Site investigation · Laboratory: soil classification
Fines content by washing calculator
Percentage finer than 75 µm from the dry mass before and after washing plus dry sieving of the residue.
Standard: AS 1289.3.6.1 (wash) · ASTM D1140
Open the live calculator → All site investigation calculators
Inputs in the worked example
The live calculator starts with these values; change any of them and every result, check and diagram updates instantly.
| Input | Value | Unit |
|---|---|---|
| Total dry mass before washing | 512.4 | g |
| Dry mass retained after washing | 371.8 | g |
| Mass passing 75 µm on dry re-sieve (pan) | 2.6 | g |
| Specification max fines | 30 | % |
Worked example — results
| Result | Value | Unit |
|---|---|---|
| Mass finer than 75 µm | 143.2 | g |
| Fines content | 27.95 | % |
| Fine / coarse grained (AS 1726) | coarse grained |
- ✓ Fines ≤ specification
Method, formulas and assumptions
- Mass finer than 75 µm = 512.4-371.8+2.6 = 143.2 g
- Fines content = 100*143.2/512.4 = 27.947 %
- Fine / coarse grained (AS 1726) = IF(27.947>35,"fine grained","coarse grained") = coarse grained
Related site investigation calculators
- Specific gravity (pycnometer) — Two-trial lab sheet for soil particle density with temperature correction to 20 °C and repeatability check.
- Particle size distribution — Sieve masses to % passing, grading curve, D10/D30/D60, Cu, Cc and a USCS group symbol.
- Hydrometer analysis — Fine-fraction grading from hydrometer readings: particle diameter by Stokes' law and percent finer.
- Atterberg limits & plasticity chart — Liquid limit from cone penetrometer or Casagrande points, PI, liquidity index and position on the plasticity…
- Moisture, density & phase relations — Bulk and dry density, void ratio, porosity, saturation and field density ratio, with a three-phase diagram.
- Moisture content (oven drying) — Moisture content of several specimens from tin masses, with mean, range and repeatability check.
- Liquid limit: cone penetrometer — Linear fit of moisture content against cone penetration; the liquid limit is w at 20 mm penetration.
- Liquid limit: Casagrande cup — Flow curve (w against log N) by least squares; LL at 25 blows and the flow index.
- Liquid limit: one-point method — LL from a single Casagrande reading using LL = wN (N/25)^0.121, valid for 20–30 blows.
- Plastic limit & consistency indices — PL from repeat threads, PI, liquidity and consistency index, activity and plasticity chart class (A-line).
For preliminary design and education. Check every result against the current standard and your own engineering judgement before use.