Methods of test for stabilized soils, Part 3: Test for determination of moisture content-dry density relation for stabilized soil mixtures

IS 4332 Part 3: Scope & Key Specifications

This part focuses on soil compaction tests with stabilizers, specifying:

• Use of compaction mould assemblies for light and heavy compaction.
• Definitions aligned with IS 2809:1972 (soil engineering terms).
• Procedures for determining wet density, dry density, moisture content, and stabilizer content.

Key Formulas:

• Dry Density (ρ_d):

[ \rho_d = \frac{\text{Weight of compacted soil stabilizer mixture}}{\text{Volume of mould} \times (1 + \frac{w}{100})} ]

where ( w ) = moisture content (%)

• Wet Density (ρ_w):

[ \rho_w = \frac{\text{Weight of mould + compacted soil stabilizer mixture} - \text{Weight of mould}}{\text{Volume of mould}} ]

• Moisture Content (w%):

[ w = \frac{\text{Weight of water}}{\text{Weight of dry soil}} \times 100 ]

Sample Report Table (Clause 8.1):

flowchart TD
    A[Soil Sample + Stabilizer] --> B[Compaction Mould Assembly]
    B --> C[Compaction Test (Light/Heavy)]
    C --> D[Measure Weights & Volume]
    D --> E[Calculate Wet & Dry Density]
    E --> F[Report Results]

Summary: IS 4332 Part 3 standardizes soil compaction testing with stabilizers, emphasizing measurement of densities, moisture, and stabilizer content using specified moulds and procedures.

IS 4332 Part 3: Key References and Specifications

• Reference Standard for Definitions:
  IS 2809:1972 — Glossary of terms and symbols related to soil engineering.

• Compaction Test Specifications:

  • Use standard compaction mould assemblies as per IS specifications for light and heavy compaction tests.
  • Typical mould volume: 1000 cm³ (1 litre) for standard Proctor tests.

• Key Test Data Table (Sample):

• Dry Density Calculation Formula:
  [ \text{Dry Density} = \frac{\text{Wet Density}}{1 + \frac{\text{Moisture Content (%)}}{100}} ]

This standard relies on IS 2809 for terminology and defines procedures for soil compaction testing using specified moulds and moisture/stabilizer content measurements.

flowchart TD
    A[Prepare Soil-Stabilizer Mix] --> B[Weigh Mould + Mix]
    B --> C[Weigh Empty Mould]
    C --> D[Calculate Weight of Mix]
    D --> E[Calculate Wet Density]
    E --> F[Measure Moisture Content]
    F --> G[Calculate Dry Density]

IS 4332 Part 3: Definitions Summary

• The standard refers to IS 2809:1972 for all definitions related to soil engineering terms.
• IS 2809 provides a glossary of terms and symbols used in soil engineering, including compaction, voids, density, and moisture content.
• Key related terms often used:
  • Air Voids (V_a): The volume of air in a compacted soil mass.
  • Compaction Mould Assembly: Apparatus for light/heavy compaction tests.

Air Voids Lines Formula (Clauses 7.1.3 & 7.2.3):

[ V_a = \left(1 - \frac{G \times \rho_w}{\rho_d}\right) \times 100 ]

Where:

• ( V_a ) = Air voids percentage
• ( G ) = Specific gravity of soil solids
• ( \rho_w ) = Unit weight of water (typically 9.81 kN/m³)
• ( \rho_d ) = Dry density of the soil

Summary:

• Use IS 2809 for definitions.
• Air voids calculation is critical for compaction quality control.
• The formula helps plot air voids lines on compaction curves.

flowchart LR
    A[IS 4332 Part 3] --> B[Definitions from IS 2809]
    B --> C[Terms: Air Voids, Compaction]
    C --> D[Use Air Voids Formula]
    D --> E[Calculate V_a for compaction control]

IS 4332 Part 3: Apparatus for Moisture Content Determination

• Apparatus must comply with IS 4332 (Part II) 1967.
• Typical equipment includes:
  • Moisture oven capable of maintaining 110 ± 5°C.
  • Balance with accuracy up to 0.01 g.
  • Containers for sample drying (e.g., moisture cans).
  • Desiccators to cool samples post-drying.

