This standard specifies the laboratory methods for determining the specific gravity of soil solids. It covers procedures for both fine-grained soils (using a pycnometer or density bottle) and coarse-grained soils (using a gas jar). This fundamental soil property is essential for calculating phase relationships like void ratio and degree of saturation.
Specifies methods for determining the specific gravity of soil particles, applicable to both fine-grained and coarse-grained soils.
Quick Reference Values
Standard reporting temperature27 °C
Accuracy of weighing balance0.001 g for fine-grained soils
Pycnometer/Density Bottle capacity50 ml for fine-grained soils
Typical G for sand (inorganic)2.65 - 2.68
Typical G for clay (inorganic)2.70 - 2.80
Minimum mass of soil for fine-grained soil test25 to 50 g
Key Formulas
G = (M2 - M1) / [ (M4 - M1) - (M3 - M2) ] — Specific Gravity at test temperature T°C
G_27°C = Kt * G_T°C — Specific Gravity corrected to standard temperature 27°C
Practical Notes
Complete removal of entrapped air by vacuum is the most critical step; insufficient de-airing leads to erroneously low specific gravity values.
Applying the temperature correction factor (Kt from Table 1) to normalize the result to the standard 27°C is mandatory for reporting.
The code is split into two sections within Part 3: Section 1 for fine-grained soils and Section 2 for coarse-grained soils, which require different apparatus sizes and sample quantities.