Fosroc Cebex SP
Chloride-free expansive superplasticising powder admixture engineered for silo-batched dry mortars and continuous-mix render systems.
What is it?
A chloride-free, powder-form superplasticising admixture that combines high water reduction with controlled expansion and water retention, designed to be pre-blended into dry mortar and cementitious mixes batched through site silos and continuous mixers.
Where is it used?
Silo-batched and ready-to-use dry mortars, machine-applied renders and plasters, masonry and bedding mortars, and factory or site pre-blended cementitious mixes where flow and shrinkage control matter.
Why use it?
It lets you cut mixing water while keeping the mortar highly plastic and cohesive, then compensates for cement shrinkage and retains water during cure, giving denser, crack-resistant mortar with better placing performance.
How is it applied?
Dosed at 0.3 to 0.9 kg per 100 kg of cement and blended dry with the cement during pre-mixing for full homogenisation. It is never added into the mixing water.
About Fosroc Cebex SP
Fosroc Cebex SP is a multi-function powder admixture aimed squarely at modern silo-batched and continuous-mix mortar production. Unlike conventional liquid plasticisers that go into the gauging water, Cebex SP is a dry, free-flowing powder that is pre-blended with the cement, making it ideal for ready-to-use dry mortars supplied to site in silos and discharged through continuous mixers. In a single product it brings together three functions that mortar producers usually have to chase separately: superplasticisation (high water reduction with retained workability), controlled expansion to offset cement shrinkage, and water retention to support proper hydration and reduce plastic-shrinkage cracking. It is chloride-free, which matters wherever the mortar will be in contact with reinforcement, embedded fixings or galvanised mesh. For Indian contractors moving from hand-gauged site mortar to silo-based or pre-bagged systems, Cebex SP is the additive that makes those mixes behave predictably: lower water demand, smoother pumping and rendering, tighter shrinkage and a more durable finished mortar. It sits within Fosroc’s well-known Cebex family of cementitious admixtures alongside grout additives such as Cebex 100, but is specifically formulated for the dry-mortar and render workflow rather than for flowable grouting.
The technical insight
The performance of Cebex SP comes from three mechanisms working in concert within a single powder. The superplasticising fraction disperses cement particles so that the same workability is achieved at a meaningfully lower water/cement ratio; reducing free water is the single most effective lever for raising hardened density, strength and durability of any cementitious mortar. The expansive component generates a controlled, gentle volume increase in the plastic and early-set state, which counteracts the natural drying and chemical shrinkage of the cement so the mortar stays in intimate contact with the substrate and embedded elements rather than pulling away. The water-retaining fraction holds gauging water in the mix, which is critical for thin machine-applied renders on absorbent masonry, where rapid suction would otherwise starve the cement of the water it needs to hydrate and cause dusting, weak skins and surface crazing. Because all three actions are delivered as a dry powder, the additive must be intimately blended with the cement during pre-mixing rather than dosed into the water; this is what guarantees uniform distribution through the whole batch and consistent batch-to-batch behaviour from a silo. The result is a workable, cohesive, effectively shrinkage-compensated mortar from a lower-water mix.
Where it is used
- Silo-batched ready-to-use dry mortars discharged through continuous (auger) mixers
- Machine-applied and hand-applied cement renders and plasters on masonry
- Masonry bedding, jointing and pointing mortars requiring high cohesion
- Pre-blended factory or site dry-mix cementitious products
- Backing coats and float coats where water retention and reduced suction are needed
- General cementitious mixes requiring water reduction with controlled, low-shrinkage behaviour
Key advantages
- Single powder delivers three functions: superplasticising, controlled expansion and water retention
- High water reduction improves hardened density, strength and durability of the mortar
- Controlled expansion offsets cement shrinkage and reduces plastic-shrinkage cracking
- Water retention supports full hydration on absorbent substrates, reducing dusting and crazing
- Chloride-free, so safe for use around reinforcement and embedded metal fixings
- Dry powder form ideal for silo and continuous-mixer production; no liquid dosing equipment needed
- Improves plasticity, cohesion and pumpability for smoother machine application
- Low dosage range (0.3-0.9 kg per 100 kg cement) for economical use
Limitations & considerations
- Must be pre-blended with the cement in the dry premix; must never be added to the mixing water
- Requires thorough homogenisation to perform uniformly, so it suits silo/continuous-mix systems more than crude hand mixing
- Dosage must be calibrated to the specific cement, sand and mix design; over- or under-dosing affects expansion and workability
- It is a mortar/render plasticiser, not a flowable-grout additive (use Cebex 100 / Conbex range for grouts) and not a structural waterproofing product
- Powder admixture should be protected from moisture during storage to avoid clumping and loss of performance
- Trial mixes are strongly advised before full-scale production to confirm water demand and set behaviour with local materials
Selection & best practice
Always add Cebex SP to the dry cement during pre-mixing and blend thoroughly so it is uniformly dispersed through the whole batch; never introduce it into the gauging water, as this prevents proper homogenisation. Start dosing within the 0.3-0.9 kg per 100 kg cement range and fine-tune with trial batches using your actual cement, sand grading and silo/continuous-mixer set-up, checking water demand, workability retention and early shrinkage before committing to production. Keep the powder dry and sealed until use, follow Fosroc’s current TDS and SDS for the destination market, and validate the finished render or mortar on a sample area of the real substrate to confirm suction, adhesion and finish.
