AZA 0856 GRAIN SIZE ANALYSIS (PIPETTE METHOD)

Description

The Grain Size Analysis (Pipette Method) apparatus is a precision testing setup used to determine the distribution of fine soil particles such as clay and silt. It is widely employed in geotechnical engineering, civil construction quality control, soil mechanics research, and academic laboratories. When standard sieve analysis becomes ineffective for particles smaller than 75 microns, the pipette method provides an accurate and detailed alternative based on sedimentation principles.

This is for the determination of the sub sieve particle distribution in a soil sample by mechanical analysis. An analysis of this kind
expresses quantity the proportions by weight of the various sizes of particles present in the soil. It is recommended as a standard procedure to use dispersion agent to avoid flocculation. The apparatus consists of a sliding panel which moves up and down by means of a screw allowing Anderson pipette fixed to it to be raised or lowered vertically. A sedimentation tube is held by a laboratory clamp provided on the stand below the pipette. The depth of immersion is measured by a scale graduated in mm at the side of the sliding panel. Supplied complete with Anderson pipette 10ml. At the side capacity made from glass, and a sedimentation tube also of glass of 500ml capacity and 50nos. Test form pads.
Accessories & Spares: (on extra cost)
1) Sedimentation Pipette (Anderson pipette) 25ml.
2) Sedimentation tube 100ml
3) Sedimentation pipette 10ml
4) Sedimentation tube 500ml
5) Test forms pad of 50

This method works by measuring the rate at which different-sized particles settle in a suspension. By using Stokes’ Law and timed extraction of samples at known depths, technicians can quantify the proportion of fine particles in soil samples. The method is particularly crucial for the classification of cohesive soils and for identifying the presence of expansive clay, silt, and colloidal content that can influence a structure’s performance. AZALAB

What’s Included in the Apparatus:

1. Sedimentation Cylinder (1-liter graduated glass cylinder): Where the soil-water suspension settles.
2. Pipette Assembly (usually 10 ml): For extracting samples from specific depths at set time intervals.
3. Stand with Pipette Holder: Ensures vertical positioning and repeatable sample collection.
4. Stopwatch or Timer: Essential for tracking sedimentation intervals.
5. Mechanical Stirrer or Mixing Rod: To uniformly disperse soil particles in water.
6. Thermometer: For adjusting readings based on water temperature, as viscosity affects particle settling.

All components are made of high-quality laboratory-grade materials that ensure long-term use, easy cleaning, and resistance to chemicals used in dispersing soil.

Working Principle:

The pipette method relies on the sedimentation of soil particles in a fluid medium (typically distilled water mixed with a dispersing agent like sodium hexametaphosphate). Once the uniform suspension is formed, the soil particles start to settle due to gravity. According to Stokes’ Law, larger particles settle faster than smaller ones.

At timed intervals, a pipette is used to extract small quantities of suspension from a predetermined depth. These samples are dried and weighed, and from the known total soil mass and cumulative sample weights, the distribution of particles finer than specific sizes is calculated. AZALAB+BIS

This method is suitable for particle sizes in the range of 0.002 mm to 0.075 mm.

Applications:

• Geotechnical Investigation: Classify fine soils and assess their impact on foundation behavior.
• Soil Classification Systems: Determine Atterberg Limits and other soil indices.
• Academic Research & Education: Teach fundamental soil mechanics and sedimentation theory.
• Construction & Earthworks: Evaluate soil suitability for roads, embankments, and backfills.

Standards Compliance:

• IS: 2720 (Part IV) – Grain Size Analysis
• ASTM D422 – Standard Test Method for Particle-Size Analysis of Soils
• BS 1377 – Methods of test for soils for civil engineering purposes

Specifications Table:

Frequently Asked Questions (FAQs):

Q1: What is the purpose of the pipette method in grain size analysis?
A: It is used to determine the proportion of fine particles in soil, especially those smaller than 75 microns that can’t be captured by sieves.

Q2: What standards does this method comply with?
A: It complies with IS: 2720 (Part IV), ASTM D422, and BS 1377 standards for soil particle analysis.

Q3: Can I use this method for all types of soil?
A: It is most effective for fine-grained soils such as clays and silts. Coarser soils are best tested with sieve analysis.

Q4: Is the dispersing agent included in the kit?
A: No, chemical dispersants like sodium hexametaphosphate must be sourced separately.

Q5: How accurate is the pipette method?
A: When conducted properly, it provides highly accurate and repeatable results for fine soil particle distribution.