Liquid polycarboxylate superplasticizer is supplied at different concentrations for concrete production and admixture formulation. Before comparing products or preparing a diluted solution, it is necessary to understand what the stated solids content and dosage actually represent.
A dosage of 1% does not describe the same addition when one product contains 20% solids and another contains 40% solids. The comparison also changes when the percentage is calculated against cement alone rather than total cementitious materials.
This guide explains how to calculate liquid PCE dosage, convert between supplied-product and solids-based addition rates, and account for water introduced during dilution. All numerical examples are illustrative calculations, rather than recommended application dosages.
1. What Does PCE Solid Content Mean?
The solids content of a liquid PCE product describes the mass proportion remaining after testing under a specified drying procedure.
For example, a liquid product with a stated solids content of 40% contains approximately:
40 kg of measured solids per 100 kg of product.
60 kg of water and any other volatile constituents per 100 kg of product.
For the calculations below, the liquid is assumed to be an aqueous formulation in which the non-solids portion is water.
The test method matters. When comparing suppliers or checking incoming material, confirm that the solids values were determined using comparable procedures.
Measured solids should also not automatically be treated as pure active PCE polymer. A formulated admixture may contain other nonvolatile ingredients. Solids content provides a concentration reference, but it does not fully describe composition or concrete performance.
2. Define the Dosage Basis Before Calculating
A useful dosage statement needs to identify both the material being added and the reference mass.
The added material might be:
Liquid PCE as supplied.
A diluted working solution.
Solids contained in the liquid product.
The reference mass might be:
Cement only.
Total cementitious materials, including cement and supplementary cementitious materials.
For example, consider a concrete mixture containing:
| Cementitious material | Quantity |
|---|---|
| Cement | 300 kg/m³ |
| Fly ash | 60 kg/m³ |
| Ground granulated blast-furnace slag | 40 kg/m³ |
| Total cementitious materials | 400 kg/m³ |
An addition of 1% by cement mass gives:
300 × 1% = 3 kg/m³
An addition of 1% by total cementitious material mass gives:
400 × 1% = 4 kg/m³
Both calculations use 1%, but the actual product additions differ. Trial records and supplier instructions should therefore state the reference basis explicitly.
3. How to Calculate Liquid PCE Dosage
When dosage is expressed as a percentage of total cementitious materials:
Liquid product addition = Total cementitious material mass × Dosage (%) ÷ 100
For a mixture containing 400 kg/m³ of cementitious materials and an illustrative liquid-product dosage of 0.8%:
Liquid product addition = 400 × 0.8 ÷ 100 = 3.2 kg/m³
This is the mass of liquid product added to one cubic metre of concrete.
It does not mean that the mixture receives 3.2 kg of PCE solids. The solids addition depends on the concentration of that liquid.
If the product contains 40% solids:
Solids addition = 3.2 × 0.40 = 1.28 kg/m³
The corresponding solids-based dosage is:
1.28 ÷ 400 × 100 = 0.32%
A complete trial entry would therefore identify a liquid-product dosage of 0.8% and a calculated solids-based dosage of 0.32%, both relative to total cementitious materials.
4. Converting Between Product Dosage and Solids Dosage
When both dosages use the same cementitious material reference:
Solids dosage (%) = Liquid-product dosage (%) × Solids mass fraction
To calculate in the opposite direction:
Liquid-product dosage (%) = Solids dosage (%) ÷ Solids mass fraction
For an illustrative target of 0.20% solids by total cementitious material mass:
| Liquid product solids content | Calculated liquid-product dosage |
|---|---|
| 20% | 1.00% |
| 30% | Approximately 0.67% |
| 40% | 0.50% |
| 50% | 0.40% |
These values represent equivalent calculated solids additions.
They do not establish equivalent water reduction, slump retention, setting behavior or strength. Different products can contain different polymer structures and formulation ingredients, even when their measured solids content is the same.
Concentration conversion is a starting point for comparison. Concrete trials are still required to determine a suitable application dosage.
5. How to Calculate Water Addition for PCE Dilution
For straightforward dilution with water, the calculation is based on conserving the mass of solids.
Concentrate mass × Initial solids fraction = Final solution mass × Target solids fraction
Therefore:
Final solution mass = Concentrate mass × Initial solids fraction ÷ Target solids fraction
Water to add = Final solution mass − Concentrate mass
For example, suppose 1,000 kg of a 50% solids aqueous PCE concentrate is diluted to 20% solids.
The concentrate contains:
1,000 × 0.50 = 500 kg of solids
The required final solution mass is:
500 ÷ 0.20 = 2,500 kg
The water addition is:
2,500 − 1,000 = 1,500 kg
The resulting batch contains 1,000 kg of concentrate and 1,500 kg of added water, giving 2,500 kg of solution at a calculated solids content of 20%.
This calculation assumes that no material is lost and no other ingredients are added. If additional formulation components are introduced, their mass and solids contribution must be included separately.
6. Why Dilution Ratios Need a Clear Definition
An instruction such as “dilute 1:1” can be ambiguous.
It might mean one part concentrate plus one part water by mass, or it might refer to quantities measured by volume. These approaches are not interchangeable when the concentrate and water have different densities.