Specifications
| Product type | Chloride-free, expansive, superplasticising and water-retaining powder admixture |
| Form | Free-flowing powder |
| Primary function | Water reduction (superplasticising) + controlled expansion + water retention for cementitious mortars |
| Typical dosage | 0.3 to 0.9 kg per 100 kg of cement |
| Chloride content | Chloride-free |
| Method of addition | Pre-blended dry with cement in the premix; never added to mixing water |
| Designed for | Silo-supplied ready-to-use dry mortars and continuous-mixer systems |
| Range | Part of the Fosroc Cebex family of cementitious admixtures |
Industry use cases
Plastering & Rendering Contractors
Machine-applied cement renders on brick and block facades, where water retention curbs substrate suction and the plasticising action keeps the mix pumpable and crack-resistant at a low water/cement ratio.
Dry-Mortar / RMC Producers
Producers of silo-batched ready-to-use mortars use Cebex SP as the in-bag additive that delivers consistent flow, cohesion and shrinkage control batch after batch from continuous mixers.
Masonry & Blockwork
Bedding, jointing and pointing mortars gain higher cohesion and reduced shrinkage, improving bond and reducing hairline cracking in exposed joints.
Repair & Refurbishment
Backing and float coats on old absorbent masonry benefit from retained water and controlled expansion, giving sound, well-bonded coats with less dusting and crazing.
Precast & Pre-blended Products
Factory or site dry-mix cementitious products where uniform powder dosing and reliable water reduction support tighter quality control.
Frequently asked questions
Is Fosroc Cebex SP a liquid or a powder?
What is the correct dosage of Cebex SP?
Can I add Cebex SP to the mixing water?
Does Cebex SP contain chlorides?
How is Cebex SP different from Fosroc Cebex 100?
Does Space Arc supply Cebex SP across India?
How we position Fosroc Cebex SP
Cebex SP occupies a specific niche in the Fosroc admixture portfolio: it is the dry-mortar and render plasticiser, not a grout additive and not a concrete superplasticiser. For flowable cementitious grouts you would step across to Fosroc Cebex 100 (plasticising/expanding grout additive) or the Conbex range, while for structural concrete water reduction the Conplast family (for example Conplast SP430) is the relevant choice; Cebex SP complements rather than competes with these. Where a project needs a curing membrane or mould release alongside the mortar works, Fosroc’s Concure and Reebol ranges are the natural partners. Against the wider Indian market, the closest functional alternatives are dry-mortar and render admixtures from Sika (Sika brand mortar admixtures and plasticisers), MYK Arment / MBS, Dr. Fixit (Pidilite) and STP, several of which offer integral plasticisers and shrinkage-control additives for masonry and render mortars. Cebex SP’s distinguishing pitch is that it bundles superplasticisation, controlled expansion and water retention into one chloride-free powder purpose-built for silo and continuous-mix production, backed by Fosroc’s specification track record. For Indian contractors, consultants and procurement teams standardising on silo-based mortar, that combination of multi-function performance, clean powder dosing and a well-supported brand, supplied locally through Space Arc Engineering with on-site technical backup, is the core reason to specify it.
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