Methods of Tests for Building Limes, Part X: Determination of Popping and Pitting of Hydrated Lime
1973 Edition

Overview of Scope: Key Details and Requirements

• Defines methods for preparing and testing hydrated lime samples.
• Sample preparation aligned with IS 712:1973 Clause 7.2.
• Focus on physical inspection of lime pats for defects such as popping and pitting.
• Pats dried in ventilated ovens at temperatures ranging from 35 to 45°C for 4 to 16 hours.

Summary of Specifications and Procedures

Notes:

• Pats refer to shaped hydrated lime samples.
• Appropriate drying is essential for accurate physical test results.
• Visual criteria assist in identifying inferior lime quality.

Process Flowchart

flowchart TD
    A[Prepare sample as per IS 712:7.2] --> B[Form 4 test pats]
    B --> C[Allow setting for 30 minutes]
    C --> D[Transfer pats to base plates]
    D --> E[Dry in oven at 35-45°C for 4-16 hours]
    E --> F[Inspect pats for defects including disintegration, popping, and pitting]

For detailed formulas and tables, refer to IS 712 and the full IS 6932 documentation. This section mainly defines sample preparation and visual inspection scope.

Sample Preparation as per IS 6932 Part 10

Essential Steps and Parameters:

• Reference Standard: IS 712:1973 Clause 7.2 governs sample preparation.

• Mixing Specifications (Clause 3.2.1.1):

  • Combine 70 grams of hydrated lime with 70 milliliters of clean water maintained at 27 ± 3°C.
  • Allow the mixture to soak for 2 hours to ensure thorough hydration.

• Specimen Formation (Clauses 3.2.1.1 to 3.2.1.8):

  • Prepare four individual test specimens (pats) following the detailed steps.

• Setting and Drying (Clause 3.2.1.5):

  • Let the pats set undisturbed for 30 minutes.
  • Transfer them onto base plates and place in an oven maintained between 35 and 45°C.
  • Dry specimens for a duration ranging between 4 and 16 hours, with 16 hours preferred.

Summary Table:

flowchart TD
    A[Mix 70g hydrated lime + 70ml water at 27 ± 3°C] --> B[Let soak for 2 hours]
    B --> C[Form 4 test pats]
    C --> D[Allow setting for 30 minutes]
    D --> E[Dry in oven at 35-45°C]
    E --> F[Dry for 4 to 16 hours]

This method ensures consistent and standardized preparation of hydrated lime samples for testing.

Method for Detecting Popping and Pitting in Hydrated Lime (IS 6932 Part 10)

This section describes the procedure to identify popping (surface blisters) and pitting (surface depressions) which compromise lime durability.

Highlights:

• Objective: Detect and quantify surface defects such as popping and pitting in hydrated lime.
• Sample Preparation: Test specimens formed under controlled conditions.
• Testing Process: Specimens undergo drying and heating cycles to induce defects.
• Evaluation: Visual inspection and measurement of surface irregularities post-testing.
• Result Reporting: Defects are recorded and rounded off following IS 2-1960 guidelines.

Key Parameters:

Test Flow Diagram:

flowchart TD
    A[Prepare Lime Specimen] --> B[Drying Cycle]
    B --> C[Heating Cycle]
    C --> D[Inspect Surface]
    D --> E{Are popping/pitting defects present?}
    E -- Yes --> F[Measure and Document Defects]
    E -- No --> G[Specimen Passes Test]
    F --> H[Report Findings (Rounded per IS 2-1960)]

For detailed dimensions, test durations, and measurement procedures, consult the full IS 6932 Part 10 document.

Gauging Plaster Specifications According to IS 6932 Part 10

Essential Details:

• Plaster Type: Use fresh, fine, white Plaster of Paris (POP) free from popping and pitting when tested alone.
• Mixing Ratio: Blend POP with distilled water at 50% by mass.
• Initial Setting Time: Should be at least 15 minutes (tested with Vicat apparatus as per IS 4031-1968).

Mixing Method (Clause 3.2.1.2):

• After 2 hours of lime putty aging, mix thoroughly.
• Evenly sprinkle 10 grams of POP over the batch.
• Mix rapidly for 2 minutes to obtain a plastic consistency.

