PCE vs Naphthalene Superplasticizer: How to Compare Cost per Cubic Metre
PCE costs more per tonne than naphthalene almost everywhere. That number has decided a lot of tenders that should have gone the other way. Here is the comparison that actually reflects what leaves your plant.
Short answer: compare the two at cost per cubic metre of finished concrete, not price per tonne of admixture. You need four numbers from your own plant — saturation dosage, delivered price per kilogram, cement saved per cubic metre, and your cement price. Anything less is guesswork.
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Why price per tonne misleads
A naphthalene quote and a PCE quote are not prices for the same thing, even though both are a liquid in a drum or an IBC. Three differences break the comparison:
- Dosage differs. Polycarboxylate admixtures typically reach their water-reducing effect at a markedly lower addition rate than naphthalene products. Buying fewer kilograms per cubic metre changes the arithmetic even when the price per kilogram is higher.
- Water reduction differs. More water reduction means you can cut cement while holding the same strength — and cement is by far the most expensive ingredient in the mix. A product that costs slightly more can be cheaper once you price the cement it saves.
- Behaviour on site differs. Slump retention, pumping behaviour and sensitivity to cement variation all affect how many loads get rejected or re-tempered. Those losses are real money and they never appear on the admixture invoice.
Two products can differ by 30% on price per tonne and still land within a few percent of each other on cost per cubic metre. That is why the per-tonne number keeps producing the wrong decision.
The four numbers you need
All four have to come from your materials and your prices. Published figures from a supplier's data sheet are a starting point for a trial, not an input to a purchase decision.
| Number | How to get it | Why it matters |
|---|---|---|
| 1. Saturation dosage (kg/m³) | Dose-response trial at two or three addition levels; take the point where extra admixture stops adding workability | Turns a price per tonne into a cost per cubic metre |
| 2. Delivered price per kg | Landed cost including freight, duty and local handling — not the ex-works price | Freight on a liquid admixture is a meaningful share of landed cost |
| 3. Cement saved (kg/m³) | Trial at equal slump: the cement you can remove while holding target strength | Usually the largest single term in the comparison |
| 4. Your cement price per kg | Your current delivered cement price, local currency | Converts the cement saving into money |
The calculation
The comparison is three lines of arithmetic. Use your own figures rather than anyone else's:
- Admixture cost per m³ = saturation dosage (kg/m³) × delivered price per kg
- Cement saving per m³ = cement removed (kg/m³) × cement price per kg
- Net admixture cost per m³ = line 1 − line 2
Compare the third line between the two products. Where your plant also spends money on rejected loads, site re-tempering or pumping delays, add a fourth term for that — it is usually the deciding factor in hot climates with long haul times.
Note that the cement saving only counts if the specification allows you to reduce cement content. On a fixed mix design that the client has already approved, the saving may stay with the client rather than with you — in which case compare on line 1 plus any rejection cost reduction instead.
The costs that never appear on the quote
These rarely make it into a spreadsheet, and they are often where the real difference sits:
- Rejected loads. A load refused at site costs the full batch plus disposal and a second trip.
- Re-tempering. Water added on site to restore slump quietly removes the strength margin you specified.
- Pumping time. Poor retention raises pump pressure and slows placement, which costs crew hours.
- Trial and changeover. Switching admixture costs lab time and a short period of instability; price that in if you switch often.
- Storage and handling. Different products have different shelf lives and temperature limits in a tropical yard.
