Sika Plastiment BV-40
A dual-action lignosulfonate admixture that reduces mix water and densifies the concrete matrix, giving watertight, durable structural concrete to IS 9103 and IS 2645.
What is it?
A modified-lignosulfonate liquid admixture from Sika that does two jobs in one dose: it reduces water demand (plasticiser) and improves the integral waterproofing of concrete, conforming to IS 9103, IS 2645 and ASTM C494.
Where is it used?
Structural concrete where watertightness, surface finish and durability matter: RCC substructures, water-retaining members, precast, piling and general site or RMC concrete across Delhi NCR and Pan-India.
Why use it?
It lets you cut mix water without losing workability, so you get a denser, less permeable, stronger concrete while keeping setting times essentially unaffected and saving cement.
How is it applied?
Dosed at 0.2-0.5% by weight of cement into the mixing water or into the mixer after 50-70% of the water is in; never onto dry cement or aggregate. Mix wet for at least 60 seconds.
About Sika Plastiment BV-40
Sika Plastiment BV-40 is one of the workhorse admixtures on Indian sites: a modified-lignosulfonate liquid that behaves both as a water-reducing plasticiser and as an integral waterproofing compound. In practical terms, a single dose lets a batching plant or site mixer either hold workability while dropping the water content, or hold the water content while gaining slump. Either way the water-to-cement ratio comes down, and a lower w/c ratio is the single most reliable lever an engineer has for denser, stronger, less permeable concrete. Because it conforms to IS 9103 (concrete admixtures) and IS 2645 (integral waterproofing compounds), specifiers can call it up on both counts in one line item.
What separates BV-40 from a plain plasticiser is that Sika has formulated it so setting times stay essentially unaffected at normal dosages, which is a genuine advantage over older lignosulfonate retarders that dragged out the set. It is a dark brown liquid supplied in 275 kg HDPE barrels, chloride-free in effect on embedded steel, and compatible with all common cements and blended cementitious systems. On a busy pour the appeal is straightforward: better finish, tighter concrete, some cement economy, and no surprise on stripping times. It is a proven, economical choice rather than a high-range performance admixture, and it is best understood in that light.
The technical insight
The mechanism is dispersion. Cement grains carry surface charges that make them flocculate the moment they meet water, trapping mixing water inside the clumps where it cannot lubricate the mix. The lignosulfonate molecules in BV-40 adsorb onto the cement particles and impose a like charge on them, so the grains repel each other and the flocs break apart. That releases the trapped water back into the system, which is why the same slump can be reached with 5-10% less water, or the same water gives a wetter, more workable mix. Lowering the water-to-cement ratio directly reduces the volume of capillary pores left behind when the excess water evaporates, and it is that capillary network that lets water track through hardened concrete. Fewer, finer, less-connected capillaries mean lower permeability, which is the integral-waterproofing half of the product doing its work, plus the strength and durability gains that always follow a tighter w/c ratio. Because the dispersion is largely physical and the dosage is modest, the effect on the cement hydration clock is small, so setting times hold roughly steady rather than being pushed out.
