Fosroc Auracast 270
A new-generation polycarboxylic-ether (PCE) superplasticiser engineered for precast and prestressed concrete where high early strength, low water-cement ratio and a clean demoulded finish matter most.
What is it?
A high-range water-reducing admixture (superplasticiser) based on a polycarboxylic-ether polymer with long lateral side chains, supplied as a light-brown to pale-yellow liquid that disperses instantly in the mix water.
Where is it used?
Precast and prestressed yards, concrete pipe and segment plants, and high-performance ready-mix where high early strength and tight w/c ratios are specified — widely used across precast operations in Delhi NCR and pan-India.
Why use it?
It cuts water demand sharply through an electrostatic + steric dispersion mechanism, delivering high 16-24 hour strengths for faster demoulding and bed turnover without raising cement content, while holding workability longer than older naphthalene superplasticisers.
How is it applied?
Dosed at 0.3-1.5% by weight of cementitious content, added to the gauging water or at the end of the batching cycle; never added to dry aggregate. Trial mixes establish the optimum dose for each combination of cement, fly ash, GGBFS or microsilica.
About Fosroc Auracast 270
Fosroc Auracast 270 — marketed in India as Auracast 270M — is a new-generation superplasticising concrete admixture built around a polycarboxylic-ether (PCE) polymer carrying long lateral side chains. Unlike the older sulphonated naphthalene (SNF) and melamine superplasticisers that work mainly by surface charge, the PCE backbone in Auracast 270 disperses cement grains by a combination of electrostatic repulsion and steric (physical) hindrance from those side chains. The practical result is a dramatic reduction in water demand at a given workability, which is exactly what a precaster needs to push compressive strengths up and demoulding times down.
The product is supplied as a light-brown to pale-yellow liquid that is instantly dispersible in water, making it easy to introduce into a busy batching cycle. It was developed specifically for the precast and prestressed concrete sector, where the commercial reality is bed turnover: the faster a unit reaches lifting and transfer strength, the more units a casting bed produces per day. Auracast 270 is designed to deliver high 16-24 hour strengths from a low water-cement ratio mix while still giving the placing crew enough open time to compact and finish a clean, blowhole-free face.
For Indian projects this sits within Fosroc’s Auracast precast family — alongside Auracast 200, 280 and the Auramix ready-mix range — and complies with IS 9103:1999 for superplasticising admixtures and ASTM C494 as a Type F (high-range water reducer) or Type G (high-range water reducer and retarder) depending on dosage. Space Arc Engineering supplies and supports the product as an authorised Fosroc distributor and applicator across Delhi NCR and pan-India, with trial-mix guidance for the specific cements and supplementary cementitious materials used on site.
The technical insight
The engineering value of Auracast 270 lies in the side-chain architecture of its PCE molecule. The carboxylate backbone anchors onto positively charged sites on hydrating cement particles, while the long polyethylene-oxide side chains project outward and physically keep adjacent grains apart. This steric effect is far more robust against early hydration than the purely electrostatic action of naphthalene-based plasticisers, which is why Auracast 270 reduces the rapid slump loss normally associated with high-range water reducers. In precast terms, a low-viscosity, self-levelling mix can be carried from batching to placing without the workability collapsing before the unit is filled.
By enabling water-cement ratios well below what a control mix tolerates, the admixture builds a denser, lower-permeability matrix. That translates directly into higher early and ultimate strength, reduced drying shrinkage and creep, improved resistance to carbonation and chloride ingress, and a more durable cover zone protecting the reinforcement. The low-viscosity character is deliberately tuned for precast plant — it flows and compacts readily around congested prestressing strand and intricate moulds, releasing entrapped air to give the sharp arrises and smooth fair-faced finish that architectural precast demands. The admixture is also formulated to perform in blended systems containing fly ash, GGBFS or microsilica, so it suits the lower-clinker, durability-led mix designs now common in Indian infrastructure work.
