Method for determination of slake durability index of rocks

IS 10050: Scope - Key Formulas, Tables, and Specifications

Scope Summary:

IS 10050 covers the slake-durability test for rock classification based on durability indices.

Key Formula:

• Second cycle slake-durability index (Id₂) is calculated using test procedure at 20℃ with tap water.
• For samples with Id₂ between 0-10%, use the first cycle slake-durability index (Id₁) for further classification.

Slake-Durability Classification (Table 1):

Units & Symbols (SI Units):

Notes:

• Final reported values should be rounded as per IS 2-1960.
• The durability index helps in rock classification for engineering applications.

flowchart TD
    A[Rock Sample] --> B[Slake Durability Test]
    B --> C{Second Cycle Id (Id₂)}
    C -->|0-10%| D[Check First Cycle Id (Id₁)]
    C -->|>10%| E[Classify Rock]
    D --> E
    E --> F[Classification Table]

This provides a concise overview of the scope, key formula, classification table, and units from IS 10050.

IS 10050 Key References: Slake-Durability Index & Units

1. Slake-Durability Index (SDI) Classification (Clause 6.2, Table 1)

2. Second Cycle Slake-Durability Index (Clause 6.3)

• Use tap water at 20℃ for testing.
• For samples with second cycle SDI between 0 to 10%, further characterization by first cycle SDI is required.

3. International System of Units (SI Units)

4. Reporting

• Round off results as per IS 2-1960.

flowchart LR
    A[Sample Preparation] --> B[First Cycle Test]
    B --> C{SDI (1st cycle) Result}
    C -->|0-10%| D[Second Cycle Test]
    C -->|>10%| E[Classification using Table 1]
    D --> F[Second Cycle SDI Result]
    F --> G{Classify Rock}

This summary aids in rock durability classification and consistent reporting using IS 10050 standards.

IS 10050 - Apparatus for Slake Durability Test

Key Specifications (Clause 3)

• Slaking Fluid: Tap water at 20℃ (Clause 2.1)
• Apparatus Components:
  • A rotating drum with perforations to hold rock fragments
  • Drum rotation mechanism
  • Water container maintaining slaking fluid temperature
  • Sieves for separating fragments after testing
• Figure Reference: Fig. 1 (Line diagram of apparatus) shows the setup.

Important Units & Definitions (SI Units)

Key Formula for Slake Durability Index (SDI)

[ \text{SDI} = \frac{\text{Weight of fragments retained after cycle}}{\text{Initial weight of fragments}} \times 100 ]

• Second cycle SDI is used for classification (Clause 6.3).
• For second cycle SDI between 0-10%, first cycle SDI must be reported.

Summary Diagram of Apparatus Setup

flowchart LR
    A[Rock Fragments] --> B[Rotating Drum with perforations]
    B --> C[Slaking Fluid (Tap water @ 20℃)]
    B --> D[Rotation Mechanism]
    B --> E[Sieves for fragment separation]
    E --> F[Measurement of retained fragments]

Note: Numerical results must be rounded as per IS 2-1960.

IS 10050: Test Procedure Key Points

1. Equipment

• Use a balance accurate to 0.5 g for weighing drum + sample (Clause 3.5).

2. Slake-Durability Index Calculation

• The second cycle slake-durability index (Id₂) is used for rock classification.
• For samples with Id₂ between 0-10%, evaluate the first cycle slake-durability index (Id₁) for further characterization.

3. Slake-Durability Index Classification (Table 1, Clause 6.2)

4. Reporting Results (Clause 6.3)

• Round off values per IS 2-1960.
• Use tap water at 20°C for tests.
• Slake-durability indices are expressed as percentages.