Key specifications:

Moisture Content Formula:

[ \text{Moisture Content (%)} = \frac{W_1 - W_2}{W_2} \times 100 ]

Where:

• (W_1) = Weight of wet sample
• (W_2) = Weight of dry sample

Additional info:

• Use Appendix A of IS 4332 Part 3 for a recommended proforma to record results.
• Definitions and terms follow IS 2809 (1972).

flowchart LR
    A[Sample Collection] --> B[Weigh Wet Sample (W1)]
    B --> C[Dry in Oven at 110±5°C]
    C --> D[Cool in Desiccator]
    D --> E[Weigh Dry Sample (W2)]
    E --> F[Calculate Moisture Content %]

This ensures standardized moisture content determination for materials testing.

IS 4332 Part 3: Preparation of Soil Sample (Clause 5)

• Reference for Preparation: Follow IS 4332 Part 1 (1967) for detailed methods on sampling and preparation of stabilized soils.

• Sample Size: Prepare eight samples of 2 kg each from the obtained soil sample.

• Mixing Procedure: Mix water and stabilizer uniformly with the soil as per IS 4332 Part 1 guidelines.

Key Points from IS 4332 Part 1 (Relevant to Preparation):

Typical Mixing Formula:

[ \text{Water content} = \text{Optimum Moisture Content (OMC)} \pm 2% ]

[ \text{Stabilizer content} = \text{As per design, e.g., } 3% \text{ to } 10% \text{ by dry weight of soil} ]

flowchart TD
    A[Obtain Soil Sample] --> B[Air Dry / Oven Dry]
    B --> C[Pass through 4.75 mm Sieve]
    C --> D[Weigh 2 kg Samples]
    D --> E[Mix with Water and Stabilizer]
    E --> F[Compact in Molds for Testing]

Summary: Use 2 kg samples, mix uniformly with water and stabilizer per IS 4332 Part 1, and prepare 8 samples for testing.

IS 4332 Part 3: Compaction of Stabilized Soil Mixtures — Key Points

Compaction Procedure (Clause 6.3.1)

• Complete compaction within 20 minutes after mixing.
• Distribute blows uniformly over each layer.
• Keep the rammer sleeve clean for free fall.
• Remove lumps sticking to the rammer.
• Score each compacted layer before adding the next.
• Fill mold leaving about 5 mm excess to be struck off.
• Remove collar and level off the surface carefully.
• Weigh the mold with compacted soil to nearest 1 gram.

Density Calculations

1. Wet Density (Clause 7.1.1):

[ \text{Wet Density} (\rho_w) = \frac{\text{Weight of compacted soil + mold} - \text{Weight of mold}}{\text{Volume of mold}} ]

2. Dry Density (Clause 7.2.2):

[ \text{Dry Density} (\rho_d) = \frac{\rho_w}{1 + w} ]

Where:

• ( w ) = moisture content (decimal) of the stabilized soil mixture.

Summary Table

flowchart TD
    A[Mix Soil + Stabilizer] --> B[Compact in Layers]
    B --> C[Score Each Layer]
    C --> D[Fill Mold (leave 5mm excess)]
    D --> E[Remove Collar & Level Surface]
    E --> F[Weigh Mold + Soil]
    F --> G[Calculate Wet Density]
    G --> H[Measure Moisture Content]
    H --> I

IS 4332 Part 3 focuses on determining Moisture Content and Dry Density for stabilized soil mixtures.

Key Steps & Specifications:

• Prepare soil-stabilizer mixtures at varying moisture contents.
• Compact samples using a standard method (e.g., Proctor compaction).
• Measure wet density and determine moisture content by oven drying.
• Calculate dry density (ρ_d) using:

[ \rho_d = \frac{\rho}{1 + w} ]

where:

• (\rho) = wet density (kg/m³)

• (w) = moisture content (decimal)

• Plot dry density vs. moisture content to obtain the moisture-density curve.

• Identify the Maximum Dry Density (MDD) and corresponding Optimum Moisture Content (OMC) at the peak of the curve.

