Cost · 9 min read · Updated 2026
In this article
Where the money goes
Before cutting cost, know where it sits. A typical precast mix breaks down roughly like this:
- Cement: 55–65% of total material cost
- Aggregate and sand: 20–28%
- Admixture: 8–14%
- Water and everything else: under 3%
The conclusion is unavoidable: meaningful savings have to come from cement. Negotiating 10% off your admixture price saves about 1% of material cost. Cutting cement content by 15% saves around 9%.
This is why comparing admixtures on price per litre is the wrong question. The right question is: how much cement does this product let me remove?
The principle: water saved = cement saved
Compressive strength is governed primarily by the water-to-binder ratio. By Abrams' law, lower W/C means higher strength.
Say your current mix uses 400 kg cement and 180 kg water — W/C 0.45, giving 400 ksc at 28 days.
Switch to a PCE that removes another 15% of the water and you are at 153 kg. You now have two choices:
- Keep cement at 400 kg → W/C 0.38, strength jumps to roughly 480–500 ksc. That is more than you need — you are paying for cement you are not selling.
- Cut cement until W/C returns to 0.45 → cement drops to 340 kg. You save 60 kg/m³ at unchanged strength.
In practice we rarely go all the way. A middle position — say 45 kg less cement, with the remaining strength gain kept as safety margin — is usually the right call.
A worked example
Built on the actual PCE=1 Gold 600 trial data, with illustrative material prices.
| Item | Old mix (naphthalene) | New mix (Gold 600) |
|---|---|---|
| Cement | 380 kg | 323 kg −15% |
| Water | 160 kg | 136 kg |
| W/C | 0.421 | 0.421 |
| Admixture | 4.56 L | 2.58 L |
| Cement cost @ THB 2.20/kg | 836 | 711 |
| Admixture cost | 114 | 155 |
| Total | 950 | 866 |
A saving of THB 84 per cubic metre. At 120 m³ a day over 26 days that is about THB 262,000 a month, or over THB 3.1 million a year — from the mix design alone, before counting production-cycle gains.
Note: material prices here are illustrative. Use your own.
Early strength and mould cycles
For a casting yard there is a second cost that rarely appears in any spreadsheet: the opportunity cost of your moulds. If a mould set costs THB 800,000 and you demould once a day, getting to two cycles a day doubles capacity without buying a single new mould.
The PCE=1 Gold 600 trial reached 380 ksc at 1 day against 270 ksc for the control. If your demoulding threshold is 300 ksc, the old mix is not ready at 24 hours — the PCE mix already is.
In plants with a full order book and moulds as the bottleneck, this is often worth more than the cement saving.
How to run a trial mix properly
Never move a new mix straight from paper to production. The sequence we use:
- Establish a baseline. Record the current mix, actual slump, and 1/7/28-day strength for at least 20 past batches so you know the mean and standard deviation.
- Test the materials. Sand fineness modulus, clay content, moisture, aggregate grading, and the cement type and brand.
- Flush the dosing system. Tanks, pump and lines clear of the previous admixture. Do not skip this.
- Lab trial first. Screen three or four dosage rates and measure slump at 0/30/60/90/120 minutes.
- Full batch trial. Produce one real batch, cast cylinders, and follow strength at 1, 7 and 28 days.
- Adjust and confirm. Repeat over at least three batches before it becomes the standard mix.
Five mistakes plants make
- Not flushing the dosing system. The number-one reason a trial "shows nothing".
- Dosing with the first water. PCE performs best with delayed addition, after some water and cement have already mixed — it avoids excessive adsorption by C₃A.
- Not correcting for sand moisture. At low W/C, sand 1% wetter than assumed can ruin a batch.
- Cutting cement too aggressively at once. Step down 5% at a time and confirm — do not attempt 20% in the first trial.
- Not keeping records. Without historical data you can never tell whether the new mix is genuinely better or you simply got a good week.
If you would like our engineers to plan and run the trial at your plant, reach us on Line @PCE1 or call +66 82-700-5937. The service is free of charge for producers evaluating a change of mix design.