permeable matrix that resists water ingress and aggressive media, with better shrinkage and creep behaviour over the life of the structure. For a contractor, that translates into fewer honeycombs, cleaner precast finishes and mixes that place predictably even in congested reinforcement.
The technical insight
The admixture works through a physical mechanism rather than a chemical reaction with the cement. Its long-chain polycarboxylate molecules adsorb onto the surface of cement grains, and the side chains that project outward create a steric (physical spacing) barrier that keeps particles from clumping together. Conventional naphthalene-based plasticizers rely mainly on electrostatic repulsion, which fades as the mix ages; PCE steric hindrance is more durable and far more efficient, which is why a third-generation product can achieve powerful water reduction at modest dosages. In practice, deflocculating the cement releases the water that would otherwise be trapped between agglomerated grains, so you can either add far less water for the same slump, or hold the water constant for a much more fluid, self-levelling mix. Because the effect is dispersion-driven, performance is sensitive to cement chemistry and fines content, which is exactly why Sika insists dosage be fixed by site trials rather than a fixed rule of thumb.
Where it is used
- Ready-mix concrete production where consistent slump and strength are needed batch after batch
- Precast concrete elements requiring high early strength and clean, blemish-free demoulded finishes
- Site-batched structural concrete for columns, rafts and slabs
- Self-compacting concrete (SCC) for heavily reinforced or complex formwork with no vibration
- High-strength grades (M40 and above) that depend on a low water-cement ratio
- Reinforced and prestressed structures where a chloride-free admixture is mandatory
- Durable concrete for water-retaining and marine-exposed structures needing low permeability
- Pumped concrete over distance or height where flowability and cohesion both matter
Key advantages
- Powerful water reduction that raises compressive strength and cuts permeability at the same slump
- Chloride-free formulation, safe for reinforced and prestressed steel
- Excellent plasticizing action for easier placing, pumping and compaction
- Improved long-term shrinkage and creep behaviour in hardened concrete
- Compatible with all cement types and blendable with many other Sika admixtures
- Complies with IS 9103 and ASTM C494, simplifying mix approvals with consultants
- Enables self-compacting mixes that place in congested sections without vibration
- Wide dosage window (0.2-2.0%) allowing mixes to be tuned from firm to highly flowable
Limitations & considerations
- Overdosing or adding extra water on top of the admixture can trigger bleeding or segregation
- Optimum dosage is not fixed and must be established by site trials for each mix and cement
- Performance varies with cement chemistry, fines and ambient temperature, so lab results need field confirmation
- Should not be added to dry aggregate or cement; it must go into the water or a wetted mix
- If frozen or precipitated it needs slow thawing at room temperature and intensive re-mixing before use
- As a dispersant it controls water demand and workability but does not accelerate set or provide extended retardation on its own
Selection & best practice
Fix the dosage by trial batch, not by catalogue figure. Start near the middle of the 0.2-2.0% by-weight-of-cementitious range and adjust to hit your target slump or flow at the design water-cement ratio. Add the admixture into the mixing water, or into the mixer once 50-70% of the water is already in; never dose it onto dry cement or aggregate. Stir the drum well before drawing product, and allow a minimum 60-second wet mixing time so the polymer fully disperses the binder. Resist the temptation to add more water to loosen a stiff mix once the admixture is in; that is what causes bleeding and segregation. Store drums in the shade between +10C and +40C, away from frost, and use within the 12-month shelf life. In cold spells, keep drums from freezing; if precipitation has occurred, thaw slowly and mix intensively before dispensing.
Specifications
| Product type | Third-generation PCE high-range water reducer / superplasticizer |
| Chemical base | Aqueous solution of modified polycarboxylate |
| Appearance / colour | Brown liquid |
| Density | ~1.12 kg/l at 25°C |
| pH value | ≥ 6 |
| Recommended dosage | 0.2-2.0% by weight of cementitious material |
| Standards | IS 9103, ASTM C494 |
| Packaging | 255 kg HDPE drum / bulk supply |
| Shelf life & storage | 12 months; store dry at +10°C to +40°C, protect from sunlight and frost |
Industry use cases
Ready-Mix Concrete
Holds a uniform, low water-cement ratio across every batch so RMC plants deliver consistent strength and pumpable slump to site.
Precast & Prestressed
Chloride-free chemistry protects tensioned strands while high early strength speeds demoulding and turnover in precast yards.
Infrastructure & Bridges
Produces dense, low-permeability structural concrete that resists water and aggressive ingress in piers, decks and retaining works.
High-Rise & Commercial
Enables self-compacting mixes that fill heavily reinforced columns and walls cleanly without vibration in tight formwork.
Water-Retaining Structures
Reduced permeability and improved shrinkage behaviour suit tanks, treatment plants and basements where watertightness is critical.
Frequently asked questions
Is Sika ViscoCrete-735 PR the same as a normal plasticizer?
What dosage should I use?
Does it contain chlorides or affect reinforcement?
Can I use it for self-compacting concrete?
How is it added to the mix?
What pack size does it come in and how long does it keep?
How we position Sika ViscoCrete-735 PR
Within the Sika ViscoCrete family, the 735 PR is the general-purpose water-reducing workhorse; specifiers needing longer slump retention for extended haul or hot-weather pumping often step up to Sika ViscoCrete-730 PR, 753 PR or 755 PR, while set control is handled by companion products like SikaSet and Plastiment retarders. If you are standardising a plant on one supplier, we also carry equivalent PCE superplasticizers from other brands we distribute, such as Fosroc Auramix, MC-Bauchemie MC-PowerFlow and Master Builders Solutions MasterGlenium. As an authorised distributor and applicator across Delhi NCR and Pan-India, Space Arc can help you trial-match the right admixture to your cement and mix design rather than defaulting to a single SKU.
Fosroc Auramix 400 — A specifier already standardised on Fosroc admixtures may prefer Auramix 400, a comparable PCE superplasticizer 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.