Admixture Dosage Rate Calculator

Input Parameters

Calculation basis

By cement mass (kg)

By concrete volume (m³) with cement content

Cement per batch (kg)

Dosage

bwoc = by weight of cement

Admixture density (kg/L) Typical range 1.02–1.15 kg/L.

Recommended min (% bwoc)

Recommended max (% bwoc)

Number of identical batches

How the calculation works

Determine cement in the batch: cement_mass = cement_per_batch_kg or volume × cement_content.
Apply the dosage:
- % bwoc: admixture_mass = cement_mass × (percent ÷ 100).
- mL per kg: admixture_volume_L = cement_mass × (mL_per_kg ÷ 1000).
- L per 100 kg: admixture_volume_L = (cement_mass ÷ 100) × L_per_100kg.
Convert mass/volume using density: volume = mass ÷ density, mass = volume × density.
Multiply by number of batches for totals.

Always confirm manufacturer recommendations and conduct trial mixes to verify performance.

Results

Within recommended band

Metric	Per batch	Total (1 batch)
Cement (kg)	350.000	350.000
Admixture mass (kg)	2.800	2.800
Admixture volume (L)	2.667	2.667

Recommended band (based on % bwoc)

Band	Mass per batch (kg)	Volume per batch (L)
Min 0.400%	1.400	1.333
Max 1.500%	5.250	5.000

Note: If using dosage units other than percent, the band comparison still uses the % bwoc values you provided to check suitability.

Assumptions and Tips

Density is product specific; consult the technical datasheet for accurate conversion between mass and volume.
For plant dosing, calibrate flow meters or pump counts to liters required per batch.
When batching by truck volume, verify actual yield and adjust cement content accordingly.
Trial mixes should confirm slump, workability retention, and strength development at the selected rate.

FAQs

1) What does % bwoc mean?

It stands for percent by weight of cement. A 1% rate equals 1 kg of admixture mass per 100 kg of cement. The tool converts between mass and volume using density.

2) Can I enter mL per kg instead of percent?

Yes. Choose mL per kg and provide the value. The calculator multiplies by cement mass and converts mL to liters. You can still set a recommended percentage band for checks.

3) What density should I use?

Use the product datasheet. Many water-reducing agents have densities around 1.02–1.15 kg/L, but specialty products may differ. Accurate density is required for mass↔volume conversion.

4) How do I use it for multiple batches or trucks?

Enter the number of identical batches. The results table reports both per-batch requirements and the total for all batches.

5) Can this estimate compliance with manufacturer limits?

Enter the recommended minimum and maximum percentages. The badge indicates whether your selected dose falls within that band for the current cement mass.

6) Does it account for water in the admixture?

No. If water content from the admixture affects water-cement ratio or slump, adjust your mix design accordingly using your internal procedures.