Fosroc Auracast 404
A new-generation polycarboxylic ether superplasticiser engineered for the precast yard — high early strength, controlled workability retention and faster mould turnover.
What is it?
A high-performance, new-generation superplasticising admixture based on a polycarboxylic ether (PCE) polymer with long lateral chains, supplied as a light brown, instantly dispersible liquid for precast concrete.
Where is it used?
Precast and prestressed concrete plants producing segments, sleepers, piles, beams, girders, pipes and panels — plus high early-strength site pours where fast formwork or mould stripping is needed.
Why use it?
It cuts the water demand of flowable concrete through electrostatic dispersion, giving high early strength for rapid demoulding while holding moderate workability long enough to place and finish the mix.
How is it applied?
Added to the gauging water or the wet mix at the batching plant at roughly 0.3–2.0% by weight of cement; never dosed onto dry cement. Dosage is optimised by site trial against the actual mix, cement and ambient temperature.
About Fosroc Auracast 404
Fosroc Auracast 404 belongs to the Auracast range — Fosroc’s family of new-generation superplasticisers built specifically for the precast concrete industry. Where conventional naphthalene- or melamine-based admixtures disperse cement largely by charge repulsion, Auracast 404 uses a polycarboxylic ether (PCE) polymer with long lateral side chains. These side chains create both electrostatic and steric (physical spacing) separation between cement grains, releasing trapped mixing water and slashing the water demand of a flowable mix. The practical result for a casting yard is concrete that flows and compacts at a much lower water-to-cement ratio, which translates directly into higher strength at every age — and crucially, higher strength early.\n\nThat early-strength behaviour is the reason a precast manufacturer reaches for Auracast 404 rather than a general-purpose plasticiser. Precast economics are governed by mould turnover: the faster a unit reaches transfer or demoulding strength, the sooner the bed, mould or prestressing line is freed for the next cast. Auracast 404 is formulated to deliver high early strength while still providing moderate workability retention — enough open time to discharge, place, vibrate and finish without the slump collapsing prematurely. It is supplied as a light brown liquid that is instantly dispersible in water, so it blends cleanly at the batching plant without the lumping or settling seen with some powder or high-viscosity admixtures. As a Fosroc-authorised distributor and applicator covering Delhi NCR and Pan-India, Space Arc Engineering supplies Auracast 404 alongside technical support on dosage optimisation, mix compatibility and supplementary cementitious material (SCM) blends.
The technical insight
The defining mechanism is steric hindrance from the PCE comb-polymer architecture. The polymer backbone adsorbs onto the cement particle while the long lateral chains project outward, physically keeping adjacent grains apart for longer than charge repulsion alone can achieve. This is what lets Auracast 404 hold workability while still permitting a very low w/c ratio — the two properties that normally pull against each other. For precast, the formulation is biased toward early strength gain rather than the extended 2-hour-plus retention of a ready-mix/transit PCE, because precast concrete is placed within minutes of batching and the priority is rapid stiffening and strength development for fast demoulding. Practically, this means dosage is sensitive: PCE admixtures have a ‘saturation dosage’ beyond which extra admixture buys no more water reduction but can cause bleeding, segregation or retardation. Because PCEs are also more sensitive than older chemistries to cement chemistry, SCM type and fine-aggregate clay content, the correct working dosage must always be established by trial mix on the actual constituents rather than copied from another plant.
Where it is used
- High early-strength precast concrete for rapid mould and bed turnover
- Prestressed precast elements — sleepers, beams, hollow-core slabs and girders where early transfer strength is required
- Precast segments for metro, viaduct and tunnel-lining work
- Spun and cast concrete pipes, piles and poles
- High-performance and high-strength concrete (M40 and above) at low water-cement ratio
- Concrete incorporating SCMs such as fly ash, GGBFS and micro silica
- Site concrete where fast formwork stripping shortens construction cycles
Key advantages
- High early strength enables faster demoulding and quicker mould/bed reuse, improving plant productivity
- Strong water reduction at equal workability lifts strength at all ages and improves durability
- Moderate workability retention gives adequate open time to place, vibrate and finish precast units
- Lower water-cement ratio reduces drying shrinkage and shrinkage cracking and improves water impermeability
- Light brown liquid that is instantly dispersible in water — clean, consistent batching with no lumping
- Compatible with SCM-blended cements (fly ash, GGBFS, micro silica), supporting lower-carbon mix designs
- Helps achieve dense, low-permeability concrete with better resistance to carbonation and chloride ingress
Limitations & considerations
- Tuned for precast (high early strength, moderate retention) — not the right choice where very long slump retention is needed for transit/ready-mix; a retention-grade PCE such as Auramix is more suitable
- PCE chemistry is sensitive to overdosing: exceeding the saturation dose can cause bleeding, segregation or set retardation
- Performance varies with cement source, SCM type and aggregate fines/clay content, so a site trial mix is essential before production use
- Not a standalone air-entrainer, accelerator or corrosion inhibitor — pair with the appropriate dedicated admixture where those functions are required
- Should be added to gauging water or the wet mix, never directly onto dry cement
- Liquid admixture requiring protection from frost and direct sun; performance assumes correct storage within stated temperature range
Selection & best practice
Always establish the working dosage by trial mix on your actual cement, SCMs and aggregates rather than adopting a figure from another plant. Start near the lower end of the 0.3–2.0% (by weight of cement) range and increase in small steps until the target flow is reached at the lowest practical water content — stop once additional admixture no longer reduces water demand, as that is the saturation point. Dispense Auracast 404 into the gauging water or onto the wet mix during batching, never onto dry cement, and keep dosing equipment calibrated because PCEs act at low volumes. Run early-age strength checks (e.g. transfer/demould strength) under your real curing regime to confirm turnover times before committing to production. Store drums under cover, out of direct sun and protected from frost, and observe the stated shelf life. For prestressed and reinforced precast, confirm the chloride class against the current product TDS for the India market. When in doubt on compatibility or dosage, ask Space Arc Engineering for a trial-mix recommendation.
