About Fosroc Conplast SP440

Fosroc Conplast SP440 is a liquid concrete admixture in the Conplast superplasticiser family, supplied as a brown, water-dispersible liquid based on a blend of organic polymers (a sulphonated-naphthalene type chemistry typical of this product class). It is engineered for two outcomes that matter most on Indian sites: a large reduction in mixing water and a noticeably longer working life for the fresh concrete. Where the better-known Conplast SP430 is geared toward high early strength, SP440 is positioned as the slump-retaining member of the range, making it the natural choice when concrete must survive long haulage, queuing at the pump, or extended placing in summer heat without slump collapse. SP440 is chloride-free, so it is safe in prestressed and post-tensioned work, with sulphate-resisting cements and where marine or reactive aggregates are in play. It works with all common cements — OPC, PPC, PSC and SRC — the only general exclusion being high-alumina cement. For Space Arc Engineering’s clients across Delhi NCR and pan-India, SP440 sits between conventional plasticisers and premium PCE hyperplasticisers: it delivers genuine high-range performance and retention at a competitive naphthalene-based price point, which is why it is widely specified for general ready-mix and structural concrete rather than only the most specialised pours. As an authorised Fosroc distributor and applicator, we supply SP440 with batching-plant trial support so the dosage is dialled in to your actual cement, fly-ash content and site temperature before the first structural pour.

The technical insight

SP440’s value comes from how it disperses cement. Naphthalene-based superplasticisers adsorb onto cement grains and impart a strong negative charge, so particles repel each other electrostatically and release the water otherwise trapped in flocs. That freed water becomes workability you can spend two ways: keep the water-cement ratio and gain flow, or hold the workability and strip out water for a denser, stronger, lower-permeability matrix. SP440’s formulation is tuned so this dispersion persists longer than a standard high-early-strength superplasticiser, which is what produces its slump-retention behaviour and its ASTM C494 Type ‘D’ (water-reducing and retarding) and Type ‘G’ (high-range water-reducing and retarding) classification. The retarding action delays initial set, buying time in transit and placing — useful in summer but something to plan around in cold weather or where fast formwork turnaround is needed. Because dispersion is electrostatic, performance is sensitive to the cement and fly-ash you actually use, so a plant trial matters more than a catalogue figure. The roughly 1% additional entrained air is incidental, not an air-entrainment function: SP440 is not a substitute for a dedicated air-entrainer in freeze-thaw exposure.

Where it is used

• Ready-mix concrete requiring retained workability through long transit and discharge times
• Pumped concrete and long-distance pours where slump must be held at the point of placing
• High-grade structural concrete (M30 and above) for rafts, columns, shear walls and transfer slabs
• Hot-weather concreting where standard mixes lose slump before placing and compaction
• Prestressed and post-tensioned elements (chloride-free, safe around tendons)
• Concrete with sulphate-resisting cement, marine aggregates or in aggressive ground
• Flowing / free-flowing concrete in congested-reinforcement sections needing minimal compaction
• Dense, low-permeability concrete for water-retaining and durability-critical structures

Key advantages

• Up to 25% water reduction for higher strength and reduced permeability at the same workability
• Extended slump retention — concrete stays placeable through long haul and pump queues
• Chloride-free: safe in prestressed, post-tensioned and sulphate-resisting concrete
• Improves cohesion and surface finish by dispersing cement and minimising segregation
• Compatible with all common cements (OPC/PPC/PSC/SRC) except high-alumina cement
• Can be used with other Fosroc admixtures when each is batched separately
• Enables flowing concrete that needs little or no compaction in congested sections
• Competitively priced naphthalene chemistry versus premium PCE hyperplasticisers

Limitations & considerations

• Retarding action delays set — not ideal for cold weather or fast formwork-cycle work without adjustment
• Overdosing can cause excessive retardation, bleeding or segregation; trials are essential
• Naphthalene chemistry gives less slump life and lower water reduction than top-tier PCE hyperplasticisers
• Not a dedicated air-entrainer — does not replace one for freeze-thaw durability
• Not for use with high-alumina cement
• Performance varies with cement source and fly-ash content, so plant trials are required
• Must be added to the water, never directly onto dry cement
• Liquid admixture needs protection from extreme temperatures and frost in storage

Selection & best practice

Specifications

Industry use cases

How we position Fosroc Conplast SP440

Within the Fosroc range, Conplast SP440 is the slump-retaining, retarding superplasticiser that complements the high-early-strength Conplast SP430 and SP430 G8, and sits below Fosroc’s premium PCE hyperplasticisers (the Auracast / Structuro families) used for self-compacting and very high-grade concrete. For everyday plasticising where retention is not the priority, the lighter Conplast range (e.g. plasticisers and Conplast SP420-class products) is the economical step down. Against competitors, SP440 maps to naphthalene-based retarding superplasticisers such as Sika Plastiment / older Sikament grades, BASF/Master Builders Solutions Pozzolith and RHEOBUILD-type products, and similar offerings from Dr. Fixit (Pidilite) and STP. PCE-based products from these brands (Sika ViscoCrete, MasterGlenium) outperform SP440 on slump life and maximum water reduction but at a higher price — SP440’s advantage is dependable high-range performance and retention at a competitive naphthalene price point, backed by Fosroc’s widely specified, IS 9103 / ASTM C494-compliant system. Space Arc Engineering, as an authorised Fosroc distributor and applicator for Delhi NCR and pan-India, supplies SP440 with batching-plant trial support and can advise where SP430, SP440 or a PCE hyperplasticiser is the right fit for your grade, haul distance and pour conditions.

Related Concrete Admixtures products

View all Concrete Admixtures products →