For a mass-based example, mixing 100 kg of a 40% solids product with 100 kg of water gives:
Solids mass = 100 × 0.40 = 40 kg
Final solution mass = 100 + 100 = 200 kg
Final solids content = 40 ÷ 200 × 100 = 20%
Dilution instructions should state:
The starting product concentration.
The concentrate quantity.
The water quantity.
Whether quantities are measured by mass or volume.
The intended final concentration.
Mass-based records provide a direct basis for checking the solids balance.
7. Adjusting Product Dosage After Dilution
Dilution reduces the solids delivered by each kilogram of liquid.
Suppose a 40% solids product is used at an illustrative addition of 2 kg/m³:
Solids addition = 2 × 0.40 = 0.8 kg/m³
After dilution to 20% solids, the calculated product quantity needed to deliver the same solids mass becomes:
0.8 ÷ 0.20 = 4 kg/m³
| Item | Before dilution | After dilution |
|---|---|---|
| Product solids content | 40% | 20% |
| Liquid addition | 2 kg/m³ | 4 kg/m³ |
| Calculated solids addition | 0.8 kg/m³ | 0.8 kg/m³ |
| Water carried by the liquid | 1.2 kg/m³ | 3.2 kg/m³ |
The diluted solution introduces 2 kg/m³ more water at the equivalent solids addition.
Dosing settings and the concrete water balance therefore need to be reviewed together. Keeping the original liquid addition after dilution would reduce the solids delivered to the mixture.
8. Accounting for Water Introduced by Liquid PCE
Water carried by an aqueous admixture contributes to the total water entering the concrete.
For the simplified aqueous formulations used here:
Water from liquid admixture = Liquid admixture mass × (1 − Solids fraction)
If a concrete mixture receives 4 kg/m³ of a 20% solids solution:
Water from admixture = 4 × 0.80 = 3.2 kg/m³
Where the mix calculation includes this contribution, it should be accounted for alongside aggregate moisture, absorption and water introduced by other liquid admixtures.
For a simplified example with 400 kg/m³ of cementitious materials and a target water-to-binder ratio of 0.40:
Target total water = 400 × 0.40 = 160 kg/m³
If the PCE solution contributes 3.2 kg/m³ of water and no other water corrections apply:
Separately added water = 160 − 3.2 = 156.8 kg/m³
Actual production calculations must also address aggregate moisture and absorption using the plant’s established mix-design procedures.
9. Converting Between Kilograms and Litres
A dosing system may meter liquid by volume, while product recommendations are stated by mass.
The conversion requires the density of the actual solution being used:
Volume (L) = Mass (kg) ÷ Density (kg/L)
For an illustrative liquid density of 1.10 kg/L, a 4 kg addition corresponds to:
4 ÷ 1.10 = Approximately 3.64 L
Density should be checked for the supplied or diluted product at the relevant temperature. Dilution changes the solution concentration and can change its density.
After changing concentration, verify the dosing equipment’s calibration and delivery accuracy before routine production.
10. What to Record During Dilution and Trial Mixing
A calculation is useful only when the batch can be traced and reproduced.
| Record item | Information to include |
|---|---|
| Starting material | Product name, batch number and measured solids content |
| Dilution quantities | Concentrate mass and water mass |
| Final solution | Total mass, calculated concentration and measured density |
| Preparation | Water source, mixing procedure and preparation date |
| Concrete dosage | Product addition and reference basis |
| Water correction | Water contributed by the admixture solution |
| Trial conditions | Concrete materials, proportions and temperature |
| Performance | Workability, retention, stability, air content, setting and strength as required |
Use dilution water and preparation procedures suitable for the product, following supplier guidance.
After preparation, check that the solution is uniform and assess any unexpected separation, precipitation or other changes before use. The storage period of a diluted formulation should be confirmed rather than assumed to match that of the concentrate.
11. Frequently Asked Questions
Does higher PCE solids content mean stronger water reduction?
Solids content indicates concentration. It does not independently determine water-reducing performance.
Product chemistry, dosage, cementitious materials and concrete conditions also affect the result. Products should be compared through controlled trials with a clearly stated dosage basis.
Can the same percentage dosage be used after dilution?
The same percentage of diluted liquid delivers less solids than the same percentage of concentrate. Recalculate the liquid quantity and water contribution before testing.
Can solids content be calculated from density alone?
Density should not replace a solids-content test unless a validated relationship has been established for that specific formulation over the relevant conditions.
Does equivalent solids dosage guarantee equivalent concrete performance?
No. Equivalent solids dosage establishes a common calculation basis, but different formulations may perform differently.
What information helps when requesting liquid PCE?
Provide the intended application, required concentration, cementitious materials, mix proportions, current dosage basis, target workability, working period and typical concrete temperature.
12. Preparing a Clear PCE Requirement
A clear purchasing or trial requirement connects concentration with the intended production process.
Instead of requesting only a liquid PCE percentage, identify whether the product will be used directly, diluted or incorporated into a formulated admixture. State whether dosing is controlled by mass or volume and whether the application dosage refers to cement or total cementitious materials.
Shenyang Xingzhenghe Chemical Co., Ltd. supplies polycarboxylate superplasticizer products for concrete applications. When discussing a sample or supply requirement, providing the concentration target and concrete trial conditions helps establish a clear basis for product evaluation.
Accurate dosage and dilution calculations support consistent trials. Final selection should be based on the concrete’s measured performance under representative production conditions.
