Sika SikaTard R
Chloride-free liquid admixture that holds mortar and concrete workable for longer, preventing cold joints and unplanned set on demanding placements.
What is it?
A ready-to-use, chloride-free liquid admixture based on a hydrocarboxylate blend that controls cement hydration to retard and stabilise sand-cement mortars and concrete mixes.
Where is it used?
Long-duration masonry works, hot-weather ready-mix supply, and concrete placements where extended open time and set control are needed.
Why use it?
It buys placement time without adding chlorides, so crews avoid cold joints, keep workability across long hauls, and reach normal or higher ultimate strengths once curing resumes.
How is it applied?
Added to the gauging water or dosed with it into the mixer at 0.1-0.5% of cement weight for concrete or 0.5-2.0% for mortar, never onto dry cement, and always trial-verified first.
About Sika SikaTard R
SikaTard R is a single-component liquid admixture built around a hydrocarboxylate blend that governs the rate at which cement hydrates. In practice this means it slows down the early stiffening of the mix, giving site teams a controllable window in which mortar or concrete stays soft, cohesive and easy to work. It was developed principally for sand-cement masonry mortars that need to be laid over long periods, but the same retarding and stabilising action makes it useful across a broad range of concrete situations where the natural set clock works against the pour. Because it is chloride-free, with a total chloride ion content below 0.1% by weight, it can be used in reinforced work without introducing a corrosion risk to embedded steel.
For engineers and RMC operators in India, the value is straightforward. Ambient temperatures in Delhi NCR and across much of the country routinely push concrete to stiffen faster than planned, and masonry crews on large facades or repetitive block work lose productivity every time a batch goes off before it can be placed. SikaTard R addresses both problems from the same drum. It is supplied in 200 litre drums and 1000 litre IBCs, carries a hydrocarboxylate chemistry certified to BS EN 934-3 Table 3, and behaves predictably provided the dosage is fixed by trial. Space Arc Engineering supplies it as an authorised Sika distributor with technical backing on mix design and dosage selection.
The technical insight
The retarding effect works by interfering with the early hydration reactions of the cement grains rather than by simply diluting the mix. The hydrocarboxylate molecules adsorb onto the reacting cement surfaces and temporarily hold back the formation of the hydration products that would otherwise cause the paste to stiffen. The result is a longer dormant period during which the mortar or concrete keeps its plasticity and cohesion. What makes SikaTard R practical rather than just a delay agent is how the effect reverses in service. In masonry, once the mortar is placed against absorbent brick or block, moisture is drawn out by suction and evaporation, the retarding films lose their grip, and setting and curing then proceed as normal, often to higher ultimate strengths than an un-retarded control. That self-releasing behaviour is why it is described as stabilising as well as retarding. It also explains the two key cautions: overdosing extends the set so far that joints can be left unset, and saturated masonry units that cannot pull moisture out of the mortar will slow setting further. Correct dosage, established on local materials, is therefore the whole game.
