Fosroc Conplast NC
Chloride-free accelerating and water-reducing admixture based on inorganic formate, for faster setting and early strength gain in reinforced concrete and mortar.
What is it?
Fosroc Conplast NC is a chloride-free accelerating admixture whose main active ingredient is an inorganic formate. It speeds up the setting and early strength development of concrete and mortar while also acting as a plasticiser/water-reducer, all without introducing chlorides that could corrode steel reinforcement.
Where is it used?
Precast concrete, cold-weather and low-temperature concreting, fast-track repairs, and bricklaying or rendering mortar across RMC plants, precast yards and infrastructure sites in Delhi NCR and Pan-India.
Why use it?
It delivers the early-strength and rapid-set benefits contractors traditionally got from calcium chloride, but with a ‘Nil’ chloride content to BS 5075, so it is safe for reinforced and prestressed concrete where chloride-induced corrosion is a concern.
How is it applied?
Added to the concrete or mortar mix at 2.0 to 3.0 litres per 100 kg of cement, dispensed with the gauging water; it suits all types of Portland cement but must not be used with high alumina cement.
About Fosroc Conplast NC
Fosroc Conplast NC is a non-chloride accelerating admixture engineered to give concrete and mortar a faster set and higher early strength without the corrosion risk associated with calcium-chloride accelerators. Per Fosroc’s own Technical Data Sheet, the main active ingredient is an inorganic formate; it is therefore an inorganic-formate-based accelerator, not a polycarboxylate ether (PCE) and not a sulphonated-naphthalene (SNF) superplasticiser. In addition to accelerating hydration, Conplast NC has a useful plasticising/water-reducing action, helping improve workability or allowing a modest water reduction at a given slump.
The product is a light straw coloured liquid that is simply added with the gauging water at the mixer or batching plant. Because its chloride content is ‘Nil’ to BS 5075, Conplast NC is suitable for reinforced and prestressed concrete, precast units and steel-containing mortars where Indian site teams would otherwise be barred from using chloride-based accelerators. It is compatible with all types of Portland cement but is not suitable for high alumina cement.
For Indian construction conditions, this makes Conplast NC particularly valuable in precast yards needing faster mould turnaround, in winter and high-altitude concreting in the north where low temperatures slow hydration, and in fast-track repair and bricklaying work where early strength keeps the programme moving. Space Arc Engineering supplies Fosroc Conplast NC as an authorised Fosroc distributor and applicator, with technical support across Delhi NCR and Pan-India. Where a project specification calls for a non-chloride accelerator, comparable products from manufacturers such as Sika, BASF Master Builders Solutions and MC-Bauchemie may also be encountered, but Conplast NC remains the natural Fosroc-system choice for accelerated set and early strength.
The technical insight
The defining characteristic of Conplast NC is its inorganic-formate chemistry. Formate-based accelerators promote faster cement hydration and early strength gain without the chloride ion that drives reinforcement corrosion, which is why Conplast NC can be classified as ASTM C494 Type C (accelerating admixture) and complies with BS 5075 Part 1 while keeping chloride content ‘Nil’ to BS 5075. Its specific gravity is 1.260 to 1.270 at 27 degrees C, it entrains less than 1% air so it does not significantly alter the concrete’s air content or strength on that account, and it has a freezing point of -16 degrees C, which is relevant to storage and to cold-weather use. It should not be confused with a high-range water reducer: while it does plasticise and reduce water, it is fundamentally an accelerator, and it must be dosed and trialled accordingly rather than treated as a PCE or SNF superplasticiser.
Where it is used
- Precast concrete production requiring faster mould turnaround and early demoulding strength
- Cold-weather and low-temperature concreting where hydration is otherwise slow
- Fast-track concrete repairs needing rapid early strength gain
- Bricklaying and rendering mortar requiring accelerated set
- Reinforced and prestressed concrete where chloride-based accelerators are prohibited
Key advantages
- Chloride-free (Nil to BS 5075), so safe for reinforced and prestressed concrete
- Accelerates setting and early strength gain to support fast-track and precast programmes
- Dual action: also plasticises and reduces water for improved workability
- Compatible with all types of Portland cement
- Low air entrainment (less than 1%), so minimal impact on hardened concrete properties
- Complies with ASTM C494 Type C and BS 5075 Part 1
Limitations & considerations
- Not suitable for use with high alumina cement
- An accelerating admixture, not a high-range superplasticiser; should not be relied on for large water reductions
- Dosage must stay within the recommended 2.0 to 3.0 litres per 100 kg cement and be confirmed by site trials
- Acceleration effect is temperature-dependent and should be verified under actual ambient conditions
- Has a freezing point of -16 degrees C; protect from freezing in extreme cold storage
Selection & best practice
Add Conplast NC with the gauging water rather than to dry cement or aggregates, and never dose it onto dry cement. Use within the recommended range of 2.0 to 3.0 litres per 100 kg of cement, confirming the exact dosage and resulting set/strength behaviour by trial mixes using the actual job materials and at the expected ambient temperature, since the acceleration effect is temperature-sensitive. Verify the cement type is a Portland cement and never use the product with high alumina cement. Follow good concreting and curing practice, and consult Space Arc Engineering for project-specific guidance.
Specifications
| Chemical base / active ingredient | Inorganic formate (chloride-free accelerator); also acts as a plasticiser/water-reducer |
| Appearance | Light straw coloured liquid |
| Specific gravity | 1.260 – 1.270 at 27 deg C |
| Chloride content | Nil to BS 5075 |
| Air entrainment | Less than 1% |
| Freezing point | -16 deg C |
| Dosage | 2.0 to 3.0 litres per 100 kg cement |
| Standard compliance | BS 5075 Part 1 and ASTM C494 Type C |
| Cement compatibility | All types of Portland cement; NOT suitable for high alumina cement |
| Primary use | Accelerate setting and early strength gain without chloride; precast, cold-weather concreting, repairs, bricklaying mortar |
Industry use cases
Precast Concrete
Speeds early strength gain so precast yards can demould and turn over moulds faster, improving daily output without chloride risk to embedded steel.
Cold-Weather Concreting
Counteracts slow hydration in winter and high-altitude pours across northern India, helping concrete set and gain strength at low ambient temperatures.
Repairs and Refurbishment
Accelerates early strength in patch and structural repairs so trafficking or load can resume sooner on fast-track jobs.
Masonry and Plaster
Used in bricklaying and rendering mortar to accelerate set, keeping masonry programmes on schedule.
Reinforced and Prestressed Concrete
Provides accelerator benefits where chloride-based products are banned, protecting reinforcement and tendons from chloride-induced corrosion.
Frequently asked questions
Is Fosroc Conplast NC chloride-free?
What is the active chemistry of Conplast NC?
What is the recommended dosage?
Which standards does Conplast NC comply with?
Can it be used with all cements?
Is Conplast NC a superplasticiser?
How we position Fosroc Conplast NC
Within the Fosroc admixture range, Conplast NC is the chloride-free accelerator: choose it when you need faster setting and early strength in reinforced or prestressed concrete, precast, cold-weather pours, repairs or mortar without introducing chlorides. It sits apart from Fosroc’s PCE/SNF-based superplasticisers and high-range water reducers, which are selected primarily for workability and water reduction; where corrosion-safe acceleration is the goal, Conplast NC is the natural choice, with comparable non-chloride accelerators from Sika, BASF Master Builders Solutions and MC-Bauchemie as alternative brands sometimes specified.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.