Technical selection guide
Superplasticizer Dosage in Concrete
Calculate the quantity from an explicitly defined dose and binder basis. The calculation converts a trial instruction into mass or volume; it does not select an approved dosage for your concrete.
Updated 2026-09-18
Define both sides of the percentage
Write the instruction in full: mass of supplied product ÷ mass of the specified cement or binder × 100. If the document instead specifies a solids-based dose, keep that basis visible. Confirm whether the denominator includes supplementary cementitious materials.
| Quantity | Calculation | Input to verify |
|---|---|---|
| Supplied-product mass | Reference mass × supplied-product dose (%) ÷ 100 | Cement or total binder as specified; not an assumed interchange. |
| Declared solids mass | Supplied-product mass × declared solids fraction | The grade’s solids content and test method. |
| Product mass from a solids target | Required declared solids mass ÷ solids fraction | Nonzero solids fraction for the selected product. |
| Liquid volume | Product mass ÷ product density | Consistent kg and kg/L units; density for the actual grade. |
| Carrier-water estimate | Product mass × confirmed water fraction | Composition evidence; the entire non-solids fraction is not automatically water. |
Total solids and active PCE polymer are not automatically the same quantity. Ask which is reported before comparing two specifications. The composition converter provides a transparent calculation; use its active-solids interpretation only when the product information supports it.
Worked example: product, solids and volume
Invented inputs for arithmetic only: 400 kg of total binder; a specified supplied-product dose of 0.50%; declared solids of 40%; assumed density of 1.10 kg/L. These are not AdmixChem specifications or a recommended trial dose.
Product mass = 400 × 0.50 ÷ 100 = 2.00 kg.
Declared solids = 2.00 × 0.40 = 0.80 kg, or 0.20% of binder.
Liquid volume = 2.00 ÷ 1.10 = approximately 1.82 L.
The remaining mass is 1.20 kg; treat it as water only if the confirmed composition supports that assumption.
If the 400 kg binder includes 320 kg cement and 80 kg supplementary material, the same 2.00 kg product is 0.625% of cement mass but 0.50% of total binder. Both calculations can be correct while answering different questions.
Use one record for each candidate trial
| Record | What to enter |
|---|---|
| Product identity | Grade, batch, TDS revision, supplied form and declared concentration. |
| Reference materials | Cement and supplementary materials, aggregate source and other admixtures. |
| Dose instruction | Mass or volume; cement/binder denominator; supplied-product or solids basis. |
| Water accounting | Batch-water entry, aggregate-moisture correction and documented liquid contributions. |
| Conditions | Concrete temperature, mixing sequence and observation times used by the test team. |
| Results and disposition | Recorded workability, air, setting and strength observations; reviewer and next action. |
The NRMCA quality-control guide supports documented materials and process control. Use the compatibility checklist when trial results change unexpectedly. The project’s responsible technical team defines test methods and acceptance criteria.
Questions buyers ask
How many kilograms are needed per tonne of cement?
For a dose d expressed as supplied-product mass percent of cement, the calculation is 10 × d kg per tonne of cement. For example, an explicitly specified 0.50% gives 5 kg. This is a unit conversion, not a dosage recommendation.
Can I use litres instead of kilograms?
Yes for quantity conversion when the current product density is known: litres = kilograms ÷ density in kg/L. Do not assume that one litre equals one kilogram.
What if the dose is based on total binder?
Use the defined total binder mass. Do not silently substitute cement mass or the total wet concrete mass.
Does increasing dose guarantee better flow?
The arithmetic cannot predict the mixture response. Select any trial range from the applicable grade document and technical evaluation rather than extend it from a calculation.
Calculate a documented trial quantity
Have the reference mass, dose basis and concentration ready. Save the inputs with the result so another person can reproduce it.
Apply the documented dose to a whole batch
When the mix is specified per cubic metre, use the concrete batch admixture calculator to scale volume and binder content into product mass. Keep the supplied-product or active-solids basis with the result; the calculation does not select a dosage.
For SSD aggregate quantities, the aggregate moisture correction calculator separates measured aggregate water from water to add. Verify each aggregate fraction and the applicable water-accounting method.