Where it is used
- Reinforced concrete substructures, rafts, footings and retaining walls where watertightness is required
- Water-retaining and water-excluding structures such as tanks, basements and sumps
- Piling and bored-pile concrete needing good flow and cohesion
- Precast concrete elements where surface finish and consistent quality matter
- Ready-mix and site-batched structural concrete for general building work
- Pours using poor or marginal local aggregates that benefit from added workability
- Concrete with exposed or fair-faced surfaces where blowholes and finish are a concern
- Mixes where a modest cement saving is targeted without dropping strength
Key advantages
- Improves workability at the same water content, easing placing and compaction
- Reduces water demand (typically 5-10%) without losing slump, lowering the w/c ratio
- Densifies the matrix for watertight, lower-permeability concrete under IS 2645
- Raises strength and durability as a direct result of the reduced w/c ratio
- Leaves setting times essentially unaffected at normal dosages, so stripping schedules hold
- Improves surface finish and reduces blowholes on exposed faces
- Allows a measure of cement economy for the same performance
- Compatible with all common cements and blended cementitious materials
Limitations & considerations
- A normal-range water reducer, not a superplasticiser; do not expect PCE-level slump retention or very low w/c ratios from it
- Overdosing can extend both initial and final setting times
- Excess water or overdosing can trigger bleeding or segregation
- Site trials are needed to fix the exact dose for a given mix, aggregate and cement
- Must not be added to dry cement or aggregate, and needs a minimum 60-second wet mix
- If frozen or precipitated it must be thawed slowly and remixed thoroughly before use
Selection & best practice
Fix the working dosage by trial rather than by rule of thumb: run site trials across the 0.2-0.5% by weight of cement range with your actual cement and aggregate, and settle on the lowest dose that hits your target slump and strength. Add BV-40 into the mixing water, or into the mixer once 50-70% of the water is already in; never dispense it onto dry cement or aggregate, where it cannot disperse. Give the batch at least 60 seconds of wet mixing so the admixture is fully distributed, and stir the drum before drawing product. Guard against the two classic failures at once by not overdosing (which stretches setting times) and not chasing slump with extra water on top of the admixture (which brings on bleeding and segregation). Store barrels between +10°C and +40°C, out of direct sun and frost, and use within the 12-month shelf life; if a barrel has frozen, thaw it slowly at room temperature and mix intensively before dispensing.
Specifications
| Chemical base | Modified lignosulfonates |
| Appearance / colour | Dark brown liquid |
| Density | ~1.18 kg/litre (at 25°C) |
| pH value | ≥ 6 |
| Recommended dosage | 0.2% to 0.5% by weight of cement |
| Standards | IS 9103, IS 2645, ASTM C494/C494M-99a |
| Packaging | 275 kg HDPE barrel |
| Shelf life | 12 months from production, in sealed original packaging |
| Storage | +10°C to +40°C, protected from sunlight, frost and contamination |
Industry use cases
Basements & Water-Retaining Structures
Used in raft, wall and slab concrete for basements, tanks and sumps to lower permeability and deliver watertight construction under IS 2645.
Ready-Mix Concrete Plants
A cost-effective plasticiser for general structural RMC, improving placeability and finish while trimming water and a little cement across large volumes.
Piling & Foundations
Gives bored-pile and foundation concrete the cohesion and flow needed for clean placement around congested reinforcement.
Precast Yards
Helps precast elements achieve consistent workability, a cleaner fair-faced finish and reliable strength for repeatable production.
Building Superstructure
Improves workability and surface quality of columns, beams and slabs on general building sites without disturbing stripping schedules.
Frequently asked questions
Is Sika Plastiment BV-40 a waterproofing compound or a plasticiser?
What is the correct dosage?
Will it delay setting or affect stripping times?
How is it added to the mix?
Is it safe with reinforcement, and is it chloride-based?
How is it packed, and what is the shelf life?
How we position Sika Plastiment BV-40
Plastiment BV-40 is Sika’s economical, dual-action water reducer and integral waterproofer for everyday structural concrete. Where a project needs high-range water reduction, longer slump retention or self-compacting flow, step up within the Sika family to a Sika ViscoCrete PCE superplasticiser; where the priority is purely surface or crystalline waterproofing rather than an admixture, look at Sika’s waterproofing coatings and Sika WT range instead. Across our other brands, the closest like-for-like alternative is Fosroc Conplast WL, an integral waterproofing cum water-reducing admixture built on the same lignosulfonate chemistry and the same IS 2645 basis. Space Arc supplies BV-40 and its Sika and Fosroc counterparts across Delhi NCR and Pan-India, and our technical team can help match the right admixture to your mix design.
Fosroc Conplast WL — Choose Conplast WL when the project is already standardised on Fosroc admixtures or specifies its IS 2645 integral-waterproofing performance, as it offers the same lignosulfonate water-reducing plus waterproofing action.
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