When naphthalene wins, when PCE wins
| Situation | Usually the better fit | Why |
|---|---|---|
| Long haul, hot climate, slow placement | Polycarboxylate (PCE) | Retention is the limiting factor, and PCE holds workability longer |
| Short haul, general ready-mix | Naphthalene (SNF) | Retention is not binding, so the lower price per tonne wins |
| Price-driven tender on a fixed mix | Naphthalene (SNF) | No cement saving available to offset the higher admixture price |
| High strength or low water-cement ratio | Polycarboxylate (PCE) | Reaches low water contents that are impractical with naphthalene |
| Self-compacting concrete | Polycarboxylate (PCE) | Flow and stability without segregation |
| Precast with heat curing | Polycarboxylate (PCE) | Early strength development supports faster demoulding cycles |
| Cement source changes frequently | Naphthalene (SNF) | Broader tolerance; PCE needs re-testing when cement changes |
| High silt or clay content in sand | Naphthalene (SNF) | Clay can consume PCE and destroy its cost advantage |
The last two rows catch people out. PCE is the better product on paper and can still lose on cost if your sand carries clay or your cement keeps changing — which is common in fast-growing markets where daytime slump loss is already a daily fight.
How to run an honest side-by-side trial
The mistake most plants make is comparing one batch of each and reading the slump cone once. Two things make the result trustworthy:
Compare in both modes
- Equal slump. Hold workability constant and see how much cement each product lets you remove. This is the comparison most ready-mix producers want.
- Equal water–cement ratio. Hold cement constant and see what strength or workability each product delivers. This is what precast and high-strength producers want.
Run it at plant conditions
- Use production cement, aggregates and water — not laboratory materials.
- Batch at the temperature your plant actually reaches at midday.
- Test at more than one dosage so you find saturation, not just a workable dose.
- Measure at 5, 30, 60 and 90 minutes so retention is visible rather than assumed.
- Record concrete temperature at each reading.
- Keep retained cement and admixture samples — if the cement changes mid-trial you will need to separate a compatibility shift from a genuine product difference.
Half a day of this gives you two defensible numbers instead of an argument about price per tonne.
If you send us your mix design, cement brand, haul time and cement price, we will run the comparison with you and tell you honestly which grade is likely to win — including the cases where naphthalene is the right answer. Send your mix details.
Frequently asked questions
Why is comparing superplasticizers by price per tonne wrong?
Because the products are dosed at different rates and achieve different water reduction. A product that costs more per tonne can cost less per cubic metre if it needs a lower addition rate, or if the extra water reduction lets you cut cement. Only the cost per cubic metre of finished concrete tells you what you are actually paying.
What numbers do I need to compare PCE and naphthalene properly?
Four: the saturation dosage of each product on your mix in kilograms per cubic metre, the delivered price per kilogram of each product, the cement you save per cubic metre at the water reduction each product achieves, and your local cement price. Add a fifth where you can — the cost of downtime, rejected loads and site re-tempering, which rarely shows up in a mix design spreadsheet.
Should the trial compare at equal slump or equal water-cement ratio?
Run both, because they answer different questions. Comparing at equal slump shows the cement saving available at constant workability, which is what most ready-mix plants optimise for. Comparing at equal water-cement ratio shows the strength or workability gain available at constant cement content, which is what precast and high-strength producers care about.
Is naphthalene still worth using?
Yes, in the right application. Naphthalene grades remain the economical choice for short haul distances, general ready-mix, mass concrete and price-driven tenders where slump retention is not the limiting factor. They are also more tolerant of cement variation, which matters where cement sources change frequently.
Can we blend PCE with naphthalene?
Some plants do blend the two to balance cost and retention, but compatibility is not guaranteed and the result depends on your cement and the specific grades involved. Treat any blend as a new mix that needs its own trial rather than a shortcut that skips testing.
Scope of this article
This is general guidance on comparing admixture economics, not a specification or a price commitment. Dosage, water reduction and cement savings depend entirely on your cement, aggregates, mix design and plant conditions — measure them yourself rather than relying on any published figure, including ours. Product performance data elsewhere on this site comes from 2025 third-party inspection reports on standard-type samples and is not a batch guarantee; confirm batch values on the COA shipped with each order.
Which Grade Wins on Your Mix?
Send us your mix design, cement brand, haul time and cement price. We will work through the comparison with you and ship samples of both grades for a side-by-side trial.