Formula for Slake-Durability Index (Id)

[ Id = \frac{\text{Mass after test}}{\text{Original mass}} \times 100 ]

flowchart LR
    A[Weigh Original Sample] --> B[Test in Drum with Water]
    B --> C[Dry and Weigh Sample]
    C --> D[Calculate Id = (Mass after / Original Mass) * 100]
    D --> E{Id Range?}
    E -->|0-25| F[Very Low]
    E -->|26-50| G[Low]
    E -->|51-75| H[Medium]
    E -->|76-90| I[High]
    E -->|91-95| J[Very High]
    E -->|96-100| K[Extremely High]

Summary: Use precise weighing, calculate slake-durability indices over two cycles, classify rock durability per Table 1, and report results following IS rounding rules.

IS 10050: Key Formulas, Tables & Specifications for Slake Durability Calculation

1. Slake Durability Index (Second Cycle) Calculation

• Use tap water at 20℃ for the test.
• The second cycle slake durability index (Id₂) is calculated as per Clause 5 (not fully provided here).
• For samples with Id₂ from 0 to 10%, further characterization is done by the first cycle slake durability index (Id₁).

2. Classification Table (Clause 6.2, Table 1)

3. Units & Symbols (SI Units) for Reporting

4. Rounding Off Results

• Follow IS : 2-1960 for rounding off final values.

flowchart TD
    A[Start: Sample Preparation] --> B[First Cycle Test]
    B --> C[Calculate Id₁]
    C --> D{Id₂ (Second Cycle) Test}
    D --> E[Calculate Id₂]
    E --> F{Is Id₂ between 0-10%?}
    F -->|Yes| G[Use Id₁ for further classification]
    F -->|No| H[Use Id₂ for classification]
    G --> I[Refer to Table 1 for classification]
    H --> I
    I --> J[Report results with

IS 10050 - Reporting of Results: Key Formulas & Tables

1. Slake-Durability Index (Second Cycle) Formula (Clause 5.1)

[ \text{Id}_2 = \frac{A - D}{C - D} \times 100 % ]

• A = Weight of the sample after second cycle drying (g)
• C = Weight of the sample before test (g)
• D = Weight of non-rock material (e.g., fines) (g)

2. Classification Based on Slake-Durability Index (Clause 6.2, Table 1)

3. Notes on Reporting (Clause 6.3)

• Use second cycle slake-durability index at 20℃ tap water for classification.
• For samples with second cycle index 0-10%, further analyze first cycle slake-durability index.
• Round off results as per IS 2:1960.

4. SI Units Used (Summary)

flowchart TD
    A[Initial Dry Weight (C)] --> B[Slake Durability Test]
    B --> C[Second Cycle Dry Weight (A)]
    B --> D[Non-rock Material Weight (D)]
    C & D --> E[Calculate Id2 = ((A-D)/(C-D))*100]
    E --> F[Classify Rock Durability]

This concise framework ensures standardized reporting of slake-durability test results per IS 10050.

IS 10050: Slake Durability Index (SDI) - Key Formula & Classification

Key Formula (Clause 5.1)

The Slake Durability Index (Second Cycle), Id2 is calculated as:

[ \text{Id}_2 = \frac{A - D}{C - D} \times 100% ]

Where:

• A = Weight of dry sample after second cycle (g)
• C = Weight of dry sample before test (g)
• D = Weight of insoluble residue (g)

Classification of Slake Durability Index (Typical Ranges)

Notes:

• The test involves cyclic wetting and drying to simulate natural weathering.
• The second cycle index (Id2) is considered more reliable for classification.
• Results help in assessing rock suitability for construction and engineering purposes.

flowchart LR
    Start[Test Sample Preparation] --> Wetting[Wet Sample Cycle 1]
    Wetting --> Drying[Dry Sample Cycle 1]
    Drying --> Weigh1[Weigh Sample (A1)]
    Weigh1 --> Wetting2[Wet Sample Cycle 2]
    Wetting2 --> Drying2[Dry Sample Cycle 2]
    Drying2 --> Weigh2[Weigh Sample (A)]
    Weigh2 --> Calculate[Calculate Slake Durability Index]

This concise summary provides the essential formula and classification for SDI per IS 10050.