Fosroc Conplast SP500KL
SNF-based high-range water-reducing superplasticiser for flowing, high-strength concrete – chloride-free and compliant with IS:9103, BS:5075 Part 3 and ASTM C494 Type ‘G’.
What is it?
A high-range water-reducing superplasticiser based on Sulphonated Naphthalene Polymers (SNF), supplied as a brown liquid that disperses instantly in water.
Where is it used?
Ready-mix and site-batched structural concrete across Delhi NCR and Pan-India – high-rise, infrastructure, precast and pumped pours where high workability and strength are needed.
Why use it?
Achieves up to 25% water reduction without loss of workability, enabling higher strength, improved durability and easier placement. Chloride-free for use in reinforced and prestressed concrete.
How is it applied?
Added to the gauging water at 0.5%-1.0% by weight of cementitious material (up to 2.5% for microsilica concrete), then mixed thoroughly to disperse before placing.
About Fosroc Conplast SP500KL
Fosroc Conplast SP500KL is a high-range water-reducing superplasticiser based on Sulphonated Naphthalene Polymers (SNF) – a naphthalene-sulphonate chemistry that disperses cement particles to release trapped mixing water. Supplied as a brown to dark-brown liquid that is instantly dispersible in water, it is engineered for Indian construction conditions where high workability, pumpability and strength gain are required without increasing the water content of the mix.
As an authorised Fosroc distributor and applicator serving Delhi NCR and Pan-India, Space Arc Engineering supplies genuine Conplast SP500KL for ready-mix plants, infrastructure contractors and precast yards. The admixture works by dispersing cement grains, which frees water otherwise locked up by particle flocculation. This allows the concrete to be designed in one of two ways: keep the water-cement ratio constant and dramatically increase workability for flowing, self-levelling and pumped concrete, or hold workability constant and cut water by up to 25% to raise compressive strength and improve durability.
Conplast SP500KL is chloride-free (Nil to IS:456), making it suitable for reinforced and prestressed concrete where chloride-induced corrosion of steel must be avoided. It complies with IS:9103:1999, BS:5075 Part 3 and ASTM C494 as a Type ‘G’ (water-reducing and retarding) admixture, giving specifiers a clearly benchmarked product for structural mix designs. In the Fosroc Conplast range it sits alongside alternatives such as Conplast SP430 and SP337; comparable SNF-based superplasticisers in the Indian market include BASF MasterRheobuild, Sika Sikament and Fairmate Fairflo, though Space Arc recommends genuine Fosroc product backed by manufacturer TDS and on-site applicator support.
The technical insight
Conplast SP500KL is an SNF (Sulphonated Naphthalene Polymer) superplasticiser, not a polycarboxylate ether (PCE). The naphthalene-sulphonate molecules adsorb onto cement particles and impart a negative charge, dispersing them by electrostatic repulsion and releasing flocculated water – the mechanism behind its up-to-25% water reduction. As a Type ‘G’ admixture under ASTM C494, it provides combined water-reducing and set-retarding action, useful for maintaining workability during transport and placement in warm Indian conditions. The product entrains approximately 1% additional air, which should be accounted for in yield and durability calculations. With a specific gravity of 1.250-1.270 at 27C, dosing can be measured accurately by volume; the distributor TDS expresses the standard 0.5%-1.0% by-weight dosage as approximately 0.5-1.3 litres per 100 kg of cement. Because it is chloride-free to IS:456, it is compatible with prestressed and heavily reinforced sections without contributing to reinforcement corrosion.
