Fosroc Structuro 335
High-performance polycarboxylic-ether (PCE) superplasticiser for high-strength, high-workability and self-compacting concrete — ASTM C494 Type F and Type D compliant.
What is it?
A new-generation high-range water-reducing superplasticiser based on polycarboxylic-ether (PCE) polymer technology, supplied as a liquid admixture for ready-mix, precast and site-batched concrete.
Where is it used?
High-grade structural concrete, precast and prestressed elements, self-compacting concrete (SCC), pumped and hot-weather concreting across Delhi NCR and Pan-India projects served by Space Arc Engineering.
Why use it?
Delivers high early and ultimate compressive strength, strong water reduction, controlled set retardation and excellent flow — letting producers cut water/cement ratio, save cement and improve durability without mechanical vibration.
How is it applied?
Dosed at 0.5-2.0% by weight of cement/cementitious content, added to the mixer with the gauging water through a recommended dispenser; optimum dosage confirmed by site trials.
About Fosroc Structuro 335
Fosroc Structuro 335 is a high-performance concrete superplasticiser built on polycarboxylic-ether (PCE) polymer chemistry, positioned for applications where increased early strength and high ultimate compressive strength are essential. Unlike older naphthalene- and lignosulphonate-based plasticisers that rely purely on electrostatic dispersion, Structuro 335 uses a carboxylic-ether polymer with long lateral side chains that work through a steric (physical spacing) mechanism. The result is far more efficient cement-particle dispersion at low dosage, giving concrete that flows readily while still allowing a low water/cement ratio. For Indian producers this translates into a practical dual benefit: the same workability with less water (and therefore higher strength), or the same strength with less cement (and therefore lower cost per cubic metre). The admixture also enhances the cohesiveness of the cement and aggregate matrix, which directly improves the durability of the hardened concrete. Fosroc supplies the product as a ready-to-use liquid that is added directly to the mixer, ideally at the same time as the mixing water. Structuro 335 carries no intentionally added calcium chloride, making it suitable for reinforced and prestressed work where chloride-induced corrosion of steel is a concern. Space Arc Engineering, an authorised Fosroc distributor operating across Delhi NCR and Pan-India, stocks and supplies Structuro 335 to ready-mix plants, precast yards and infrastructure contractors, backing supply with application guidance and the wider Fosroc admixture and repair range.
The technical insight
The defining feature of Structuro 335 is its PCE backbone with long grafted side chains. When the polymer adsorbs onto cement grains, the side chains project outward and create a steric barrier that physically keeps particles apart, releasing the water otherwise trapped in flocculated cement clusters. This is fundamentally more powerful and longer-lasting than the charge-repulsion of sulphonated-naphthalene-formaldehyde (SNF) admixtures, which is why a small dosage of Structuro 335 produces both high flow and substantial water reduction. Per the Fosroc TDS, it is classified to ASTM C494 as both Type F (high-range water-reducing) and Type D (water-reducing and retarding), meaning it combines plasticising action with a degree of controlled set retardation that extends the placing window — valuable for pumping over distance and for hot-weather concreting in the Indian climate. The product is engineered for modern aggregate realities: it is fully compatible with mixes using up to 100% manufactured (crushed) sand combined with natural or silica sand, and works with all types of Portland cement as well as PFA (fly ash) and ground slag blends. One critical chemistry caveat the TDS makes explicit is that Structuro 335 is NOT compatible with naphthalene-based admixtures — PCE and SNF polymers should never be blended or layered in the same mix, as the interaction can cause unpredictable slump loss or set behaviour.