Typical Output Table Format:

Summary:

• Plot dry density vs. moisture content curve.
• Report MDD and OMC at the curve peak.
• Use oven drying for moisture content determination.
• Use standard compaction method consistent with IS codes.

graph LR
A[Prepare Soil-Stabilizer Mix] --> B[Compact Samples at Different Moisture Contents]
B --> C[Measure Wet Density]
C --> D[Determine Moisture Content (Oven Drying)]
D --> E[Calculate Dry Density]
E --> F[Plot Dry Density vs. Moisture Content]
F --> G[Identify MDD & OMC]

This procedure ensures optimal compaction parameters for stabilized soils per IS 4332 Part 3.

IS 4332 Part 3: Moisture Content - Dry Density Curve

Key Specifications:

• Plotting: Dry densities (ρ_d) of compacted soil-stabilizer mixtures are plotted against corresponding moisture contents (w%).
• Curve: A smooth curve is drawn through these points.
• Optimum Values: The maximum dry density (ρ_dmax) and the optimum moisture content (OMC) correspond to the peak of this curve.

Dry Density Calculation (Clauses 7.1.2 & 7.2.2):

[ \rho_d = \frac{\rho}{1 + w} ]

Where:

• (\rho_d) = Dry density (g/cm³ or Mg/m³)
• (\rho) = Bulk density (wet density) of compacted mixture
• (w) = Moisture content (decimal form, e.g., 0.12 for 12%)

Procedure Summary:

• Prepare samples at different moisture contents.
• Compact each sample to a standard effort.
• Measure bulk density and moisture content.
• Calculate dry density using the formula.
• Plot dry density vs. moisture content.
• Identify ρ_dmax and OMC from the curve.

Typical Moisture Content - Dry Density Curve

graph LR
A[Low Moisture Content] --> B[Increasing Dry Density]
B --> C[Peak: Maximum Dry Density (ρ_dmax) at Optimum Moisture Content (OMC)]
C --> D[Decreasing Dry Density with Excess Moisture]

This curve is critical for optimizing compaction and stabilizer content in soil stabilization projects.

IS 4332 Part 3: Calculation and Expression of Results

Key Formulas

• Wet Density (ρ_w):
  [ \rho_w = \frac{\text{Weight of mould + compacted mix} - \text{Weight of mould}}{\text{Volume of mould}} \quad (g/cm^3) ]

• Dry Density (ρ_d):
  [ \rho_d = \frac{\rho_w}{1 + \frac{w}{100}} \quad \text{where } w = \text{moisture content %} ]

• Air Voids Lines:
  Use the formula as per Clause 7.1.3 (not fully specified here, typically relates to void ratio and density).

Reporting

• Use the proforma in Appendix A for recording results.
• Round off values as per IS 2:1960 guidelines.
• Record parameters such as:
  • Weight of mould + compacted mixture (g)
  • Weight of mould (g)
  • Weight of compacted mixture (g)
  • Wet density (g/cm³)
  • Average moisture content (%)
  • Fluid stabilizer content (%)
  • Dry density (g/cm³)

Sample Table Format for Results

Note: Volume of mould is fixed and known for density calculations. Use consistent units throughout.

IS 4332 Part 3 — Reporting Key Points

Reporting Requirements (Clause 8)

• Record all test results clearly and systematically.
• Use the recommended proforma (Appendix A) for consistency.
• Include details such as weights, densities, moisture, and stabilizer content.

Key Data to Report (from Table 8)

Important Formulas

• Wet density, ρ_wet = (Weight of compacted mix) / (Volume of mould)
• Dry density, ρ_dry = ρ_wet / (1 + w)
  • where w = moisture content (decimal form)

Recommended Reporting Format (Summary)

• Test ID / Sample No.
• Weight of mould + mix (g)
• Weight of mould (g)
• Weight of compacted mix (g)
• Wet density (g/cm³)
• Moisture content (%)
• Stabilizer content (%)
• Dry density (g/cm³)

flowchart TD
    A[Weigh mould + compacted mix] --> B[Weigh empty mould]
    B --> C[Calculate weight of compacted mix]
    C --> D[Calculate wet density]
    D --> E[Measure moisture content]
    E --> F[Calculate dry density]
    F --> G[Record all data in report]

This ensures clear, standardized documentation for soil stabilizer compaction tests as per IS 4332 Part 3.