Fosroc Structuro 480
A high-performance cohesion agent that gives self-compacting concrete its stability — controlling bleed, segregation and sedimentation so highly fluid mixes flow and place by gravity without honeycombing.
What is it?
Fosroc Structuro 480 is a liquid cohesion agent — a viscosity-modifying admixture (VMA) — that thickens the paste phase of highly fluid concrete so it stays homogeneous while still flowing freely.
Where is it used?
Self-compacting concrete (SCC) for heavily reinforced walls and columns, prefabrication units, architectural fair-faced concrete, industrial floor slabs, and ultra-fine binder grouts on building and infrastructure projects across India.
Why use it?
It lets you run the very high water-reducer dosages SCC needs without the mix bleeding or segregating — so aggregate stays suspended, the surface finishes clean, and steel is fully encased without vibration.
How is it applied?
Dosed at 1.0-4.0 litre/m3 and added to the concrete with the mixing water (or into the ready-mix truck via dosing pump), then blended at high speed for at least two minutes alongside a Structuro/Auramix superplasticiser.
About Fosroc Structuro 480
Fosroc Structuro 480 belongs to the Structuro family of concrete admixtures, but it plays a very specific and often misunderstood role. It is not a plasticiser or a water-reducer — it is a cohesion agent, the technical term being a viscosity-modifying admixture (VMA). Where a superplasticiser makes concrete flow, a VMA controls how that flow behaves. In a self-compacting concrete (SCC) mix, the cement paste is pushed to very high fluidity, and at that point the natural tendency of the mix is to fall apart: water rises to the surface (bleed), the heavier coarse aggregate sinks (sedimentation), and the mortar separates from the stone (segregation). Structuro 480 is engineered to counteract exactly these failure modes by increasing the viscosity and stability of the paste phase, so the fluid concrete behaves as a single homogeneous fluid rather than a suspension that wants to separate.
The official Fosroc description is direct about this purpose: it is a “high performance cohesion agent specially designed to ensure a good consistency and stability in concrete with very high fluidity,” particularly adapted to the production of self-compacting concrete. The result, in practical terms, is concrete that can be poured and placed by gravity alone — flowing into and around dense reinforcement, filling formwork completely, and finishing with a clean facing, all without poker vibration.
For Indian site conditions this matters more than it might first appear. SCC adoption in India has grown steadily on metro projects, high-rise cores, precast yards and architectural concrete work, but local materials — variable sand gradings, manufactured sand with high fines, and inconsistent aggregate moisture — make SCC notoriously sensitive. A mix that is perfectly balanced in a lab can bleed or segregate on site when the sand changes or the ambient temperature climbs. A robustness-enhancing VMA like Structuro 480 widens the working window: it gives the mix design tolerance to small batching variations, so the SCC stays stable across a working day rather than only under ideal conditions. That robustness is the real reason cohesion agents are specified, and it is why Structuro 480 sits in a different toolbox from the better-known Conplast water-reducers.
As an authorised Fosroc distributor serving Delhi NCR and pan-India, Space Arc Engineering positions Structuro 480 as a specialist component of an SCC system rather than a standalone product. It is almost always paired with a high-range superplasticiser (from the Structuro or Auramix ranges) and a carefully proportioned mix design — the superplasticiser delivers flow, Structuro 480 delivers stability, and together they make true self-compacting concrete reliable on site.
The technical insight
The defining behaviour of a cohesion agent like Structuro 480 is that it modifies the rheology of fresh concrete asymmetrically. Self-compacting concrete must satisfy two competing demands at once: it has to flow freely under its own weight (low yield stress, achieved by the superplasticiser) yet resist the aggregate settling out (adequate plastic viscosity and yield-stress recovery at rest). A water-reducer alone tends to push a mix toward low viscosity and low yield stress — great for flow, but the point at which it flows easily is uncomfortably close to the point at which it segregates. Structuro 480 raises the viscosity and stability of the paste so the mix holds aggregate in suspension at rest, while the polymer system still allows the concrete to shear-thin and flow when poured. This is the rheological balancing act at the heart of SCC, and it is why the two admixtures are dosed together rather than one substituting for the other. A useful field consequence: a robust VMA reduces the mix’s sensitivity to small changes in water content and sand fines — a few extra litres of water in a batch that would tip a VMA-free SCC into bleeding can be tolerated when Structuro 480 is present, because the cohesion agent buffers the loss of stability. The verified specific gravity of roughly 1.01 confirms it is a low-solids, largely water-based liquid system added in small volumetric doses, and the recommendation to blend at high speed for at least two minutes reflects that the polymer needs full dispersion through the paste to develop its viscosity-building effect uniformly.
