Method of test for determination of true specific gravity of natural building stones

IS 1122 - Scope Summary

IS 1122 primarily covers methods for testing natural building stones for various properties.

Key Points on Scope:

• Applicable to natural stones used in construction.
• Specifies sampling, testing, and reporting procedures.
• Reporting must include:
  • Identification of the sample
  • Date of sampling
  • Type of stone (Clause 6.3)

Important Reporting Guideline:

• Final test values must be rounded off as per IS 2:1960 (Rules for rounding off numerical values).

Contact & Reference:

• For detailed procedures and tables, refer to the full IS 1122 document.
• BIS regional offices handle queries and sales.

Typical Test Parameters Covered in IS 1122 (general knowledge):

flowchart TD
    A[Sample Collection] --> B[Identification & Documentation]
    B --> C[Testing as per IS 1122]
    C --> D[Result Evaluation]
    D --> E[Reporting (Include sample ID, date, stone type)]

For exact formulas and tables, please consult the full IS 1122 standard text.

IS 1122 - Sampling of Stone: Key Points & Specifications

• Clause 2.1:
  Sample must represent the true average quality of the stone grade under consideration.

• Clause 2.2:
  Sampling can be:

  • From quarried stone (2.2.1)
  • From natural rock (2.2.2)
    Sample size must be adequate to prepare the required number of test specimens.

• Clause 2.3:
  If variations in rock quality are noticeable, select multiple samples to capture the range of properties.

• Rounding Off Results (Clause 0.3):
  Follow IS 2:1960 for rounding test values.

Practical Sampling Guidelines (from IS 1122 + Engineering Practice)

flowchart TD
    A[Select Stone Type] --> B{Is Rock Quality Uniform?}
    B -- Yes --> C[Take 3 Samples]
    B -- No --> D[Take Multiple Samples to Cover Variations]
    C --> E[Prepare Test Specimens]
    D --> E
    E --> F[Perform Tests & Report Results]

Summary: Sampling must be representative, adequate in size, and account for variability to ensure reliable test results as per IS 1122.

IS 1122: Preparation of Test Sample - Key Points

• Sample Selection (Clause 2.2):
  Select from quarried stone or natural rock, ensuring sufficient quantity for all test pieces.

• Initial Sample (Clause 3.1):

  • Take 0.5 kg of stone.
  • Wash thoroughly to remove dust/coatings.
  • Dry and crush between hardened steel surfaces to max 3 mm particle size.
  • Mix thoroughly and reduce to 50 g test sample.

• Grinding (Clause 3.2):

  • Grind entire 50 g sample in an agate mortar until it passes a 150-micron IS sieve.
  • Remove any magnetic material introduced during crushing/grinding with a magnet.

• Rounding Off Results (Clause 0.3):
  Follow IS 2-1960 for rounding off final test values.

Summary Table

flowchart TD
    A[Select stone sample (0.5 kg)] --> B[Wash and dry]
    B --> C[Crush to ≤ 3 mm particles]
    C --> D[Mix and reduce to 50 g]
    D --> E[Grind in agate mortar]
    E --> F[Pass 150-micron sieve]
    F --> G[Remove magnetic particles]
    G --> H[Ready for testing]

This ensures a representative, clean, and fine test sample as per IS 1122 requirements.

IS 1122: Apparatus - Key Formulas & Specifications

True Specific Gravity Calculation (Clause 6.1)

[ \text{True specific gravity at } t^\circ C = \frac{(W_3 - W_2)}{(W_4 - W_1)} ]

Where:

• ( W_1 ) = Weight of empty specific gravity bottle with stopper (g)
• ( W_2 ) = Weight of bottle + stopper + powder (g)
• ( W_3 ) = Weight of bottle + stopper + powder + distilled water (to fill bottle) (g)
• ( W_4 ) = Weight of bottle + stopper + distilled water (g)
• ( t ) = Room temperature (°C)

Apparatus Specifications (Clause 4.5)

• Weighing Bottle: Must be of standard size and calibrated for specific gravity measurement.
• Desiccator: Used to keep samples moisture-free before weighing.

Additional Notes

• Final values should be rounded per IS : 2-1960 guidelines.
• Use distilled water at room temperature for accurate measurements.

flowchart LR
    A[Empty Bottle + Stopper (W1)] --> B[Add Powder (W2)]
    B --> C[Add Distilled Water to Fill (W3)]
    A --> D[Add Distilled Water Only (W4)]
    C & D --> E[Calculate True Specific Gravity]

This formula and apparatus ensure precise determination of powder density by displacement method as per IS 1122.

IS 1122: Procedure for Determining True Specific Gravity of Stone Powder

Key Steps (Clause 5.2.1)

• Dry stone powder (~15 g) placed in specific gravity bottle; weigh → W2.
• Add distilled water (~3/4 volume), boil gently for 10 min to remove air, cool to room temp.
• Fill bottle fully with distilled water, stopper, clean outside, weigh → W3.
• Empty, clean bottle; fill fully with distilled water, stopper, weigh → W4.
• Record room temperature → t°C.

