STP ShaliPlast FS
Chloride-based liquid accelerator from STP — formerly Accelguard 80 — that shortens initial set and speeds demoulding of blocks, pipes and other unreinforced concrete products.
What is it?
A chloride-based liquid accelerating admixture from STP Limited, sold earlier as Accelguard 80, that speeds up the setting and early hardening of concrete, mortar and plaster.
Where is it used?
Unreinforced precast production — blocks, pipes, stepping stones, lintels — plus plain concrete works, cement mortars and plasters, and cold-weather pours where slow setting stalls the cycle.
Why use it?
It cuts initial setting time, builds early strength for quicker mould release, densifies the mix to lower permeability, and does all this at a lower cost than chloride-free accelerators.
How is it applied?
Dispensed into the gauging water at 0.40–1.6 litres per 50 kg bag of cement, with the exact dose fixed by site trials — never sprinkled onto dry cement.
About STP ShaliPlast FS
ShaliPlast FS is STP Limited’s workhorse set accelerator, familiar to older hands under its previous name, Accelguard 80. It is a colourless, freely water-soluble inorganic liquid that goes into the mixing water to pull the initial set of cement forward. For a block yard or pipe plant, that single change compresses the whole production cycle: moulds strip earlier, curing beds turn over faster, and output per shift rises without adding a single extra mould.
Beyond speed, the admixture improves the mix itself. It reduces bleeding and segregation in the plastic state, and the hardened concrete comes out denser, less permeable and stronger in both compression and flexure than an unaccelerated control. Its translucent colour is a quiet bonus for manufacturers of white-cement products — no staining, no grey cast. The trade-off is chemistry: being chloride-based keeps the price down but firmly restricts it to unreinforced work. Space Arc Engineering stocks it in 20 kg and 200 kg drums for Delhi NCR and pan-India dispatch.
The technical insight
Chloride-based accelerators act on the hydration kinetics of cement. Dissolved chloride ions raise the reactivity of tricalcium silicate (C3S), so calcium silicate hydrate — the strength-giving gel — forms earlier and faster, and the heat of hydration arrives sooner. That is exactly what a cold-morning pour or a fast-turnaround mould needs. The same ion, however, is aggressive to embedded steel: chlorides break down the passive oxide film that protects reinforcement and initiate corrosion that no cover thickness can stop. This is why STP’s own datasheet bars the product from RCC, and why every chloride accelerator on the market carries the same restriction. Match the chemistry to the element: plain concrete, yes; steel inside, no.
Where it is used
- Concrete block and paver production where moulds must turn over quickly
- Unreinforced concrete pipes and precast drainage units
- Stepping stones, garden and landscape concrete elements
- Plain (unreinforced) lintels and small cast items
- Cold-weather plain concreting where low temperature delays setting
- PCC works — blinding layers, levelling courses and mass fills on tight programmes
- Cement mortars and plasters that need a faster set
- White-cement products, where the translucent liquid leaves no tint
Key advantages
- Shortens initial setting time, compressing production and pour cycles
- Develops high early strength for fast formwork and mould stripping
- Densifies the concrete and reduces its permeability
- Minimises bleeding and segregation in the fresh mix
- Improves workability along with hardened compressive and flexural strength
- Translucent liquid — safe to use with white cement products
- Freely water-soluble, so it batches easily through the gauging water
- Economical compared with chloride-free accelerating admixtures
Limitations & considerations
- Chloride-based: not advisable for RCC and must never be used with prestressed or post-tensioned steel
- Unsuitable for marine, coastal or other chloride-exposed environments
- Setting response shifts with cement brand, cement content and ambient temperature — site trials are mandatory before production use
- Must enter the mix through the gauging water; direct contact with dry cement is not permitted
- Shelf life is 9 months unopened, and drums need covered storage away from heat
Selection & best practice
Run trial mixes before committing a production line: the effective dose sits anywhere between 0.40 and 1.6 litres per 50 kg bag of cement depending on cement brand and content, target demoulding time and ambient temperature, and only a trial with your actual materials will fix it. Measure the accelerator into the gauging water and charge it with the water — never pour it onto dry cement, where localised flash reactions give erratic setting. In winter, re-trial at the actual morning temperature rather than carrying forward summer dosages. Wash tools and dispensers with water immediately after use. Handle with gloves and eye protection in a ventilated area; if the liquid reaches skin or eyes, rinse with plenty of clean water and seek medical advice for eye contact.
Specifications
| Form | Colourless liquid |
| Chemical nature | Inorganic, chloride-based |
| Specific gravity | 1.30 – 1.35 |
| Solubility | Freely soluble in water |
| Dosage | 0.40 – 1.6 litres per 50 kg bag of cement (fix by site trials) |
| Packing | 20 kg and 200 kg drums |
| Shelf life | 9 months in original unopened packing |
| Storage | Cool, dry, covered storage away from heat |
Industry use cases
Precast & Block Yards
Block, paver and pipe manufacturers dose ShaliPlast FS to strip moulds hours earlier, lifting daily output from the same mould inventory.
Infrastructure & PCC Works
Contractors use it in blinding layers, levelling courses and unreinforced pipe surrounds where an early set keeps excavation and backfilling on programme.
Landscape & Hardscape
Stepping stones, planters and garden elements gain handling strength fast, letting small casting units deliver against short lead times.
Winter Concreting
In North Indian winters, plain concrete that would sit soft all morning sets on schedule, protecting cycle times on cold sites.
White Cement Products
Makers of white and decorative cement items accelerate production without colour staining, thanks to the translucent liquid.
Frequently asked questions
Can I use ShaliPlast FS in reinforced concrete (RCC)?
What is the correct dosage?
How is it added to the mix?
Is this the same product as Accelguard 80?
What pack sizes are available and how long does it keep?
Will it help in cold weather?
How we position STP ShaliPlast FS
ShaliPlast FS is the economical accelerator in our STP range for plain and precast concrete — and deliberately a niche tool. The moment steel enters the element, move to chloride-free chemistry: Fosroc Conplast NC gives comparable acceleration while staying within the chloride limits RCC specifications demand. If permeability is the real concern rather than set time, STP’s ShaliPlast LW+ integral waterproofing admixture addresses it without changing the setting profile, and where reinforcement protection drives the mix design, a corrosion-inhibiting admixture such as STP ShaliPlast CI is the better conversation. Space Arc supplies all of these with dosage guidance — tell us the element and its exposure, and we will match the admixture to it.
Fosroc Conplast NC — Specify Conplast NC whenever the element contains reinforcement — it delivers similar set acceleration without chloride, keeping the mix safe for RCC and within specified chloride limits.
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