Fosroc Auracast 295
A new-generation, high-activity water-reducing superplasticiser engineered for very high-strength precast, prestressed and ready-mixed concrete where low water/cement ratios and fast early-strength gain matter.
What is it?
A high-range water-reducing superplasticising admixture from Fosroc’s Auracast range, built on new-generation polymer chemistry to disperse cement at very low water/cement ratios.
Where is it used?
Precast yards, prestressed and tunnel-segment plants, and ready-mix batching units producing high-strength, high-finish structural concrete.
Why use it?
It sharply cuts mixing water at a given workability, lifting early and ultimate strengths and accelerating formwork/mould stripping cycles without sacrificing surface finish.
How is it applied?
Dosed into the mix water or added with the final water charge at the batcher, typically 0.5-2.0% by weight of cement (0.8% as a starting point), then trial-optimised on site.
About Fosroc Auracast 295
Fosroc Auracast 295 is a high-performance, high-activity water-reducing superplasticiser positioned at the demanding end of Fosroc’s Auracast admixture family. It is designed for concrete producers who need to push compressive strength up while pulling the water/cement (w/c) ratio down — the two levers that govern durability, density and early de-moulding speed in modern structural concrete. Unlike older lignosulphonate or naphthalene-based plasticisers, Auracast 295 relies on a new-generation polymer dispersant that holds cement particles apart far more efficiently, so a given slump or flow can be achieved with substantially less water. The practical outcome is a denser, lower-permeability matrix that gains strength quickly at early ages and continues to develop it over the long term. For precast and prestressed operations in particular, that early-strength behaviour translates directly into faster mould turnaround and shorter steam-curing cycles, which is where the product earns its keep on a cost-per-cubic-metre basis. The admixture is water-based, non-flammable, and complies with UNE-EN 934-2:2010 Tables 3.1 and 3.2 as a high-activity water reducer / superplasticiser, with a water-soluble chloride content of 0.10% or less, making it suitable for use in reinforced and prestressed concrete. In the Indian market it is supplied by Fosroc Chemicals (India) and is specified for ready-mixed concrete, high-finish precast, prestressed elements and segmental tunnel-lining work. Space Arc Engineering supplies and supports Auracast 295 across Delhi NCR and Pan-India as an authorised Fosroc distributor, with technical guidance on trial mixes and dosage optimisation.
The technical insight
The performance of Auracast 295 comes from steric (physical) dispersion rather than the weaker electrostatic repulsion of conventional plasticisers. The polymer adsorbs onto cement grains and keeps them physically separated, freeing up water that would otherwise be trapped in flocculated cement clusters. This is why high water reduction is achievable without bleeding or segregation. Two consequences matter on site. First, because more of the gauging water is doing useful work, the same workability is reached at a markedly lower w/c ratio — and since strength and permeability are governed by w/c, you get both higher strength and better durability from the same cement content. Second, the admixture exhibits a hardening-accelerating effect that is especially valuable for early formwork stripping and steam-cured precast, where producers need elements to reach handling/transfer strength within hours, not days. Dosage is the key control variable: the recommended starting point is around 0.8% by weight of cement, with a working window of 0.5% to 2.0%, and a tighter 0.6-1.0% band cited for precast tunnel segments. Because polymer admixtures are sensitive to cement chemistry, fines and ambient temperature, the correct dosage for a given mix must be established by trial — overdosing can cause retardation or excessive retained workability, while underdosing leaves strength on the table.
Where it is used
- Ready-mixed concrete (RMC) requiring high workability at low water/cement ratio
- High-strength precast concrete where an excellent surface finish is essential
- Prestressed concrete elements needing high transfer and ultimate strengths
- Precast segmental concrete (tunnel linings, viaduct segments) demanding high early strength
- Steam-cured precast units where accelerated early-strength gain shortens curing cycles
- Low w/c, high-durability structural concrete for aggressive or marine exposure
Key advantages
- High range of water reduction at a given workability, improving both early and ultimate compressive strength
- Hardening-accelerating effect enables faster mould stripping and shorter steam-curing cycles in precast
- Produces compact, low-permeability concrete with a clean, defect-free surface finish
- Low water-soluble chloride content (≤ 0.10%), safe for reinforced and prestressed concrete
- Compliant with EN 934-2:2010 (Tables 3.1 & 3.2) as a high-activity water reducer / superplasticiser
- Water-based and non-flammable, simplifying storage and on-site handling
Limitations & considerations
- Optimum dosage is mix-specific and must be confirmed by site trials; overdosing can cause excessive retardation or retained workability
- Performance varies with cement type, fines content and ambient temperature, so consistent QC is needed
- As a high-activity superplasticiser it is a specialist product — for routine workability on standard grades a mid-range plasticiser may be more economical
- Should be stored within 2°C-40°C and used within its 6-month shelf life; protect from freezing
- Does not replace good mix design, curing or compaction — it complements, not substitutes for, sound site practice
- Country-specific datasheet values (e.g. exact specific gravity/colour) should be confirmed against the current Fosroc India TDS before specification
Selection & best practice
Always establish dosage by laboratory and site trial against the actual cement, aggregates and target grade rather than defaulting to a single figure — begin near 0.8% by weight of cement (0.6-1.0% for tunnel segments) and adjust within the 0.5-2.0% window to hit the required slump/flow and transfer strength. Add Auracast 295 to the mixing water or with the final portion of the gauging water, never to dry cement, and maintain adequate mixing time for full dispersion. Verify the reduced w/c ratio is being held in production, since the strength and durability gains depend on it. Store containers sealed between 2°C and 40°C, protect from freezing, and use within six months. For prestressed and steam-cured work, confirm early-age strength by cube/cylinder testing before transfer or de-moulding. When in doubt on compatibility with other admixtures or supplementary cementitious materials, run a combined trial — and consult Space Arc Engineering’s technical team for mix-design support.