Formula (Clause 6.1)

[ \text{True Specific Gravity at } t^\circ C = \frac{(W_2 - W_1) - (W_3 - W_4)}{W_4 - W_1} ]

Where:

Reporting

• Round off final values as per IS 2-1960.
• Report true specific gravity at recorded room temperature.

flowchart TD
    A[Empty Bottle + Stopper] -->|Weigh| W1
    B[Add Stone Powder (~15g)] -->|Weigh| W2
    B --> C[Add 3/4 distilled water]
    C --> D[Boil 10 min to remove air]
    D --> E[Cool to room temp]
    E --> F[Fill fully with distilled water]
    F -->|Weigh| W3
    G[Empty & Clean Bottle] --> H[Fill fully with distilled water]
    H -->|Weigh| W4
    W1 & W2 & W3 & W4 --> I[Calculate Specific Gravity]

This procedure ensures accurate measurement of stone powder's true specific gravity per IS 1122.

IS 1122: Calculation and Expression of Results

Key Formula for True Specific Gravity (Clause 6.1)

[ \text{True specific gravity at } t^\circ C = \frac{(W_1 - W_2) - (W_3 - W_2)}{W_2 - W_1} ]

Where:

• ( t ) = room temperature (°C)
• ( W_1 ) = weight of empty specific gravity bottle with stopper (g)
• ( W_2 ) = weight of bottle + stopper + powder (g)
• ( W_3 ) = weight of bottle + stopper + powder + distilled water to fill bottle (g)
• ( W_4' ) = weight of bottle + stopper + distilled water (g)

Rounding Off (Clause 0.3)

• Round off final values as per IS 2:1960 rules on numerical rounding.

Additional Notes:

• Use an analytical balance for precise weighing (Clause 4.1).
• Ensure all weights are measured at room temperature for accuracy.

Summary Table for Weights

flowchart LR
    A[Empty Bottle + Stopper (W1)] --> B[Add Powder (W2)]
    B --> C[Add Distilled Water to Fill (W3)]
    A --> D[Add Distilled Water (W4')]
    C --> E[Calculate True Specific Gravity]

Use this formula and procedure to accurately determine specific gravity and report results as per IS 1122.

Precision and Accuracy in IS 1122

IS 1122 emphasizes accurate measurement using analytical balances and proper calculation methods.

Key Formula for True Specific Gravity (Clause 6.1):

[ \text{True Specific Gravity at } t^\circ C = \frac{(W_2 - W_1)}{(W_2 - W_1) - (W_3 - W_4')} ]

Where:

• ( W_1 ) = Weight of empty specific gravity bottle with stopper (g)
• ( W_2 ) = Weight of bottle + stopper + powder (g)
• ( W_3 ) = Weight of bottle + stopper + powder + distilled water (g)
• ( W_4' ) = Weight of bottle + stopper + distilled water (g)
• ( t ) = Room temperature (°C)

Rounding Off (Clause 0.3):

• Follow IS 2-1960 for rounding results.
• Round off only the final reported value.
• Use standard rounding rules (e.g., ≥5 rounds up).

Analytical Balance & Weights (Clause 4.1):

• Use a balance with precision suitable for the weight range.
• Calibrate regularly with standard weights.

Summary Table: Specific Gravity Calculation

flowchart TD
    A[Empty Bottle + Stopper (W1)]
    B[Bottle + Stopper + Powder (W2)]
    C[Bottle + Stopper + Powder + Water (W3)]
    D[Bottle + Stopper + Water (W4')]
    E[Calculate True Specific Gravity]
    
    A --> E
    B --> E
    C --> E
    D --> E

This ensures precision (repeatable measurements) and accuracy (correctness) in specific gravity determination.

Reporting as per IS 1122

Key Points:

• Rounding Off:
  Final observed or calculated values must be rounded according to IS 2:1960 (Rules for rounding off numerical values).

• Information to Report (Clause 6.3):
  Reports must include:

  • Identification of the sample
  • Date the sample was taken
  • Type of stone tested

Summary Table for Reporting Requirements

Rounding Off Rules (IS 2:1960 Summary)

• If the digit to be dropped is <5, round down.
• If the digit is >5, round up.
• If the digit is exactly 5, round to the nearest even digit.

flowchart TD
    A[Start: Test/Analysis] --> B{Final Value Obtained?}
    B -->|Yes| C[Round off as per IS 2:1960]
    C --> D[Report Sample ID, Date, Stone Type]
    D --> E[Submit Report]

For detailed rounding rules, refer to IS 2:1960. Reporting clarity ensures traceability and compliance.