Where it is used
- High-strength structural concrete for high-rise buildings and columns
- Pumped and flowing concrete for tall lifts and congested reinforcement
- Ready-mix concrete requiring retained workability during transit
- Precast and prestressed concrete elements (chloride-free)
- Microsilica / silica-fume concrete at higher dosage for dense, durable mixes
- Water-reduced mixes targeting improved durability and lower permeability
- Infrastructure works – bridges, tunnels, water-retaining structures
Key advantages
- Up to 25% water reduction without loss of workability, raising strength and durability
- SNF chemistry disperses cement effectively for flowing, easily placed concrete
- Chloride-free (Nil to IS:456) – safe for reinforced and prestressed concrete
- Compliant with IS:9103:1999, BS:5075 Part 3 and ASTM C494 Type ‘G’
- Type ‘G’ retarding action helps retain workability during transit in warm climates
- Instantly dispersible in water for straightforward batching
- Improves cohesion and reduces segregation and bleeding in well-designed mixes
- Supplied with genuine Fosroc TDS and applicator support across Delhi NCR and Pan-India
Limitations & considerations
- Performance depends on correct dosage; overdosing can cause excessive retardation or bleeding
- Trial mixes are essential as results vary with cement type, aggregates and ambient temperature
- Not a polycarboxylate (PCE) admixture – slump retention differs from newer PCE superplasticisers
- Approximately 1% additional air is entrained and must be allowed for in mix design
- Should not be the sole measure against chloride or sulphate attack – use with appropriate mix design and protection
- 12-month shelf life requires correct storage conditions to maintain performance
Selection & best practice
Always add Conplast SP500KL to the gauging water rather than to dry cement, and conduct site trial mixes to fix the optimum dosage within 0.5%-1.0% by weight of cementitious material (up to 2.5% only for microsilica concrete) for the specific cement, aggregates and target slump. Account for the approximately 1% entrained air and the Type ‘G’ retarding effect in your mix design, store drums sealed and away from direct heat to protect the 12-month shelf life, and confirm compatibility with any other admixtures before full-scale batching.
Specifications
| Chemical base | Sulphonated Naphthalene Polymers (SNF) |
| Appearance/colour | Brown / dark brown liquid, instantly dispersible in water |
| Specific gravity | 1.250 – 1.270 at 27C |
| Chloride content | Nil (to IS:456) |
| Recommended dosage | 0.5% – 1.0% by weight of cementitious material (standard); up to 2.5% for microsilica concrete (approx. 0.5 – 1.3 litres / 100 kg cement) |
| Air entrainment | Approx. 1% additional air entrained |
| Water reduction | Up to 25% without loss of workability |
| Standards | IS:9103:1999, BS:5075 Part 3, ASTM C494 Type ‘G’ |
| Packaging | 250 kg drum / barrel (also 200 litre containers); bulk |
| Shelf life | 12 months in correct storage |
Industry use cases
High-Rise & Commercial Buildings
Enables high-strength, pumpable concrete that can be placed in tall lifts and congested reinforcement while keeping the water-cement ratio low for durability.
Ready-Mix Concrete (RMC)
Type ‘G’ retarding action helps RMC plants retain workability during transit across Delhi NCR traffic, with chloride-free chemistry suited to all structural mixes.
Precast & Prestressed Yards
Chloride-free formulation protects prestressing steel; up to 25% water reduction gives early strength gain for faster mould turnover.
Infrastructure & Water-Retaining Structures
Lower water-cement ratios produce dense, low-permeability concrete for bridges, tunnels and tanks where durability is critical.
High-Performance / Microsilica Concrete
At higher dosage (up to 2.5%) it disperses cement and silica fume to achieve workable, dense, high-durability mixes.
Frequently asked questions
Is Conplast SP500KL an SNF or PCE superplasticiser?
What is the recommended dosage of Conplast SP500KL?
Does Conplast SP500KL contain chlorides?
Which standards does Conplast SP500KL comply with?
How much water can it reduce?
What is the packaging and shelf life?
Are there alternative brands to Conplast SP500KL?
How we position Fosroc Conplast SP500KL
Mid-range SNF high-range water-reducing superplasticiser within the Fosroc Conplast family, positioned for high-strength, pumpable and chloride-free structural concrete; supplied by Space Arc Engineering as an authorised Fosroc distributor across Delhi NCR and Pan-India.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.