Specifications
| Product type | High-activity water-reducing admixture / superplasticiser (new-generation polymer) |
| Primary function | High-range water reduction + early-strength acceleration |
| Base | Water-based, non-flammable liquid |
| Recommended dosage | 0.5% to 2.0% by weight of cement (0.8% typical starting point) |
| Dosage for precast tunnel segments | 0.6% to 1.0% by weight of cement |
| Water-soluble chloride content (Cl⁻) | ≤ 0.10% |
| Standard compliance | UNE-EN 934-2:2010, Tables 3.1 & 3.2 (high-activity water reducer / superplasticiser) |
| Shelf life | 6 months in dry, unopened original containers |
| Storage temperature | 2°C to 40°C (protect from freezing) |
| Supply (India) | Fosroc Chemicals (India); supplied via Space Arc Engineering, Delhi NCR & Pan-India |
Industry use cases
Precast & Prefab Manufacturing
Precast yards use Auracast 295 to reach high transfer strength quickly, freeing moulds faster and increasing daily casting throughput while keeping a sharp, blemish-free surface finish on architectural and structural units.
Infrastructure & Tunnelling
In segmental tunnel-lining and viaduct-segment production, the 0.6-1.0% dosage band delivers the high early strength needed for rapid de-moulding and stacking, supporting tight precast production cycles on metro and highway projects.
Ready-Mixed Concrete
RMC plants supplying high-grade structural concrete (M50 and above) exploit the water reduction to hold workability for placement while achieving low w/c, high-density, durable concrete for high-rise and bridge works.
Prestressed Concrete
Prestressing beds for girders, sleepers and hollow-core slabs rely on the early- and ultimate-strength gain to permit early strand transfer and to meet demanding long-term design strengths.
Durability-Critical & Marine Structures
Where chloride and sulphate exposure threaten service life, the low w/c, low-permeability matrix achievable with Auracast 295 — combined with its low chloride content — supports more durable reinforced concrete.
Frequently asked questions
What exactly is Fosroc Auracast 295 and what does it do?
What is the recommended dosage of Auracast 295?
Is Auracast 295 safe for reinforced and prestressed concrete?
How is it different from a standard plasticiser like Conplast?
How should Auracast 295 be stored and what is its shelf life?
Can I get Auracast 295 in Delhi NCR and across India?
How we position Fosroc Auracast 295
Auracast 295 sits at the high-performance end of Fosroc’s superplasticiser portfolio, above general-purpose options in the Conplast range and alongside the other high-activity Auracast grades (such as Auracast 200, 280 and 270M) — the right choice when low w/c, very high strength and fast precast turnaround are the priorities rather than routine workability. It pairs naturally with complementary Fosroc products like Conplast curing compounds and Reebol mould-release agents in a precast workflow. Against the broader market, credible equivalents Indian specifiers will recognise include Sika’s ViscoCrete polycarboxylate-ether superplasticisers, the MBS (Master Builders Solutions) MasterGlenium PCE range, BASF-lineage PCE admixtures, and STP/Dr. Fixit admixtures for more general concrete work. Dr. Fixit and many STP lines are stronger in waterproofing and repair than in high-end precast superplasticising, so for very high-strength, high-finish precast and prestressed concrete the realistic head-to-head is typically Auracast 295 versus Sika ViscoCrete or MasterGlenium. Selection should ultimately come down to local technical support, verified trial performance with your cement, and supply reliability — areas where Space Arc Engineering provides hands-on backing for the Fosroc system in Delhi NCR and Pan-India.
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