This standard specifies the laboratory test methods for determining the water content, density, porosity, and water absorption of rock samples. These are fundamental index properties used for the classification, characterization, and quality assessment of rock materials in civil and mining engineering projects.
Specifies methods for determining water content, density, porosity, and absorption of rock specimens.
Quick Reference Values
Oven drying temperature105 to 110 °C
Minimum drying duration24 hours
Minimum specimen mass for water content50 g
Minimum saturation duration24 hours
Balance accuracy for weighing0.01% of specimen mass
Key Formulas
Water Content, w (%) = [(M_wet - M_dry) / M_dry] * 100
Bulk Density, ρ = M / V
Porosity, n (%) = [(M_sat - M_dry) / (M_sat - M_sub)] * 100
Water Absorption, A (%) = [(M_sat - M_dry) / M_dry] * 100
Practical Notes
Ensuring complete saturation is critical for accurate porosity results; vacuum saturation is highly recommended over simple immersion.
The saturated-surface-dry (SSD) condition is a key step and requires skill to achieve correctly; a damp cloth is used to remove surface water without pulling water from the pores.
The presence of micro-fractures, which may not be part of the intergranular pore space, can significantly influence absorption and porosity values.