Comparison · 10 min read · Updated 2026
In this article
The comparison at a glance
| Criterion | Lignosulfonate (molasses) | Naphthalene (SNF) | PCE |
|---|---|---|---|
| Generation | 1st | 2nd | 3rd |
| Mechanism | Electrostatic | Electrostatic | Electrostatic + steric |
| Water reduction | 5–10% | 15–25% | 20–40% |
| Slump after 1 hour | Largely gone | 30–50% loss | <10% loss |
| Dosage | High | Standard | 30–50% lower |
| Early strength | Low (over-retarded) | Moderate | High (tunable) |
| Entrained air | High, hard to control | Moderate | Low, evenly distributed |
| Price per litre | Lowest | Mid | Highest |
| Cost per m³ | Mid–high | Mid | Lowest |
Mechanism: where they diverge
Lignosulfonate and naphthalene work the same way: they coat cement particles in negative charge so like charges repel. It works — at first. But it carries a flaw that cannot be engineered out: the moment cement starts reacting with water it releases calcium ions that neutralise the adsorbed charge.
From the second the mix leaves the plant, a clock is running. Hot weather, finer cement and higher C₃A all make that clock run faster.
PCE adds a second, purely physical mechanism — steric hindrance from PEG side chains — which is indifferent to the ionic state of the pore solution. Manufacturers can also design part of the polymer to release gradually, so fresh dispersing power keeps arriving over the first hours.
Slump retention: the invisible cost
This matters more than most people account for, because when concrete arrives on site with low slump, what actually happens is that someone adds water.
Adding 10 litres per cubic metre to a mix with 320 kg of cement raises W/C by roughly 0.03. By Abrams' law that costs you somewhere around 8–12% of compressive strength. A mix designed for 320 ksc can arrive as 285 ksc concrete.
In money: if your plant carries an extra 15 kg/m³ of cement just to absorb that uncertainty, at roughly THB 2.20/kg that is THB 33 per cubic metre. At 200 m³ a day it is THB 6,600 a day — about THB 1.7 million a year.
Strength: real trial figures
The figures below come from PCE=1 product data sheets, tested against a control mix at identical cement content.
| Product | Control (28 d) | With PCE=1 (28 d) | Change |
|---|---|---|---|
| Gold 500 | 386 ksc | 518 ksc | +34.2% |
| Gold 600 | 388 ksc | 531 ksc | +36.9% |
| Green 1333 (vs conventional retarder) | 322 ksc | 366 ksc | +13.7% |
| Red 1750C | 317 ksc | 358 ksc | +12.9% |
Note that Green 1333 is benchmarked against concrete containing a conventional retarding admixture, not against plain concrete — the fairer comparison — and still shows 13.7%. Against plain concrete the gap is 21.6%.
Early strength is just as interesting: Gold 600 reached 380 ksc at 1 day against 270 ksc for the control, a 40.7% gain. For a casting yard that translates directly into earlier demoulding and more mould cycles per day.
Working out cost per cubic metre
This is the comparison that actually decides the question. Using realistic illustrative numbers:
Case A — naphthalene admixture
- Cement 380 kg/m³ × THB 2.20 = THB 836
- Admixture at 1.2% of cement = 4.56 L/m³ × THB 25 = THB 114
- Subtotal = THB 950 / m³
Case B — PCE=1
- Cement cut 15% to 323 kg/m³ × THB 2.20 = THB 711
- Admixture at 0.8 L per 100 kg = 2.58 L/m³ × THB 60 = THB 155
- Subtotal = THB 866 / m³
A difference of THB 84 per cubic metre — even though the admixture itself costs well over twice as much per litre. And that is before counting reduced rejects, less surface patching and faster production cycles.
Caveat: these numbers illustrate the method, not your plant. Cement and admixture prices differ, and the cement reduction you can actually achieve depends on your materials. Have your supplier run a trial mix and redo this arithmetic with your real figures before deciding.
When legacy chemistry still makes sense
To be fair, there are situations where an older admixture is still the reasonable choice:
- Work with modest strength requirements and no slump-retention pressure — lean concrete, levelling and fill.
- Plants that cannot yet control aggregate moisture. PCE is more sensitive to water variation; if the weighing and moisture systems are not ready, fix that first.
- Cements that are awkward with PCE. Occasionally seen with unusually low soluble sulphate — though today this is normally solved by adjusting the PCE formulation rather than abandoning it.
For cases that genuinely need the older chemistry we keep a Black Series naphthalene-based range. But in nine out of ten plants we survey, moving to PCE is clearly the better return.