About Fosroc Conplast SP360

Fosroc Conplast SP360 is a chloride-free superplasticising admixture from Fosroc’s well-established Conplast concrete-admixture range. Unlike the naphthalene-based superplasticisers such as Conplast SP430, SP360 is built on a blend of specially selected organic polymers and is supplied as a brown solution that disperses instantly in the gauging water. Its defining characteristic is that, alongside strong water reduction, it typically produces a controlled retardation of setting of between one and two hours – so it behaves as a combined high-range water-reducer and set-retarder rather than a pure plasticiser.

That dual action is exactly what Indian concreting conditions often demand. In Delhi NCR and across much of the country, summer placing temperatures, long transit distances from the batching plant to site, and large rafts or slabs poured in a single operation all conspire to flash off slump and force premature stiffening. SP360 disperses the cement particles so the available water works more effectively, allowing a meaningful drop in water content for the same flow; the retarding effect then keeps that flow alive for longer, buying the crew time to place, compact and finish before initial set. The net result is denser, lower-permeability concrete with higher strength at all ages – achieved without raising cement content and without the corrosion risk that chloride-bearing admixtures carry.

Because it is chloride-free, SP360 is safe in prestressed and reinforced concrete and is compatible with other Fosroc admixtures when each is dispensed separately into the mix. As an authorised Fosroc distributor and applicator serving Delhi NCR and pan-India, Space Arc Engineering supplies SP360 with the technical back-up – trial mixes, dosage optimisation and site advice – needed to convert its lab potential into reliable in-place performance. The figures on this page describe the product type and typical Conplast SP-family behaviour; always confirm the exact properties, dosage and standards against the current region-specific Fosroc Technical Data Sheet for your batch.

The technical insight

The chemistry is the key to understanding where SP360 fits. Conventional superplasticisers based on sulphonated naphthalene formaldehyde (SNF), like Conplast SP430, give very high instantaneous water reduction but lose slump relatively quickly. SP360’s organic-polymer blend is formulated so that the dispersing action is paired with a deliberate retardation of the cement hydration kinetics – roughly one to two hours of delayed set under typical conditions. In practice this flattens the slump-loss curve: the concrete does not just start more workable, it stays workable. For a ready-mix producer that translates into a longer open time between batching and discharge, which is decisive when haul times or queueing at site are unpredictable. The trade-off to manage is early strength – a retarder will slow strength gain in the first 24 hours, so striking times for formwork and the timing of finishing operations must be planned around the actual ambient temperature, since retardation lengthens in cold conditions and shortens in heat. Overdosing (for instance, doubling the intended rate) tends to push workability very high and extend retardation further, but properly cured concrete generally recovers its ultimate compressive strength; the real risk of an unintended overdose is excessive set delay and bleeding, not a permanent strength penalty. As with every admixture, the governing rule is that the optimum dose is the one established by trial mixes using the actual cement, supplementary materials (PFA, GGBFS, microsilica) and aggregates that will be used on the job.

Where it is used

• Ready-mix (RMC) concrete requiring extended slump retention from plant to site
• Hot-weather and summer concreting where rapid slump loss is a problem
• Long-haul transit-mixed concrete with extended travel or site-queue times
• Large continuous pours – rafts, mat foundations and thick slabs – to avoid cold joints
• High-strength structural concrete (M30 and above) produced at a reduced water/cement ratio
• Pumped concrete where improved cohesion and flow ease placement
• Reinforced and prestressed concrete (chloride-free, corrosion-safe)
• Durable, low-permeability concrete for water-retaining and aggressive-exposure structures

Key advantages

• Combines high-range water reduction with a controlled 1-2 hour set retardation in a single product
• Extends workability and slump retention – reduces cold joints in long hauls and large pours
• Higher compressive strength at all ages without increasing cement content
• Lower water/cement ratio yields denser, less permeable, more durable concrete
• Chloride-free – safe for prestressed and reinforced concrete and around embedded steel
• Improved cohesion reduces segregation and bleeding and aids pumpability
• Compatible with other Fosroc admixtures when dispensed separately
• Helps offset the slump-killing effect of high ambient temperatures on Indian sites

Limitations & considerations

• Built-in retardation slows early (first-day) strength gain, delaying formwork striking and finishing
• Set-retardation time varies with temperature – longer in cold weather, shorter in heat – so timing must be planned
• Optimum dosage must be established by site trials; it is not a fixed catalogue figure
• Overdosing can cause excessive set delay and bleeding (though ultimate strength generally recovers)
• Not intended as a pure non-retarding superplasticiser – where zero retardation is needed, a different Conplast grade suits better
• Should not be relied upon to fix a poorly proportioned mix; it complements good mix design, not replaces it
• Liquid admixture – protect from extreme temperatures and store in shade to preserve shelf life

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Conplast SP360

Conplast SP360 sits in the middle of the Fosroc Conplast superplasticiser ladder as the option for teams who need both water reduction and extended workability in one product. Within the Fosroc range it pairs naturally with related grades: Conplast SP430 (sulphonated-naphthalene, high early strength) for fast-track and precast work, Conplast SP337 (another organic-polymer high-performance water reducer) for high-grade structural mixes, and the newer high-workability-retention grades such as Conplast SP365/SP366 where very long slump life is the deciding factor; for pure retardation without high-range plasticising, Conplast RP or Conplast R are the simpler retarders. Against the broader Indian market, SP360 competes with naphthalene and polycarboxylate-ether (PCE) retarding superplasticisers from Sika (e.g. the Sika ViscoCrete and Plastiment families), Master Builders Solutions (MasterGlenium and MasterPozzolith ranges), Dr. Fixit/Pidilite admixtures, and STP/Supreme construction-chemical lines – many of which now lead with PCE chemistry for the highest water reduction. SP360’s case rests less on headline water reduction and more on a dependable, well-supported organic-polymer formulation with predictable retardation, backed locally. As an authorised Fosroc distributor and applicator across Delhi NCR and pan-India, Space Arc Engineering can benchmark SP360 against these alternatives on your actual mix, recommend the correct Conplast grade, and stand behind the supply with trial-mix and site support rather than leaving the specification to a generic datasheet.

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