Laboratory Tests

Grain size, Atterberg limits, shear strength, consolidation, compaction, CBR, and fine-soil gradation.

  • Specific gravity

    Specific gravity is a dimensionless, crucial engineering property used to determine void ratio, porosity, and degree of saturation.

  • Sieve analysis — dry

    Dry sieve analysis is a laboratory method used to determine the grain size distribution of dry, free-flowing materials (such as sand, gravel, or powders) by passing them through a stacked series of sieves with progressively smaller mesh sizes.

  • Sieve analysis — wet

    Wet sieve analysis is a laboratory technique used to accurately determine the particle size distribution of materials—particularly soils, aggregates, or powders containing significant fines (clay/silt) or that are sticky.

  • Atterberg limits

    Atterberg limits are critical water content percentages (liquid, plastic, and shrinkage) that define the boundaries between solid, semi-solid, plastic, and liquid states of fine-grained soils (clays and silts).

  • Natural moisture content

    Natural moisture content (or natural water content) is the ratio of the weight of water to the weight of solid particles in a soil sample, expressed as a percentage. It represents the actual amount of water present in the soil in its natural, field state, generally determined by oven-drying at 105 °C–110 °C.

  • Direct shear test

    The direct shear test is a laboratory method used to determine the shear strength parameters—cohesion (c) and angle of internal friction (φ)—of soil by forcing a specimen to fail along a horizontal plane. It is particularly effective for testing granular, non-cohesive soils and provides quick results for geotechnical design applications.

  • Triaxial test

    A triaxial test is a common geotechnical laboratory test used to determine the shear strength parameters (cohesion and internal friction angle) of soil—essential for designing foundations, slopes, and tunnels.

  • Consolidation test

    The consolidation test measures the rate and magnitude of soil settlement in saturated, cohesive soils under vertical pressure.

  • Hydrometer analysis

    Hydrometer analysis is a geotechnical laboratory method used to determine the particle size distribution of fine-grained soils (silts and clays) passing the #200 sieve (0.075 mm).

  • Proctor compaction test

    The Proctor compaction test is a laboratory method used to determine the maximum dry density (MDD) and optimum moisture content (OMC) of soil.

  • Free swell index test

    The free swell index (FSI) test, per IS: 2720 (Part 40), measures the increase in volume of soil (10 g, passing 425 µm sieve) upon wetting, identifying its swelling potential.

  • California Bearing Ratio (CBR) test — soaked & unsoaked

    The California Bearing Ratio (CBR) test is a penetration test used to evaluate the mechanical strength of subgrade soil and base course materials for road and pavement design.