Specifications
| Product type | New-generation high-range water-reducing superplasticiser (admixture) |
| Chemical base | Polycarboxylic ether (PCE) polymer with long lateral chains |
| Primary action | Electrostatic + steric dispersion of cement, reducing water demand of flowable concrete |
| Appearance / colour | Light brown liquid, instantly dispersible in water |
| Specific gravity (family-typical, confirm on India TDS) | approx. 1.05–1.09 @ 25°C (Auracast 4xx PCE range) |
| Recommended dosage (family-typical) | approx. 0.3–2.0% by weight of cement / total binder; optimise by trial |
| Workability retention | Moderate — tuned for precast / high early strength |
| Chloride content | Low / chloride-class per current product TDS; Auracast PCE range supplied for prestressed & reinforced concrete (verify value for the India market) |
| Conformity (range) | Auracast precast PCE admixtures conform to IS 9103 and ASTM C494 (Type F high-range water reducer; Type G where applicable) / BS EN 934-2 — confirm classification on the product-specific TDS |
| Pack sizes (family-typical) | Drums (e.g. 20 kg & 200 kg) and bulk supply — confirm current India packs |
| Shelf life (family-typical) | approx. 12 months in original sealed containers, stored out of direct sun and frost |
| Best for | High early-strength precast / prestressed concrete with moderate workability retention |
Industry use cases
Precast & prestressed manufacturing
Sleepers, hollow-core slabs, beams and girders cast at low w/c so units reach transfer/demould strength quickly, freeing prestressing beds and moulds for the next cycle.
Metro & infrastructure precast
Tunnel-lining and viaduct segments needing high early strength, dimensional accuracy and dense, low-permeability concrete for long-term durability.
Concrete pipes, piles & poles
Spun and cast products where rapid early strength supports demoulding and de-tensioning, and a low w/c improves crack resistance and water-tightness.
High-strength structural concrete
M40+ precast and site concrete where strong water reduction at workable consistency delivers the target grade without raising cement content.
Lower-carbon SCM mixes
Concrete blended with fly ash, GGBFS or micro silica, where Auracast 404 maintains workability at reduced water content to support durable, lower-clinker mixes.
Fast-cycle site casting
In-situ pours where quicker formwork stripping shortens the construction programme without compromising strength.
Frequently asked questions
What is Fosroc Auracast 404 and what is it used for?
How does it differ from a naphthalene-based superplasticiser like Conplast?
What dosage should I use?
Is Auracast 404 suitable for prestressed and reinforced concrete?
Which standards does it conform to?
How is it different from Fosroc Auramix or Auracast 405?
How should Auracast 404 be stored and handled?
How we position Fosroc Auracast 404
Within the Fosroc admixture portfolio, Auracast 404 sits in the precast-focused Auracast PCE family alongside Auracast 405, 270M, 280 and 295 — products chosen when high early strength and fast mould turnover matter more than long slump life. Where a project needs extended workability retention for ready-mix or transit concrete, Fosroc’s Auramix range (e.g. Auramix 350/400/500) is the better fit, and for general site work the older naphthalene-based Conplast SP430/SP500 plasticisers remain a cost-effective option. Against the wider market, credible alternatives include Sika’s ViscoCrete PCE superplasticiser range, Master Builders Solutions (MBS) MasterGlenium, and the admixture lines from STP and Dr. Fixit (Pidilite); the right selection depends on local cement compatibility, the chloride class required and the early-strength target. Space Arc Engineering supplies Auracast 404 as an authorised Fosroc distributor and applicator across Delhi NCR and Pan-India, and can run a trial-mix recommendation to confirm dosage and compatibility before you commit to production.
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