Where it is used
- Retarded, stabilised sand-cement masonry mortars for extended brick and block laying
- Facade and repetitive block work where a single mortar batch must stay workable for hours
- Combination with Sika Intraplast-125 M to produce masonry mortars for absorbent clay, sand-lime and concrete units
- Hot-weather concrete where high ambient temperature accelerates stiffening
- Ready-mixed concrete transported over long haul distances before placement
- Staged concrete placements where cold joints between lifts must be avoided
- Large-pour and slab work needing controlled, uniform set across the section
- General concrete and mortar situations where set retardation or set control is specified
Key advantages
- Chloride-free, with total chloride ion content below 0.1% w/w, so it is safe for reinforced and prestressed elements
- Strong, controllable retardation that lets masonry laying continue over long working periods
- Self-releasing action in masonry, where suction and evaporation allow normal setting and curing to resume
- Can deliver higher ultimate strengths than an equivalent un-retarded mix
- Single liquid dosed straight into the gauging water, with no on-site batching of powders
- Compatible with many other Sika admixtures, allowing tailored mix designs when trialled
- Certified to BS EN 934-3 Table 3 with CE and UKCA marking, giving a documented quality basis
- Twelve-month shelf life and remixable after slow thawing if frost is encountered
Limitations & considerations
- Overdosing can extend setting time excessively and leave mortar unset in finished joints
- Must never be added to dry cement; it goes in with or via the gauging water
- Saturated bricks or blocks reduce the suction that releases the retarder, delaying set and cure
- Actual dosage must be established by trial on local materials, ambient temperature and required workability
- Performance figures are laboratory-based and can vary with site conditions beyond the supplier’s control
- If frozen, it must be thawed slowly at room temperature and remixed thoroughly before use
Selection & best practice
Fix the dosage by laboratory trial before you concrete or lay on site, using your actual sand, cement and expected ambient temperature rather than a generic figure, and re-trial whenever the mix design or component sources change. Start within the recommended bands, 0.1-0.5% of cement weight for concrete and 0.5-2.0% for mortar, and dial in from there against the working life you need. Always dose SikaTard R into the gauging water or add it with the water into the mixer, never onto dry cement, and mix thoroughly for an even distribution. Follow standard good concreting and mortar practice for production and placing, and apply curing as early as possible once the material is down. Where masonry units are highly absorbent, expect faster release of the retarder; where they are saturated, allow for slower setting. For combinations with other Sika products or unusual conditions, confirm the approach with Space Arc’s technical team before committing a full pour.
Specifications
| Product Type | Set-retarding / stabilising liquid admixture |
| Chemical Base | Hydrocarboxylate blend |
| Appearance / Colour | Brown liquid |
| Specific Gravity | 1.18 kg/L |
| Total Chloride Ion Content | <0.1% w/w (chloride-free) |
| Equivalent Sodium Oxide (Alkali) | <4.0% w/w |
| Dosage (Concrete) | Typically 0.1-0.5% by weight of cement |
| Dosage (Mortar) | Typically 0.5-2.0% by weight of cement |
| Standards | Conforms to BS EN 934-3 Table 3 (CE / UKCA marked) |
| Packaging | 200 litre drum, 1000 litre IBC |
| Shelf Life / Storage | 12 months, +5°C to +25°C, protected from sunlight and frost |
Industry use cases
Masonry & Blockwork
Keeps a single mortar batch workable across long laying sessions on large facades and repetitive block work, cutting waste from batches that set before placement.
Ready-Mixed Concrete
Holds slump and cohesion during long-haul deliveries in hot conditions, so concrete arrives placeable rather than part-stiffened.
Large Pours & Slabs
Provides uniform, controlled set across a section during staged placements, helping avoid cold joints between successive lifts.
Hot-Weather Construction
Counteracts the accelerated stiffening that high Indian ambient temperatures cause, restoring a workable placement window on site.
Reinforced & Prestressed Work
Chloride-free chemistry lets teams extend working time near embedded steel without adding a corrosion risk to the element.
Frequently asked questions
Is SikaTard R chloride-free and safe for reinforced concrete?
What dosage of SikaTard R should I use?
How is SikaTard R added to the mix?
Will the retarded mortar or concrete still reach full strength?
What standards does SikaTard R meet?
How is it packaged and stored, and what is the shelf life?
How we position Sika SikaTard R
SikaTard R sits in Space Arc’s admixtures range as the set-control specialist for both mortar and concrete. Within the Sika family it pairs naturally with Sika Intraplast-125 M for producing stable masonry mortars on absorbent units, and can be combined with other Sika admixtures such as the Sika ViscoCrete and Sikament superplasticiser lines where flow retention and water reduction are needed alongside retardation, always confirmed by trial. If your priority is water reduction with retardation in a single hot-weather concrete admixture, our Fosroc Conplast RP264 is a close alternative from another leading brand we distribute. Space Arc supplies all of these across Delhi NCR and Pan-India with technical support on mix design and dosage.
Fosroc Conplast RP264 — Choose the Fosroc option when the pour needs water reduction and retardation together in one hot-weather concrete admixture, rather than SikaTard R’s mortar-and-concrete set-control focus.
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Authorised distribution, technical advice & professional application across Delhi NCR and Pan-India.