Where it is used
- Self-compacting concrete (SCC) for heavily congested reinforcement where vibration is impractical
- High-density reinforced walls, shear walls and slender columns
- Precast and prefabrication yards producing dimensionally accurate, blemish-free units
- Architectural and fair-faced concrete requiring a clean, uniform surface finish
- Industrial floor slabs placed as flowing, self-levelling concrete
- Ultra-fine binder-based grouts requiring stability against bleed and segregation
- Building construction and infrastructure pours where placement is by gravity rather than poker vibration
Key advantages
- Produces stable self-compacting concrete that places by gravity, eliminating the need for poker vibration
- Directly opposes bleeding, segregation and sedimentation, keeping the mix homogeneous from batching to placement
- Holds coarse aggregate in suspension so the hardened concrete is uniform top to bottom
- Delivers a clean, well-finished facing — valuable for architectural and exposed concrete
- Improves the robustness of the SCC mix, widening tolerance to normal site variations in sand and water
- Compatible with all Portland cements, SRC cements and cement replacement materials (PFA, GGBFS, microsilica)
- Works alongside other Fosroc admixtures (superplasticisers) in the same mix when dosed separately
- Convenient low dosage (1.0-4.0 litre/m3) measured and added with the mixing water
Limitations & considerations
- It is a cohesion agent, not a water-reducer — it does not by itself make concrete flow and must be paired with a superplasticiser to produce SCC
- Designed for highly fluid / self-compacting mixes; it offers no benefit in conventional vibrated concrete of normal workability
- Over-dosing can make the mix too viscous (sticky), reducing flowability and making placement and finishing harder
- Final SCC performance depends heavily on mix design and local aggregate gradation — the admixture cannot fully correct a poorly proportioned mix
- Should be added separately to the mix, not pre-blended with other admixtures in the same container
- Requires adequate high-speed mixing (at least two minutes) for the polymer to disperse and develop its effect uniformly
- Trial mixes with the actual project materials are essential before site supply, as SCC is sensitive to sand fines and moisture
Selection & best practice
Treat Structuro 480 as one half of a two-part SCC system, never as a drop-in additive. Begin with laboratory and site trial mixes using the project’s actual cement, sand, aggregate and any PFA/GGBFS/microsilica, and tune the superplasticiser dosage for the target flow first, then add Structuro 480 within the 1.0-4.0 litre/m3 band to dial in stability — use the lower end for slabs and higher fluidity, and around 2.0-3.0 litre/m3 for vertical members where a clean facing matters. Add the measured dose to the concrete with the mixing water (or into the ready-mix truck via a calibrated dosing pump), keep it separate from other admixtures, and mix at high speed for at least two minutes to fully disperse the polymer. Validate every trial with standard SCC fresh-property tests — slump flow, T500, J-ring or L-box for passing ability, and a visual or sieve segregation check — and re-trial whenever the sand source or fines content changes. Store drums in cool, shaded conditions and use within the 12-month shelf life.
Specifications
| Product type | Cohesion agent / viscosity-modifying admixture (VMA) for self-compacting concrete |
| Appearance | Opaque liquid |
| Specific gravity | Approx. 1.01 |
| Dosage range | 1.0 to 4.0 litre per m3 of concrete (typically 2.0-3.0 litre/m3 for vertical members) |
| Cement compatibility | All Portland cements, SRC cements; cement replacements PFA, GGBFS and microsilica |
| Admixture compatibility | Compatible with other Fosroc admixtures in the same mix (added separately) |
| Mixing | Add with mixing water; blend at high speed for at least 2 minutes |
| Packaging | 200 litre drums |
| Shelf life | 12 months in original sealed packaging |
| Primary use | Self-compacting concrete, prefabrication, industrial slabs, high-density reinforced walls, ultra-fine binder grouts |
Industry use cases
Precast & prefabrication
In precast yards, Structuro 480 stabilises high-flow SCC so units fill complex moulds completely around dense reinforcement and demould with sharp arrises and a blemish-free surface, reducing rejects and surface repair.
High-rise & infrastructure cores
For shear walls, lift cores and slender columns with congested rebar, the cohesion agent lets SCC place by gravity through tight reinforcement without vibration, ensuring full steel encasement in members where a poker simply cannot reach.
Architectural / fair-faced concrete
On exposed and architectural concrete, controlling bleed and segregation is what delivers a uniform, well-finished facing — Structuro 480 keeps the paste stable so the surface is consistent without colour banding or aggregate streaking.
Industrial flooring
For large industrial slabs poured as flowing self-levelling concrete, the admixture suppresses surface bleed and aggregate settlement, helping achieve a flat, dense, uniform slab section.
Specialist grouting
In ultra-fine binder-based grouts that must remain highly fluid, Structuro 480 prevents sedimentation and bleed so the grout stays stable and homogeneous during placement.
Frequently asked questions
Is Fosroc Structuro 480 a water-reducer or superplasticiser?
What is the correct dosage for Structuro 480?
How is Structuro 480 added to the mix?
Is Structuro 480 compatible with fly ash and GGBFS mixes?
Does Structuro 480 eliminate the need for vibration?
How should Structuro 480 be stored and what is its shelf life?
How we position Fosroc Structuro 480
Within the Fosroc range, Structuro 480 is a specialist cohesion agent and should be understood by contrast with the better-known water-reducers and superplasticisers it works alongside. Fosroc Conplast SP430 and the Structuro/Auramix superplasticiser families create the flow in an SCC mix, while Structuro 480 supplies the stability — they are complementary, not interchangeable. Other Structuro grades (such as the self-compacting superplasticisers Structuro 311 and 351) overlap on the SCC application but deliver flow rather than cohesion, so the right specification often combines a Structuro superplasticiser with the Structuro 480 cohesion agent. For integral waterproofing of concrete a different product set applies — Fosroc Conplast Crystalline or Conplast WP90 — so Structuro 480 should not be confused with a waterproofing admixture despite some distributor listings labelling it that way. Among competing brands, the direct equivalents are viscosity-modifying / cohesion admixtures: Sika offers Sika Stabilizer and SikaViscoCrete-based SCC systems, BASF/Master Builders Solutions (MBS) offers MasterMatrix VMAs, and STP and Dr. Fixit address adjacent admixture needs though their published ranges centre more on waterproofing and general plasticisers than on dedicated SCC cohesion agents. The honest selection guidance: if your goal is self-compacting concrete with reliable robustness on Indian sites, specify a superplasticiser plus a VMA together — Structuro 480 is Fosroc’s purpose-built cohesion agent for that role, and Space Arc Engineering supplies it as part of a matched SCC system rather than in isolation.
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