Where it is used
- High-grade structural concrete (M30 and above) where high early and ultimate compressive strength is specified
- Self-compacting and high-flow concrete that places without mechanical vibration, reducing noise and labour
- Precast and prestressed concrete elements requiring low w/c ratio, high early strength and superior surface finish
- Pumped concrete needing extended placing time and retained workability over long delivery routes
- Hot-weather concreting where controlled retardation prevents premature stiffening
- Durable, dense concrete for water-retaining and water-resisting structures
- Ready-mix concrete production using up to 100% manufactured sand and PFA/GGBS blended cements
Key advantages
- Increased early strength enabling faster formwork stripping and precast demoulding cycles
- Increased ultimate compressive strength for higher-grade, more durable concrete
- Controlled retardation of set that extends placing time, ideal for pumping and hot weather
- High water reduction allowing a low w/c ratio without sacrificing workability
- Saves cement without loss in strength, lowering mix cost per cubic metre
- Higher density giving improved durability and resistance to water penetration
- Allows production of self-compacting concrete, eliminating mechanical vibration and its noise
- No intentionally added calcium chloride — suited to reinforced and prestressed concrete
- Compatible with 100% manufactured sand, all Portland cements, PFA and ground slag
Limitations & considerations
- NOT compatible with naphthalene (SNF) based admixtures — must not be combined in the same mix
- Overdosing (roughly double the recommended rate) can cause excessive set retardation and may lower early strength, though ultimate strength is preserved if good curing is maintained
- Optimum dosage must be established by site trials; it cannot be fixed by a single number across all mixes, cements and aggregates
- Performance and set times are sensitive to cement type and ambient temperature, requiring trial verification
- Shelf life of 12 months applies only in closed original containers at 20-35 degrees C; higher storage temperatures can shorten it
- Mildly irritant to skin and eyes — requires standard PPE during handling
- Requires a recommended dispenser and correct addition with the gauging water for consistent results
Selection & best practice
Always begin with laboratory and site trials to fix the optimum dosage within the 0.5-2.0% by weight of cement range, adjusting for your specific cement, sand type and the degree of retardation required. Add Structuro 335 directly to the mixer through a recommended dispenser, preferably at the same time as the gauging water, and never pre-mix it with naphthalene-based admixtures. In hot Indian summers, exploit the Type D retarding action to maintain workability during transit and pumping, but guard against overdosing, which can excessively delay set. Pair placement with proper curing — Fosroc recommends the CONCURE curing membrane or an equivalent good curing regime — to realise the full early- and ultimate-strength benefit. Store drums sealed in shade between 20-35 degrees C and use within the 12-month shelf life.
Specifications
| Product type | High-range water-reducing superplasticiser (PCE) |
| Chemical base | Polycarboxylic-ether (carboxylic ether polymer) technology |
| Standards compliance | ASTM C494 Type F and Type D |
| Specific gravity | 1.08 – 1.10 at 23 +/- 3 degrees C |
| Chloride content | No intentionally added calcium chloride |
| Recommended dosage | 0.5% – 2.0% by weight of cement/cementitious content |
| Cement compatibility | All Portland cements; PFA and ground slag blends; up to 100% manufactured sand |
| Incompatibility | Not compatible with naphthalene-based admixtures |
| Dispensing | Add to mixer via recommended dispenser, preferably with the mixing water |
| Packaging | 210 litre drum or 1000 litre bulk |
| Shelf life | 12 months in closed original container at 20 – 35 degrees C |
| Health & fire | Non-toxic, non-flammable; skin/eye irritant — use PPE |
Industry use cases
Ready-Mix Concrete (RMC)
RMC plants in Delhi NCR use Structuro 335 to hold workability during transit and pumping while cutting w/c ratio, producing consistent M30+ concrete with manufactured-sand and fly-ash blends.
Precast & Prestressed Manufacturing
Precast yards exploit the high early strength and superior surface finish to accelerate demoulding and bed turnover, and the low chloride profile suits prestressed strands.
Infrastructure & Bridges
High-density, low-permeability concrete for piers, decks and substructures benefits from the durability and water-penetration resistance Structuro 335 imparts.
High-Rise & Commercial Buildings
Self-compacting concrete for heavily reinforced columns, core walls and rafts places without vibration, improving compaction in congested sections and reducing site noise.
Water-Retaining Structures
Tanks, STPs and reservoirs use the increased density and resistance to water penetration to achieve durable, low-permeability concrete.
Frequently asked questions
Is Fosroc Structuro 335 a real Fosroc product?
What is the recommended dosage of Structuro 335?
Which standards does Structuro 335 comply with?
Can Structuro 335 be mixed with other admixtures?
What happens if Structuro 335 is overdosed?
How is Structuro 335 packaged and stored, and where can I buy it in India?
How we position Fosroc Structuro 335
Structuro 335 sits at the high-performance end of Fosroc’s admixture range, using modern PCE chemistry rather than the older sulphonated-naphthalene technology of Fosroc’s widely-used Conplast SP430. Where Conplast SP430 (SNF-based, to BS 5075 Part 3 and IS 9103) remains a reliable, cost-effective workhorse for general flowing and high-strength concrete, Structuro 335 is the choice when superior dispersion, lower dosage, self-compacting performance and finer surface finish justify a PCE admixture — and the two should never be blended, as PCE and SNF are incompatible. Within the broader Indian market, Structuro 335 competes with PCE superplasticisers such as Sika ViscoCrete, BASF/Master Builders Solutions MasterGlenium, and the high-range ranges from STP and Dr. Fixit (Pidilite); selection between brands typically comes down to local technical support, trial results with the specific cement and aggregates, and supply reliability. For Indian projects, Space Arc Engineering positions Structuro 335 as the premium Fosroc option for RMC, precast and SCC work, complemented by Fosroc repair, grouting and curing products (such as CONCURE membranes) to deliver a complete concrete solution from a single authorised source.
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