Fosroc Auramix 800
High-efficiency polycarboxylate-ether superplasticiser engineered for self-compacting concrete, flow concrete and high-strength low-water mixes.
What is it?
A high-range water-reducing (superplasticising) concrete admixture based on a modified high-efficiency polycarboxylate-ether (PCE) polymer, classified to EN 934-2 Table 3.1/3.2.
Where is it used?
Ready-mix and site concrete for self-compacting concrete (SCC), high-flow concrete, and high-strength low water/cement-ratio mixes across infrastructure, high-rise, precast and RMC plants.
Why use it?
Delivers very high water reduction (up to 40%), robust slump retention and strong cement dispersion, enabling dense, high-strength, durable and easily placed concrete with reduced segregation risk.
How is it applied?
Dosed into the concrete mix as a ready-to-use liquid, typically gauged with the mixing water at the batching plant or transit mixer; never added to dry cement or aggregate alone.
About Fosroc Auramix 800
Fosroc Auramix 800 is a high-efficiency superplasticising (high-range water-reducing) admixture formulated for the most demanding modern concrete: self-compacting concrete (SCC), high-flow concrete, and high-strength mixes that depend on a very low water content. It is built on a modified, high-efficiency polycarboxylate-ether (PCE) polymer whose long side chains dramatically improve cement dispersion, so the same workability is achieved with far less water — Fosroc states water reduction of up to 40% versus a comparable plain mix. Internationally it is classified to EN 934-2 Tables 3.1/3.2, the European specification for high-range water-reducing/superplasticising admixtures for concrete.
For Indian projects, this translates into a top-tier PCE that sits at the high-performance end of Fosroc’s Auramix superplasticiser family (above the Auramix 200/300/400/500 grades). It is the admixture you reach for when the brief is genuinely difficult: M50-and-above structural concrete, congested heavily-reinforced sections that must be filled without vibration, architectural fair-faced pours, or precast where early demoulding strength and surface finish matter. Because it is a liquid admixture rather than a coating or curing membrane, Auramix 800 is integral to the concrete itself — it modifies the fresh and hardened properties of the mix from the inside.
Space Arc Engineering supplies Fosroc Auramix 800 as an authorised Fosroc distributor across Delhi NCR and Pan-India, with technical back-up on trial mixes, dosage optimisation and compatibility checks for the specific cement and supplementary cementitious materials (fly ash, GGBS, silica fume) used on your project. The notes below are written to help engineers, consultants, architects and procurement teams specify and use the product correctly; always confirm the current batch-specific values against the latest Fosroc Technical Data Sheet (TDS) for your region before finalising a mix design.
The technical insight
The performance of Auramix 800 comes from polycarboxylate-ether (PCE) chemistry, which disperses cement very differently from older sulphonated naphthalene or melamine (SNF/SMF) superplasticisers. A PCE molecule has a charged backbone that adsorbs onto the cement grain and long, neutral polyethylene-oxide side chains that project outward; these side chains hold particles apart by steric (physical) hindrance rather than relying only on electrostatic repulsion. The practical result is a much higher water-reduction ceiling (Fosroc cites up to 40%) at lower dosage, plus better slump retention because the side-chain effect persists as hydration proceeds. Fosroc specifically markets Auramix 800 as a “robust” PCE that resists variations in mix water content and reduces the risk of post-plasticisation problems such as over-fluidity, bleeding or segregation when small water fluctuations occur on site — a real advantage for RMC where aggregate moisture varies through the day. For SCC, this dispersion efficiency is what lets the mix achieve self-levelling, self-compacting flow while keeping the water/cement ratio low enough to deliver high strength and low permeability. Because PCEs are sensitive to cement chemistry, C3A content and SCM type, the optimum dosage must be established by trial mix for each combination — the same dosage will not behave identically across two different cements.