Where it is used
- High-early-strength precast concrete elements requiring rapid demoulding and casting-bed turnover
- Prestressed and pretensioned concrete — beams, holl-core slabs, railway sleepers and bridge girders
- Precast concrete pipes, manholes, box culverts and tunnel segments where a dense, compact face is essential
- Architectural and fair-faced precast panels needing a smooth, blowhole-free surface finish
- High-performance and high-strength ready-mix concrete with low water-cement ratios
- Blended-cement and SCM mixes incorporating fly ash, GGBFS or microsilica for durability
- Self-compacting and flowable concrete where placement around congested reinforcement is required
Key advantages
- High water reduction from a PCE molecule, enabling low w/c ratios and high compressive strength at all ages
- Strong early strength development (16-24 hours) for faster lifting, transfer and bed turnover without raising cement content
- Reduced rate of slump loss compared with naphthalene/melamine superplasticisers, giving longer workable open time
- Low viscosity that flows and self-levels around congested moulds and prestressing strand
- Produces a dense, low-permeability concrete with better resistance to carbonation and chloride attack
- Lower drying shrinkage and creep, reducing the risk of shrinkage cracking
- Compatible with fly ash, GGBFS and microsilica blended systems
- Delivers a clean, fair-faced demoulded finish suited to architectural precast
- Chloride-free formulation, safe for use in prestressed and reinforced concrete
Limitations & considerations
- Optimum dosage must be established by site trial mixes — performance varies with cement source, SCM type, aggregate and ambient temperature
- Overdosing can cause excessive retardation, segregation or bleeding; the 0.3-1.5% range must be respected
- As a high-range PCE water reducer it is engineered for precast/high-performance work, not as a general-purpose plasticiser for low-grade site concrete
- PCE admixtures can be sensitive to clay and silt fines in aggregates, which may reduce efficiency and demand dose adjustment
- Mixing different superplasticiser chemistries (e.g. PCE with naphthalene) in one mix without compatibility testing is not advised
- Liquid product should be protected from freezing and stored within 5-50°C; agitate if any settlement occurs
- Not a substitute for proper curing — early high strength does not remove the need for sound curing practice
Selection & best practice
Always begin with laboratory and site trial mixes using the exact cement, supplementary cementitious materials, aggregates and water that will be used in production, and start near a 0.8% by weight of cement dose before optimising within the 0.3-1.5% window. Add Auracast 270 to the gauging water or at the end of the batching sequence to gain full water-reduction benefit — never onto dry aggregate or cement. Hold the water-cement ratio constant when comparing doses so the strength and workability gains are real, and monitor for any sign of bleeding or segregation at higher doses. In hot weather, account for faster slump loss and adjust timing accordingly. Store drums sealed, out of direct sun, within 5-50°C, and use within the 12-month shelf life. For demanding architectural or structural precast, validate early-strength results against the actual demoulding and transfer schedule rather than relying on 28-day figures alone.
Specifications
| Product type | High-range water-reducing superplasticiser (admixture) |
| Chemical base | Polycarboxylic-ether (PCE) polymer with long lateral side chains |
| Appearance | Light-brown to pale-yellow liquid, instantly dispersible in water |
| Specific gravity | Approx. 1.08 ± 0.02 at 25°C |
| Typical dosage | 0.3-1.5% by weight of cementitious content (≈0.8% typical starting point) |
| Chloride content | Nil / chloride-free (to BS EN 480-10) |
| Standards (India) | IS 9103:1999 superplasticiser; ASTM C494 Type F / Type G (dosage-dependent) |
| Standards (Europe) | Auracast 270 to EN 934-2 high-range water reducer / superplasticiser |
| Pack size | 200 kg drums and bulk supply |
| Shelf life | Minimum 12 months in sealed containers |
| Storage | Store between 5°C and 50°C, protect from frost and direct sunlight |
Industry use cases
Precast manufacturing
Yards producing beams, hollow-core slabs and wall panels dose Auracast 270 to hit lifting strength in 16-24 hours, doubling casting-bed turnover without adding cement.
Infrastructure & transport
Railway sleeper plants, metro and bridge segment casting use it for dense, durable, high-early-strength units that resist chloride and carbonation over a long service life.
Precast concrete pipes & drainage
Pipe, manhole and box-culvert producers get a compact, low-permeability wall and a clean internal/external face suited to spun and vibrated casting.
Architectural precast & facades
Fair-faced panel makers exploit the low-viscosity self-levelling flow to release air and deliver sharp arrises and a smooth, blowhole-free finish straight from the mould.
High-performance ready-mix
RMC plants supplying high-grade structural concrete use it to achieve very low w/c ratios for M50-and-above mixes with workability retention to the pour.
Frequently asked questions
Is Fosroc Auracast 270 the same as Auracast 270M?
What dosage of Auracast 270 should I use?
Which standards does Auracast 270M comply with?
Does Auracast 270 contain chlorides — is it safe for prestressed concrete?
How is Auracast 270 different from a naphthalene superplasticiser like Conplast SP430?
What is the shelf life and how should Auracast 270 be stored?
How we position Fosroc Auracast 270
Auracast 270 / 270M sits at the high-performance end of Fosroc’s admixture portfolio, purpose-built for precast and prestressed work rather than general site concrete. Within the Fosroc range it complements the wider Auracast precast family (Auracast 200, 280) and the Auramix ready-mix superplasticisers, while older naphthalene-based products like Conplast SP430 remain the economical choice for routine plasticising. Specifiers cross-shopping PCE precast superplasticisers will also encounter credible alternatives — Sika’s ViscoCrete range, MBS (Master Builders Solutions) MasterGlenium PCE admixtures, and the admixtures offered by Dr. Fixit (Pidilite) and STP. Auracast 270’s strengths are its long-side-chain PCE chemistry, low viscosity for clean precast finishes and reliable high early strength; the right selection ultimately depends on trial-mix performance with your local cement and SCMs. As an authorised Fosroc distributor and applicator for Delhi NCR and pan-India, Space Arc Engineering supplies genuine Auracast 270M, provides datasheet-backed dosage guidance and supports trial mixing so contractors, consultants and precasters specify with confidence.
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