Specific Gravity of Soil (Pycnometer) — Lab Manual

Objective & standard

Specific gravity of soil solids, used for void ratio, degree of saturation and hydrometer analysis.

Standard: ASTM D854 / BS 1377-2

Apparatus

• Pycnometer / density bottle (50 or 500 ml)
• Vacuum pump or boiling
• Balance
• Distilled water, thermometer

Procedure

1. Weigh the clean dry pycnometer (W1).
2. Add about 50 g oven-dry soil (passing 4.75 mm) and weigh (W2).
3. Fill partly with distilled water, remove entrapped air by vacuum or gentle boiling for 10 min.
4. Fill to the mark, wipe dry and weigh (W3).
5. Empty, clean, fill with water only and weigh (W4). Record the temperature.

Calculations

• G = (W2 − W1) ÷ [(W2 − W1) − (W3 − W4)]
• Correct to 20 °C: G20 = G × (ρw at T ÷ ρw at 20 °C)

Typical values: Sand 2.63–2.67, silt 2.65–2.70, clay 2.67–2.80; organic soils below 2.4.

Open the Specific Gravity calculator →

Data sheet (print this page)

Project: ____________________   Sample: __________   Date: __________   Tested by: __________

🖨 Print lab sheet