Where it is used
- Self-compacting concrete (SCC) for congested, heavily-reinforced sections placed without vibration
- High-strength structural concrete (typically M50 and above) where a low water/cement ratio is critical
- High-flow / highly-workable pumped concrete for high-rise and long-distance placement
- Precast and prestressed concrete needing high early strength, fast demoulding and a fine surface finish
- Architectural and fair-faced concrete requiring a dense, blemish-free finish
- Durable concrete for marine, bridge, infrastructure and aggressive-exposure structures where low permeability is specified
- Ready-mix concrete (RMC) production needing robust workability retention despite minor water/moisture variation
Key advantages
- Very high water reduction (up to 40%), enabling high strength and low water/cement ratios
- Excellent cement dispersion producing self-compacting and high-flow concrete without segregation
- Robust formulation that tolerates minor variations in mix water content on site
- Reduced risk of post-plasticisation defects such as over-fluidity and bleeding
- Improves density, durability and reduces permeability of the hardened concrete
- Supports faster precast demoulding and better surface finish via efficient water reduction
- Classified to the international EN 934-2 T3.1/3.2 superplasticiser standard
- Typically chloride-free, suitable for reinforced and prestressed concrete (confirm on current TDS)
Limitations & considerations
- A high-performance PCE priced above general-purpose plasticisers; not cost-effective for ordinary low-grade concrete
- Overdosing can cause excessive flow, retardation, bleeding or segregation — strict dosing discipline is essential
- Performance is cement- and SCM-specific; mandatory trial mixes are needed for each material combination
- Not a curing compound, mould-release agent or repair product — it is a mix admixture only and must be combined with proper curing
- PCE admixtures can show variable compatibility with certain cements or with some older SNF-based admixtures — avoid uncontrolled mixing of admixture types
- Must be gauged accurately with the mixing water at the plant/mixer; not suitable for crude site addition
- Exact specific gravity, pH and chloride figures vary by region/batch and must be verified against the current Fosroc TDS
Selection & best practice
Establish the optimum dosage by laboratory and site trial mixes using the actual project cement, SCMs and aggregates, then hold to that dosage with calibrated dispensing equipment — small over-additions of a high-efficiency PCE can tip a mix into bleeding or segregation. Add Auramix 800 to the mixing water or to the wet concrete during mixing; never batch it directly onto dry cement or aggregate, and avoid combining it uncontrolled with naphthalene/melamine-based admixtures. For SCC, validate fresh properties (slump-flow, T500, V-funnel, L-box or J-ring as specified) on each trial. Store containers sealed, out of direct sun and protected from frost, and verify the in-date batch against its Fosroc Technical Data Sheet and Safety Data Sheet before use. Crucially, water reduction does not replace curing: protect and water-cure the placed concrete (or apply a Fosroc curing compound such as Concure) to realise the strength and durability the low w/c ratio makes possible.
Specifications
| Product type | High-range water-reducing / superplasticising concrete admixture |
| Chemical base | Modified high-efficiency polycarboxylate-ether (PCE) polymer |
| Standard classification | EN 934-2: Table 3.1/3.2 (high range water reducing / superplasticising admixture for concrete) |
| Primary function | Water reduction, cement dispersion, high-flow / self-compacting concrete |
| Water reduction | Up to 40% (manufacturer-stated, versus comparable plain mix) |
| Form | Ready-to-use liquid admixture |
| Chloride content | Typically chloride-free / nil (confirm on current Fosroc TDS) |
| Specific gravity | Approx. 1.05-1.10 at 25C, typical for PCE superplasticisers (verify against batch TDS) |
| Dosage | Trial-mix dependent; typical PCE range about 0.4-1.5 L per 100 kg cementitious material (confirm with Fosroc for the project mix) |
| Typical applications | SCC, high-flow concrete, high-strength low-w/c concrete, precast, RMC |
| Suitability | Reinforced and prestressed concrete (subject to chloride confirmation on TDS) |
| Storage | Keep sealed, out of direct sunlight and protected from frost; use within shelf life on TDS |
Industry use cases
High-rise & commercial buildings
Self-compacting and high-flow concrete for densely-reinforced columns, core walls and transfer slabs that must be filled completely without vibration, while keeping a low w/c ratio for M50+ strength.
Infrastructure & bridges
High-strength, low-permeability concrete for piers, decks and foundations in aggressive or marine exposure, where durability and reduced water ingress are specified.
Precast & prestressed yards
Efficient water reduction supports high early strength for faster demoulding cycle times and a dense, fair-faced surface finish on architectural and structural units.
Ready-mix concrete (RMC) plants
A robust PCE that holds workability despite day-to-day aggregate-moisture variation, reducing rejected loads and the need for retempering on site.
Architectural / fair-faced concrete
Enables flowing, self-levelling mixes that produce blemish-free, high-quality exposed surfaces without honeycombing.
Frequently asked questions
What is Fosroc Auramix 800 and what is it used for?
How much water can Auramix 800 reduce?
What is the correct dosage of Auramix 800?
Is Auramix 800 suitable for reinforced and prestressed concrete?
How does Auramix 800 differ from Auramix 200/300/400?
Does Auramix 800 replace curing?
How we position Fosroc Auramix 800
Within Fosroc’s Auramix superplasticiser family, Auramix 800 is the high-performance PCE option engineered specifically for SCC, high-flow and high-strength low-w/c concrete, positioned above the general-purpose and mid-range grades (Auramix 200, 300, 400, 500). On a typical project it pairs naturally with other Fosroc systems — a curing compound such as Concure to protect the placed concrete, Conplast WP/integral waterproofers where watertightness is needed, Renderoc/Conbextra for repair and grouting, and Auramix V200 viscosity-modifying agent where SCC stability needs extra control. Among competing high-range PCE superplasticisers an engineer might evaluate, credible alternatives in the Indian market include Sika ViscoCrete and Sika Plastiment, BASF/Master Builders Solutions MasterGlenium, Dr. Fixit (Pidilite) superplasticiser admixtures, and STP/other domestic admixture brands. These products are broadly comparable PCE/water-reducing chemistries; the right choice depends on the specific cement and SCM compatibility, target strength class, required flow/retention behaviour, local technical support and commercial terms — which is exactly where trial mixes and distributor back-up matter. Space Arc Engineering supplies and supports Fosroc Auramix 800 across Delhi NCR and Pan-India, and can advise objectively on the best fit for your mix design and project requirements.
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