Mastering the Sieve Analysis Wash Method: Reliable Results Every Time

Sieve Analysis Wash Method (ASTM D1140)

Purpose Sieve Analysis Wash Method

The Sieve Analysis Wash Method is employed to accurately determine the percentage of soil particles finer than the 75-µm (No. 200) sieve. This wet sieving technique is particularly effective for soils containing a significant amount of fine particles that may adhere to coarser grains, which dry sieving might not efficiently separate.

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Equipment Required

• Balance: Sensitive to 0.1 g
• Sieve Set: Including a No. 200 (75-µm) sieve
• Wash Bottle or Gentle Water Source
• Drying Oven: Capable of maintaining 110 ± 5°C
• Evaporating Dish or Suitable Container
• Mortar and Pestle: For pulverizing soil lumps
• Dispersing Agent: Such as a 2% sodium hexametaphosphate solution (for Method B)

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Test Methods Overview

ASTM D1140 outlines two methods:

• Method A: For non-cohesive soils with little to no plasticity. The sample is soaked in water to facilitate separation.
• Method B: For cohesive soils with plastic fines. The sample is soaked in a dispersing solution to aid in disaggregation.

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Step-by-Step Procedure

1. Sample Preparation
   • Obtain a representative soil sample and dry it in the oven at 110 ± 5°C until a constant weight is achieved.
   • Record the dry mass (W₀) of the sample.
2. Soaking
   • Method A: Place the dried sample in a container and add sufficient water to cover it. Soak for at least 10 minutes.
   • Method B: Place the dried sample in a container and add a dispersing solution. Soak for at least 10 minutes to ensure thorough dispersion of fine particles.
3. Washing
   • Pour the soaked soil slurry over a nest of sieves, with the No. 200 sieve at the bottom.
   • Gently agitate and rinse the material using a wash bottle or gentle water stream.
   • Continue washing until the water passing through the sieve is clear, indicating the removal of fine particles.
4. Drying
   • Collect the material retained on the No. 200 sieve.
   • Dry the retained material in the oven at 110 ± 5°C until a constant weight is achieved.
   • Record the dry mass (W₁) of the retained material.
5. Calculation

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Significance in Geotechnical Engineering

Understanding the proportion of fine particles in soil is crucial for:

• Soil Classification: Helps in determining the soil type and its suitability for construction projects.
• Permeability Assessment: Fine particles affect the soil’s ability to transmit water.
• Compaction Characteristics: Influences the soil’s compaction behavior and stability.
• Foundation Design: Affects the bearing capacity and settlement characteristics of soils.

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Safety and Quality Considerations

• Ensure all equipment is clean and free from previous test residues.
• Handle sieves carefully to prevent damage to the mesh.
• Use appropriate personal protective equipment (PPE) when handling dispersing agents and during the drying process.

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For a visual demonstration of the Sieve Analysis Wash Method, you might find this video helpful:

Materials Finer than the No. 200 Sieve by Washing

• Category: Soil
• Tag: Sieve Analysis Wash Method