PARTICLE SIZE SEDIMENTATION (HYDROMETER METHOD) AZA0857

Description

Working Principle

A representative soil sample is dispersed in water using a chemical dispersing agent, typically sodium hexametaphosphate, to prevent flocculation. The suspension is transferred into a graduated sedimentation cylinder. As particles settle under gravity, larger particles settle faster while finer particles remain in suspension for longer durations.

A soil hydrometer is inserted into the suspension at specified time intervals to measure the relative density of the suspension. Using standard calculations and temperature corrections, the percentage of particles finer than specific diameters is determined. This method is suitable for particle sizes generally below 0.075 mm.

Applications

• Geotechnical investigations and soil classification
• Foundation, embankment, and earthwork design
• Soil mechanics teaching and academic research
• Civil engineering laboratory testing
• Environmental and sediment analysis (lakes, rivers, wetlands)

Standards Compliance

• IS 2720 (Part IV) – Grain Size Analysis of Soils
• ASTM D422 – Particle-Size Analysis of Soils
• BS 1377 – Methods of Test for Soils for Civil Engineering Purposes

System Composition (Complete Set)

• Sedimentation Cylinders – 1000 ml capacity, borosilicate glass (6 nos.) with rubber bungs
• Soil Hydrometer – ASTM 151H, range 0.995 to 1.038 g/ml, least count 0.001
• Glass Tank – Approx. 600 × 300 × 380 mm
• Immersion Heater with Thermostat and Circulation Unit – 230V AC, Single Phase, 50 Hz, 1000 W
• Glass Thermometer – Range –10°C to 50°C, subdivision 0.5°C
• Beaker – Borosilicate glass, 250 ml capacity
• Dispersing Agent – Sodium Hexametaphosphate, 1000 g
• High Speed Stirrer – 4000 RPM, complete with dispersion / baffle cup for soil dispersion

Technical Specifications

What’s Included

• Complete Hydrometer Analysis Setup (AZA0857)
• Soil Hydrometer (151H)
• Sedimentation Cylinders with rubber bungs
• Immersion heater with circulation unit
• Glass thermometer
• High speed stirrer with baffle cup
• Beaker and accessories as listed

Frequently Asked Questions (FAQ)

Q1: What is the hydrometer method used for?
It is used to determine the grain size distribution of fine soils such as silts and clays through sedimentation analysis.

Q2: How accurate is the hydrometer method?
It provides high accuracy for particles smaller than 75 microns, which cannot be reliably analyzed using sieve methods.

Q3: Is this method suitable for sandy soils?
No. It is specifically intended for fine-grained soils. Coarse particles settle too rapidly for accurate hydrometer readings.

Q4: Which standards does AZA0857 comply with?
The apparatus conforms to IS 2720 (Part IV), ASTM D422, and BS 1377.

Q5: Is the dispersing agent included?
Yes. Sodium hexametaphosphate is supplied with the complete AZA0857 set.