About Fosroc Fosroc® Auramix V200

Fosroc Auramix V200 is a single-component, chloride-free liquid admixture classed as a viscosity modifying agent (VMA). It is not a water reducer or superplasticiser in its own right — instead it is a rheology-modifying companion product, formulated to work in tandem with Fosroc’s polycarboxylate-ether (PCE) superplasticisers from the Auramix and Structuro ranges. Modern high-performance concrete frequently demands two things that pull in opposite directions: very high fluidity with long slump retention, achieved through high PCE dosages, yet stability against segregation and bleeding. When binder content is low, fines are scarce, the gap grading is poor, or aggregate moisture swings batch to batch, those high-fluidity mixes can separate, bleed water to the surface and lose cohesion. Auramix V200 resolves this tension by raising the plastic viscosity of the paste in a controlled, thixotropic manner so that coarse and fine aggregates stay uniformly suspended, while the mix remains fluid, self-levelling and friendly to place.\n\nFor a contractor or ready-mix producer in India, the practical payoff is consistency. The same SCC recipe that works in a controlled lab can fail on site when river sand fines vary or monsoon-wet aggregates change the free water. Auramix V200 buffers the mix against these variations, so the producer can run leaner, more economical mixes without risking honeycombing, bleed channels or pump blockages. Space Arc Engineering supplies and supports Auramix V200 as an authorised Fosroc distributor, advising RMC plants, precast yards and infrastructure contractors on dosage trials and mix design across Delhi NCR and pan-India.

The technical insight

The key technical distinction is that Auramix V200 is a viscosity modifier, not a dispersant. PCE superplasticisers reduce water demand and increase flow by dispersing cement particles; the side effect at high flow is a thin, low-viscosity paste prone to letting aggregates settle. Auramix V200 reintroduces controlled, shear-thinning (thixotropic) viscosity into that paste. At rest, the higher viscosity locks aggregates in place and suppresses bleeding; under the shear of pumping or vibration, the viscosity drops so the concrete still flows and pumps freely with reduced friction and pump pressure. Critically, Fosroc reports that V200 has no effect on setting time (governed by the HRWR/other admixtures), no effect on air entrainment, no effect on initial fluidity or retention, and no adverse effect on early or later-age strength — it acts purely on rheology and stability. Because it is chloride-free (Nil to BS 5075) and near-neutral (pH 7.0-8.0), it is suitable for reinforced and prestressed concrete and is compatible with all Portland cements and supplementary cementitious materials including microsilica, GGBS and fly ash.

Where it is used

• Self-compacting concrete (SCC) for congested reinforcement, columns and architectural elements
• Pumped concrete on high-rise and long-distance placements where reduced pump pressure is needed
• Sprayed (shotcrete) concrete applications requiring cohesive, non-sagging mixes
• Lightweight aggregate concrete prone to aggregate floating or segregation
• SCC and high-flow mixes with low fines content or low binder content
• Mixes with poor or gap-graded aggregate where natural cohesion is lacking
• Stabilising high-PCE-dosage mixes against bleeding and surface laitance

Key advantages

• Eliminates segregation and bleeding in high-fluidity and self-compacting mixes
• Reduces sensitivity to batch-to-batch variation in aggregate moisture and fines
• Lowers pump pressure by reducing plastic viscosity under shear while keeping homogeneity
• Improves passing-ability and pumpability through congested reinforcement
• No effect on setting time, air entrainment or fluidity retention
• No adverse effect on early-age or later-age compressive strength
• Chloride-free (Nil to BS 5075) and pH-neutral — safe for reinforced and prestressed concrete
• Compatible with all Portland cements and with microsilica, GGBS and fly ash
• Effective at low dosages, improving the economics of robust SCC mix design
• Delivers a better, blemish-free surface finish

Limitations & considerations

• Not a water reducer or superplasticiser — it must be used together with a PCE superplasticiser, not as a standalone admixture
• Over-dosage can cause loss of fluidity and a stiffer, harder-to-place mix
• Optimum dosage is mix-specific and must be established by site trials with actual materials
• Performance depends on the partner HRWR/superplasticiser, which still governs set time and water reduction
• Limited 6-month shelf life in unopened containers; requires shaded storage at 5-35°C
• Must be added in the correct sequence (after water and other admixtures) for best results
• Being thixotropic, it requires a calibrated dispenser and good batching control for consistent dosing

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Fosroc® Auramix V200

Auramix V200 sits within Fosroc’s concrete admixtures portfolio as the stability partner to its PCE superplasticisers. It is almost always paired with a Fosroc water-reducing superplasticiser — for example Auramix 200 or the Structuro range — where the superplasticiser delivers flow and water reduction and V200 delivers cohesion and segregation control. Where projects need set retardation or extended slump life, it can be used alongside retarding admixtures such as those in the Conplast range, with V200 still managing rheology. Against competitors, Auramix V200 is the Fosroc equivalent of dedicated VMAs such as Sika’s Sika Stabilizer / SikaViscoCrete-companion VMA grades, MC-Bauchemie’s (MBS) stabilising admixtures, and viscosity modifiers offered through STP and Dr. Fixit/Pidilite’s construction-chemicals lines. The right choice usually comes down to compatibility with the chosen superplasticiser system and local technical support; because V200 is co-engineered with Fosroc’s own PCE chemistry, it is the natural, lowest-risk VMA when the rest of the admixture system is Fosroc. Space Arc Engineering helps specifiers compare these options and run the trials needed to lock in a robust mix design.

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