Concrete admixtures for workability, set control and durability
Plasticisers, superplasticisers, retarders, accelerators and integral waterproofers — the chemistry that decides whether concrete places properly, gains strength on programme and lasts. Specified by dose, not by drum.
Pick a family — see the window it works in
An admixture is not a thing you install — it is a dose. Select a family to see its working range, what goes wrong on either side of it, and the products we stock.
Plasticiser (water-reducing admixture)
The cheapest way to buy workability. Reduces water demand around 5–12% at a low dose, without changing how the mix is batched.
- General structural grades where cost governs
- Short haul, moderate ambient temperature
- Where slump retention is not critical
Superplasticiser — SNF
Sulphonated naphthalene. Strong early flow at competitive cost, and the most-used high-range water reducer in Indian ready-mix and precast.
- General structural grades, RMC and precast
- Cost-governed work where long slump retention is not needed
- Short to moderate haul distances
Superplasticiser — PCE
Polycarboxylate ether. Over 25% water reduction at a lower dose, with slump retention engineered in rather than bought back with a retarder.
- High-grade and high-performance concrete
- Long hauls needing genuine slump retention
- Self-compacting and congested-reinforcement pours
Retarder
Buys placing time in heat. Delays initial set so a large or hot-weather pour can be placed and finished as one monolithic unit.
- Hot-weather concreting and long hauls
- Large continuous pours and rafts
- Where a cold joint would be structurally unacceptable
Accelerator
Brings early strength forward in cold weather, or where the formwork cycle governs the programme rather than the concrete does.
- Cold-weather concreting
- Fast formwork cycles and precast turnaround
- Repair work that must take early load
Integral waterproofer
Cuts permeability from within the concrete itself — the first line of defence for water-retaining and below-grade structures.
- Water tanks, rafts and retaining walls
- Basements and below-grade structures
- Alongside a membrane — never instead of one
Ranges are typical working windows. Always confirm against the product data sheet and a trial mix with your actual cement and aggregate.
Six families, six different jobs
Admixtures are not interchangeable. Each family changes one property of the mix — and changes others as a side effect. These are the three we are asked to specify most often.
SNF (sulphonated naphthalene formaldehyde) superplasticisers
Older-generation high-range water reducers giving strong early flow at competitive cost. Page-named: Sikament, Fosroc Conplast SP series.
Set retarders
Extend the working time of the fresh mix by delaying hydration. Page-named: Plastiment / Conplast retarders; catalogue includes SikaTard R, Centrament Retard, MC-Retard 060.
Integral (mass) waterproofing admixtures
Reduce concrete permeability throughout the section rather than at the surface. Page-named: Fosroc Conplast integral waterproofing range, Dr. Fixit / STP equivalents.
Six dosage failures we are called in to diagnose
Rapid slump loss and early stiffening on site
Usual cause: High ambient temperature during Indian summers, compounded by long transit or haul times
Fix: Retarders and slump-retaining PCEs — MasterPolyheed, a long-life Fosroc Auramix, or a PCE plus a Plastiment/Conplast retarder — with dosage set for the actual ambient temperature and haul distance
Pump blockages and honeycombing in densely reinforced sections
Usual cause: Insufficient flow and poor filling ability of the mix through congested reinforcement
Fix: High-flow superplasticisers and self-compacting concrete (SCC) mixes
Slow demoulding holding up precast cycles
Usual cause: Insufficient early-age strength gain to allow safe lifting and bed turnover
Fix: High-early-strength accelerating PCEs — Sika ViscoCrete 20 HE, MasterGlenium ACE or Fosroc Auracast
Water ingress and dampness in basements and tanks
Usual cause: Permeable concrete section — surface treatment alone does not address permeability through the body of the concrete
Fix: Integral (mass) waterproofing admixtures plus a low-permeability, low w/c mix; page pairs these with matching surface waterproofing systems for a complete solution
Cold-weather strength delays
Usual cause: Low ambient temperature slowing cement hydration
Fix: Accelerators to speed early strength gain
Segregation and bleeding in flowing concrete
Usual cause: Highly fluid mixes lack the paste viscosity to hold coarse aggregate in suspension
Fix: Viscosity-modifying agents (VMA), typically dosed alongside the PCE
One Fosroc admixture per job
As an authorised Fosroc distributor we lead with Conplast and Auramix because between them they cover every family on this page with documented dosage ranges — and we say so plainly where another brand suits the mix better.
Conplast R
Retarder for hot-weather placing where you need working time without losing set.
