Fosroc Auramix 350
New-generation polycarboxylic-ether (PCE) based retarding superplasticiser for high water-reduction, long-workability concrete — supplied and applied by Space Arc Engineering, authorised Fosroc distributor across Delhi NCR and Pan-India.
What is it?
A high-performance PCE (polycarboxylic ether) based superplasticising admixture of the retarding type, supplied as a light brown liquid that is instantly dispersible in water.
Where is it used?
Ready-mix concrete (RMC), precast and high-performance concrete, and pumpable mixes where high water reduction and long workability retention are required — especially for Indian infrastructure and hot-weather placements.
Why use it?
It delivers high water reduction and long workability retention from a single admixture, improving strength, durability and pumpability while easing placement over extended transit and handling times.
How is it applied?
Dosed into the concrete at 0.3 to 2.0 percent by weight of total cement or binder content, added to the gauging water or with the final water at the batching plant; site trials confirm the optimum dose for the mix and ambient conditions.
About Fosroc Auramix 350
Fosroc Auramix 350 is a new-generation superplasticising admixture based on polycarboxylic ether (PCE) polymer with a long lateral chain, formulated as a retarding-type water reducer. Per the Fosroc technical data sheet it is supplied as a light brown liquid that is instantly dispersible in water, making it straightforward to dose accurately at a ready-mix or precast batching plant. The long-lateral-chain PCE chemistry provides strong dispersion of cement particles, which is what allows the admixture to deliver high water reduction together with long workability retention — the two properties that matter most for modern Indian concrete production.
In Indian construction practice, Auramix 350 is positioned for ready-mix concrete (RMC), precast, high-performance and pumpable concrete. The combination of high water reduction and a retarding action makes it well suited to longer haul distances, congested-reinforcement pours and hot-weather placements common across Delhi NCR and Pan-India infrastructure projects, where premature slump loss is a recurring challenge. By reducing the water-cement ratio while keeping the mix workable, it supports higher compressive strength, lower permeability and improved long-term durability without compromising placement.
Auramix 350 conforms to IS 9103-1999 (Reaffirmed 2007) and to ASTM C494 Type F & Type G (depending on the dosage used), so specifiers can reference it against the standards that govern Indian and international admixture practice. Space Arc Engineering supplies Auramix 350 as an authorised Fosroc distributor and applicator. Where a project evaluates alternatives, comparable new-generation PCE superplasticisers in the Indian market include Sika ViscoCrete, MasterGlenium from Master Builders Solutions and MC-Bauchemie’s MC-PowerFlow range; we lead with Fosroc and help match the right admixture to your mix design and site conditions.
The technical insight
The defining feature of Auramix 350 is its long-lateral-chain PCE polymer. Unlike older sulphonated-naphthalene (SNF) plasticisers that disperse cement mainly by electrostatic repulsion, PCE polymers also work by steric hindrance — the long side chains physically hold cement grains apart, sustaining dispersion for longer. This is the mechanism behind the admixture’s two headline TDS properties: high water reduction and long workability retention. The retarding action of this grade further extends the open time, which is valuable for RMC transit and large continuous pours in hot weather. Dosage is the key control variable: at 0.3 to 2.0 percent by weight of total cement or binder content, the lower end suits standard water reduction (ASTM C494 Type F behaviour) while higher dosages within the range support water-reducing-and-retarding performance (Type G). Optimum dosage must be established by site trial against the specific cement, supplementary cementitious materials, aggregates and ambient temperature, since over-dosing can extend set times and segregation tendency. The verified physical properties — specific gravity of 1.08 ± 0.02 kg/litre at 25°C, pH of minimum 6.0, and chloride content Nil to IS:456 — confirm it is suitable for reinforced and prestressed concrete where chloride limits apply.
