Methods of test for stabilized soils, Part 8: Determination of lime content of lime stabilized soils
1969 Edition

Overview of Scope and Key Tables

Grain Size Classification (Clause 2.1)

Sample Divider Specifications (Clause 3.8)

Lime Content Determination (Appendix A, Clause 7.2.1)

• Oven-dry sample weight (W, grams)
• EDTA titration volume (V, ml)
• Lime percentage calculated using:

[ \text{Lime Content (%)} = 100 \times \frac{Y \times X}{W} ]

where X and Y values vary according to soil type.

• Detailed recording format provided in Appendix A.

Summary Points

• Select riffle box openings based on soil grain size.
• Soil grading determined by sieve analysis.
• Lime content calculated by combining titration data and oven-dried sample weight.

Refer to Appendix A for full procedural details.

flowchart TD
    A[Collect Soil Sample] --> B{Identify Grain Size}
    B -->|Fine| C[Use 6 mm Riffle Box]
    B -->|Medium| D[Use 6 mm & 2.5 cm Openings]
    B -->|Coarse| E[Use 6 mm & 5 cm Openings]
    A --> F[Dry Sample and Weigh (W)]
    F --> G[Perform EDTA Titration (V)]
    G --> H[Compute Lime Content]

Note: Always consult the latest edition of the standard for updates.

Key Definitions and Soil Classification (Clause 2.1 & 3.8)

Soil Gradation Categories

Sample Divider Slot Widths

Lime Content Calculation Parameters (Appendix A)

• Oven-dried sample weight (W, g)
• EDTA titration volume (V, ml)
• Lime content expressed as:

[ TC = 100 \times \frac{Y}{X} ]

Where values X and Y depend on titration volume and sample weight.

• Lime percentage relative to dry soil:

[ C = \frac{(C_1 - C_2)}{C_3} \times 100 ]

Refer to Appendix A for variable definitions.

Soil Classification and Sample Divider Selection

flowchart TD
    A[Soil Sample] --> B{Determine Grain Size}
    B -->|Fine (<2mm)| C[Use 6mm Riffle Box]
    B -->|Medium (2-20mm)| D[Use 6mm and 2.5cm Divider]
    B -->|Coarse (20-40mm)| E[Use 6mm and 5cm Divider]

Please follow IS 4332 Part 8 for comprehensive test methods and recording templates.

Essential Apparatus and Specifications (Clause 3.8 & 3.19)

Sample Dividers

• Multiple-slot riffle boxes with slot widths based on soil grain size:

Heating Devices

• Use an electric hotplate or Bunsen burner for sample digestion.

Analytical Reagents

• Analytical grade chemicals required.

Lime Content Calculation

• Record sample weights and titration volumes accurately.

Key formula:

[ \text{Lime Content (%)} = 100 \times \frac{Y \times X}{W} ]

Where:

• Y = EDTA volume for soil-lime sample
• X = EDTA volume for soil
• W = Oven-dried sample weight (g)

Apparatus Summary

flowchart LR
    A[Soil Sample] --> B[Sample Divider]
    B --> C[Weighing Container]
    C --> D[Heating Device]
    D --> E[EDTA Titration]
    E --> F[Calculate Lime Content]

This section highlights required equipment for executing the lime content test as per IS 4332 Part 8.

Reagents and Calculation Essentials (Clauses 4.1, 3.19 & 7.1.1)

Reagent Preparation

• EDTA Solution: Dissolve 4 g of disodium EDTA in 1 litre of distilled water.
• Use only analytical grade chemicals.
• Neutralize extracted solution with dilute ammonia until red litmus turns blue.

Critical Formulas

Notes

• Variables X, Y, Z represent EDTA volumes for soil, soil-lime, and lime samples respectively.
• Accurate measurement of sample weights and titration volumes is essential.
• Endpoint indicated by color change using suitable buffer and indicator.

flowchart LR
    A[Prepare Soil Extract] --> B[Neutralize with Ammonia]
    B --> C[Titrate with EDTA]
    C --> D[Record Volume V]
    D --> E[Compute Lime Content]

This section summarizes reagent preparation and calculation fundamentals.

Guidelines for Preparing Soil-Lime and Natural Soil Samples (Clause 5.2 & 7.1.1)

Sample Sizes by Soil Type

• Samples are reduced by successive riffling using an appropriate sample divider.

EDTA Titration Volume Calculations

• For fine-grained soils or soil-lime:

  [ X \text{ or } Y = \frac{w \times 25}{V} ]

• For medium or coarse-grained soils or soil-lime:

  [ X \text{ or } Y = \frac{100 \times V}{w} \quad (ml) ]

Where:

• V = volume of EDTA titrated (ml)
• w = oven-dried sample weight (g)

Lime Content Computation

• Uncarbonated soil-lime lime content percentage (C1):

  [ C_1 = 100 \times \frac{(Y - X)}{Z - X} ]

• Lime content as percentage of dry soil weight (C2):

  [ C_2 = \frac{100 \times C_1}{100 + C_1} ]

Where:

• X = EDTA volume for soil
• Y = EDTA volume for soil-lime
• Z = EDTA volume for lime

Following these steps ensures representative sampling and precise lime content determination.