Liquid admixture is a dated product — ours is traceable
Space Arc Engineering is an Authorised Distributor and Applicator in India for Fosroc, Sika, Dr. Fixit, MC-Bauchemie, STP, UltraTech, Master Builders Solutions and Asian Paints SmartCare. Admixtures are liquids with a shelf life: they stratify, freeze and lose activity with age, and a drum of unknown provenance will not deliver its stated water reduction. Every IBC, drum and carboy moves through our own warehousing with batch and date records intact — so the dose on your mix design is the dose you actually get.
All Concrete Admixtures products we supply
579 genuine concrete admixtures products from our authorised brands — supplied & applied across Delhi NCR and pan-India.
Fosroc · 299 Preferred
MC-Bauchemie · 112
Sika · 84
Dr. Fixit · 9
STP · 38
Other · 34
Why specify admixtures through us
We start from the mix, not the drum
Cement type, w/c ratio, ambient temperature and haul time decide the family and the dose. We ask for those first, then name the product — which is why we sometimes recommend a cheaper plasticiser than the one you asked for.
Batch-traceable, in-date stock
Liquid admixtures lose activity as they age. Every container arrives with batch and date records intact, so the water reduction on the data sheet is the water reduction on your pour.
Trial mixes, not guesswork
We support trial mixes and site dosage checks so the working window is confirmed against your actual cement and aggregate — before it goes into a structural pour.
Frequently asked questions
Which concrete admixture is best for high-strength, durable concrete?
For high-strength, low water-cement ratio concrete, a PCE (polycarboxylate ether) hyperplasticiser is the best choice — it gives maximum water reduction with long workability retention. Strong options include Sika ViscoCrete, Fosroc Auramix 500-series and Master Builders MasterGlenium. The exact product and dosage should be fixed by a trial mix with your cement and SCMs. Space Arc can supply all three brands and help you select and trial the right one — call +91 9999155255.
What is the difference between a PCE and an SNF superplasticiser?
PCE (polycarboxylate ether) admixtures, like Sika ViscoCrete and MasterGlenium, offer higher water reduction and much longer slump retention, making them ideal for high-grade, self-compacting and durable concrete. SNF (sulphonated naphthalene formaldehyde) admixtures, like Sikament and Conplast SP, give good early flow at a lower cost and suit general structural grades. PCE usually wins on overall economy once cement savings are counted.
Which admixture should I use for hot-weather concreting in India?
In hot weather the main risks are rapid slump loss and early stiffening, so use a retarding or slump-retaining superplasticiser such as Master Builders MasterPolyheed, a long-life Fosroc Auramix, or a PCE combined with a Plastiment/Conplast retarder. Pair this with good curing using a curing compound. Space Arc’s technical team can recommend the right dosage for your ambient temperature and haul distance.
What admixture is used for waterproof or water-retaining concrete?
Use an integral (mass) waterproofing admixture that reduces concrete permeability throughout the section — such as the Fosroc Conplast integral waterproofing range or Dr. Fixit/STP equivalents — combined with a low water-cement ratio mix and a superplasticiser. This is standard for basements, water tanks, STPs and retaining structures. Space Arc supplies the admixtures and matching surface waterproofing systems for a complete solution.
What is a shotcrete accelerator and which products are available?
A shotcrete (sprayed concrete) accelerator flash-sets concrete the moment it hits the surface, allowing thick build-up on tunnel crowns, slopes and rock faces. Leading products are Sika Sigunit and Master Builders MasterRoc, used with a sprayable-grade superplasticiser. Space Arc supplies these for tunnelling, mining and slope-stabilisation projects across India.
Where can I buy Sika, Fosroc and Master Builders admixtures in India, and what is the price?
Space Arc Engineering is an authorized project distributor and applicator supplying Sika, Fosroc and Master Builders Solutions admixtures across India. Pricing depends on product, pack size and project quantity. For a project quote and current rates, contact Space Arc at +91 9999155255 or [email protected].
Can admixtures from different brands be mixed in the same concrete?
As a rule, do not combine admixtures from different brands or even incompatible products within a brand without verification — they can interact and cause loss of workability, retardation or air entrainment. Always run a trial mix to confirm compatibility with your cement and SCMs. Space Arc can advise on compatible combinations and supply a single coordinated package to avoid these risks.
Do I need both a superplasticiser and a curing compound?
They do different jobs. A superplasticiser controls workability and water reduction in the fresh mix; a curing compound is sprayed on the hardened surface to retain moisture and prevent plastic shrinkage cracking and dusting. On most quality pours you benefit from both. Space Arc supplies superplasticisers, curing compounds and release agents together so site teams have a complete admixture and finishing kit.
Tell us the mix — we will name the dose.
Send your grade, cement type, placing temperature and haul time. You get a family, a working dosage range and a trial-mix recommendation, with material and technical support.