Where it is used
- Ready-mix concrete (RMC) requiring long workability retention over extended transit times
- High-performance concrete demanding high water reduction and improved durability
- Precast and prestressed concrete elements where consistent flow and finish are required
- Pumpable concrete for high-rise and infrastructure placements
- Hot-weather concreting where retardation helps offset rapid slump loss
- Congested-reinforcement and large continuous pours needing extended open time
Key advantages
- New-generation PCE chemistry with long lateral chains for efficient cement dispersion
- High water reduction enabling lower water-cement ratio, higher strength and lower permeability
- Long workability retention that eases placement over extended transit and handling
- Retarding action that supports hot-weather and large-volume pours
- Light brown liquid that is instantly dispersible in water for easy, accurate batching
- Chloride content Nil to IS:456 — suitable for reinforced and prestressed concrete
- Conforms to IS 9103-1999(2007) and ASTM C494 Type F & Type G depending on dosage
Limitations & considerations
- Optimum dosage must be established by site trial; performance varies with cement, SCMs, aggregates and temperature
- Overdosing beyond the recommended range can cause excessive retardation and segregation
- Being retarding-type, it extends setting time — not the first choice where rapid early set is required
- Not interchangeable dose-for-dose with SNF-based plasticisers; PCE mixes need their own trial calibration
- Should be added with the gauging or final water, not to dry cement, for proper dispersion
- Store and handle per the Fosroc TDS; protect from frost and follow shelf-life guidance
Selection & best practice
Add Auramix 350 to the gauging water or with the final portion of mixing water at the batching plant — never onto dry cement — and mix thoroughly to disperse the admixture evenly. Begin trials at a mid-range dose within 0.3 to 2.0 percent by weight of total cement or binder content, then fine-tune against the actual cement, supplementary cementitious materials, aggregates and ambient temperature to confirm the optimum for your target water reduction and workability retention. For hot-weather and long-haul RMC, verify retained slump at the point of discharge rather than only at the plant. Always conduct site trial mixes before full-scale production and refer to the current Fosroc Technical Data Sheet for storage, handling and compatibility guidance.
Specifications
| Chemical base / type | PCE (polycarboxylic ether) super plasticiser, Retarding type |
| Appearance | Light Brown Liquid |
| pH | Minimum 6.0 |
| Volumetric mass @ 25°C (relative density) | 1.08 ± 0.02 kg/litre |
| Chloride content | Nil to IS:456 |
| Dosage | 0.3 to 2.0 percent by weight of total cement or binder content |
| Standards | IS 9103-1999(2007); ASTM C494 Type F & Type G (depending on dosage used) |
| Primary use | High water reduction and long workability retention concrete; pumpable / high-performance / precast concrete |
Industry use cases
Ready-Mix Concrete (RMC)
Maintains workability through long transit and queueing times so concrete arrives and discharges at the required slump, reducing rejected loads and re-tempering on Delhi NCR and Pan-India sites.
Infrastructure & High-Performance Concrete
Enables low water-cement ratio, high-strength, low-permeability mixes for bridges, foundations and structural elements where durability against Indian exposure conditions is critical.
Precast & Prestressed Concrete
Delivers consistent flow and surface finish in factory production while the Nil-chloride formulation suits prestressed elements with strict chloride limits.
Pumpable & High-Rise Concrete
Improves cohesion and pumpability for tall placements and long pump runs, with retained workability that supports continuous pouring schedules.
Hot-Weather Concreting
The retarding action helps offset rapid slump loss and flash setting during peak Indian summer placements, extending the safe working window.
Frequently asked questions
What type of admixture is Fosroc Auramix 350?
What is the recommended dosage of Auramix 350?
Which standards does Auramix 350 conform to?
Is Auramix 350 suitable for reinforced and prestressed concrete?
What is the difference between Auramix 350 and an SNF-based plasticiser?
Does Space Arc Engineering supply Auramix 350 across India?
How we position Fosroc Auramix 350
Lead-with-Fosroc product page for a new-generation PCE retarding superplasticiser, positioned for RMC, precast, high-performance and pumpable concrete in Indian infrastructure and hot-weather contexts; names Sika ViscoCrete, MasterGlenium (Master Builders Solutions) and MC-Bauchemie MC-PowerFlow as credible alternatives while keeping Fosroc primary, with Space Arc Engineering as the authorised distributor/applicator across Delhi NCR and Pan-India.
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