Step-by-step Analytical Methodology (Clauses 5.3, 6.2 & 7.1.1)

Sample Processing

• Dry sample in oven at 105–110°C for 16–24 hours until weight change is less than 0.1%.
• Pulverize sample to pass a 425-micron IS sieve.
• Subdivide using riffle box with 6 mm openings.
• Sample weights for titration:
  • Fine-grained: ~5 g
  • Medium-grained: ~25 g
  • Coarse-grained: ~50 g

Titration Procedure

• Add red litmus paper to flask containing acid or ammonium chloride extract.
• Neutralize with dilute ammonia until litmus turns blue (if acid extract).
• Dilute extract to 250 ml with distilled water.
• After settling, pipette 50 ml clear supernatant.
• Add 2 ml buffer and 3–4 drops of indicator.
• Titrate with EDTA until color change observed.

Calculation Formulas

Notes

• Variables X, Y, Z are volumes of EDTA for soil, soil-lime, and lime samples respectively.
• Measurements must be precise for reliable results.

Calculation Procedures for Lime Content from Titration Data (Clause 7.1.1)

EDTA Volume per Gram of Sample

• Fine-grained soil or soil-lime:

[ X \text{ or } Y = \frac{25V}{W} ]

• Medium or coarse-grained soil or soil-lime:

[ X \text{ or } Y = \frac{100V}{W} ]

• Lime sample:

[ Z = \frac{50V}{W} ]

Where:

• V = volume of EDTA titrant (ml)
• W = oven-dried sample weight (g)
• X = EDTA volume for soil
• Y = EDTA volume for soil-lime
• Z = EDTA volume for lime

Calculating Lime Content

• Lime percentage in uncarbonated soil-lime (by soil-lime weight):

[ C_1 = 100 \times \frac{Y - X}{Z - X} ]

• Lime content as percentage of dry soil mass:

[ C_2 = \frac{100 \times C_1}{100 + C_1} ]

Sample Divider Slot Widths (Clause 3.8)

Recording Recommendations (Appendix A)

• Document sample info, weights, titration readings, calculated X, Y, Z values, and lime content C1 and C2.

flowchart TD
    A[Dry Sample (W)] --> B[EDTA Titration (V)]
    B --> C{Soil Type}
    C -->|Fine| D[Calculate X or Y = (25V)/W]
    C -->|Medium/Coarse| E[Calculate X or Y = (100V)/W]
    D & E --> F[Calculate Lime Content C1 and C2]

This section explains formulas and procedures for calculating lime from titration results.

Guidelines for Reporting Lime Content Results (Clause 7.2 & Appendix A)

Reporting Accuracy

• Lime content values (C1 or C2) should be reported rounded to the nearest 0.2%.

Important Formulas

Sample Divider Opening Widths

Recommended Documentation

• Include sample identification, operator, date, description, weights, titration readings, EDTA volumes, and calculated lime content.
• Use the proforma in Appendix A for uniform reporting.

flowchart TD
    A[Weigh Oven-Dried Sample] --> B[Perform EDTA Titration]
    B --> C[Calculate X or Y]
    C --> D[Compute Lime Content C1 and C2]
    D --> E[Round Results to Nearest 0.2%]
    E --> F[Prepare Report]

This section provides best practices for reporting lime content test outcomes.

Standardized Proforma for Documenting Lime Content (Appendix A, Clause 7.1.1 & 7.2)

Calculation Formulas

• Fine-grained soils:

  [ X \text{ or } Y = \frac{w \times 25}{V} \quad (ml) ]

• Medium/coarse-grained soils:

  [ X \text{ or } Y = \frac{100 \times V}{w} \quad (ml) ]

• Lime sample:

  [ Z = \frac{V}{W} \quad (ml) ]

• Lime content for uncarbonated soil-lime (C1):

  [ C_1 = 100 \times \frac{Y - X}{Z - X} ]

• Lime content as percent of dry soil weight (C2):

  [ C_2 = \frac{100 \times C_1}{100 + C_1} ]

Suggested Recording Table

Reporting Precision

• Report lime content rounded to the nearest 0.2%.

Sample Calculation Workflow

flowchart TD
    A[Weigh Oven-Dried Sample (W)] --> B[Conduct EDTA Titration]
    B --> C[Calculate X, Y, and Z]
    C --> D[Determine Lime Content C1 and C2]
    D --> E[Record Results in Proforma]

This appendix provides a standardized template to assist in consistent documentation of lime content test results.