Application Technique (Clause 3.2.1.4):

• Apply gauged lime putty in small portions using a broad spatula.
• Avoid entrapping air bubbles.
• Smooth the surface with no more than 12 knife strokes.
• Complete smoothing within 5 minutes of mixing.

Summary Table for Gauging Plaster Preparation:

flowchart TD
    A[Prepare lime putty (2 hours)] --> B[Mix thoroughly]
    B --> C[Add 10g POP evenly]
    C --> D[Mix rapidly for 2 minutes]
    D --> E[Apply putty with spatula]
    E --> F[Smooth with ≤12 strokes]
    F --> G[Complete within 5 minutes]

This procedure ensures consistent gauging plaster quality essential for reliable testing.

Procedure for Preparing Test Specimens as per IS 6932 Part 10

Overview of Key Steps (Clauses 3.2.1.1 to 3.2.1.8):

• Produce four individual test specimens.
• Shape each specimen (pat) according to detailed instructions.
• Allow specimens to set for 30 minutes.
• Transfer specimens to base plates and place in a drying oven.
• Maintain oven temperature between 35°C and 45°C.
• Recommended drying duration is approximately 16 hours, though a minimum of 4 hours is acceptable.

Additional Requirements:

• Use distilled water for preparation as per updated standards.
• Follow sample preparation guidelines of IS 712-1973 Clause 7.2.
• Apply rounding rules for numeric values as per IS code.

Drying Conditions Summary:

flowchart TD
    A[Prepare 4 test specimens] --> B[Form pats as per specified clauses]
    B --> C[Allow setting for 30 minutes]
    C --> D[Transfer to base plates]
    D --> E[Place in drying oven at 35-45°C]
    E --> F{Drying time}
    F -->|Minimum 4 hours| G[Specimens ready for testing]
    F -->|Preferred 16 hours| G

This method guarantees uniform specimen preparation for consistent test outcomes.

Mixing and Shaping of Test Pats as per IS 6932 Part 10

• Dimensions of Pats:

  • Diameter: 10.0 cm
  • Thickness: 0.5 cm
  • Molding: Use ring molds greased inside with 1 gram petroleum jelly per pat (fresh applied each time).
  • Base: Non-porous plate, well greased.

• Procedure:

  • Press gauged lime mixture firmly into the ring mold placed on the greased plate to form flat pats.

• Drying:

  • Prepare four pats, allow them to set for 30 minutes.
  • Transfer with or without molds to drying oven at 35 to 45°C.
  • Dry for up to 16 hours, minimum 4 hours acceptable.
  • Pats may remain in oven before or between drying stages.

• Steaming:

  • Position four pats horizontally on base plates inside a boiling water steam boiler.
  • Expose to saturated steam at atmospheric pressure for 3 hours.
  • Take care to ensure condensed water does not drip onto the pat surfaces.

Summary Table:

flowchart TD
    A[Mix gauged lime material] --> B[Press into 10cm x 0.5cm ring molds]
    B --> C[Set for 30 minutes]
    C --> D[Dry in oven at 35-45°C for 16 hours]
    D --> E[Steam in saturated steam for 3 hours]

This ensures standardized preparation and conditioning of specimens for defect testing.

Inspection and Evaluation of Test Pats per IS 6932 Part 10

• Pats Specifications (Clause 3.2.1.3):

  • Diameter: 10.0 cm
  • Thickness: 0.5 cm
  • Mold preparation includes greasing interior with 1 gram petroleum jelly on a non-porous, greased plate.

• Pre-Steaming Inspection (Clause 3.2.1.7):

  • Reject any pats exhibiting shrinkage cracks before steaming.

• Steaming Process (Clause 3.2.1.8):

  • Place pats horizontally on base plates inside a boiling water steam boiler.
  • Subject to saturated steam at atmospheric pressure for 3 hours.
  • Ensure no droplets of condensed water fall on the pat surfaces.

• Post-Steaming Examination (Clause 3.2.2):

  • Inspect under adequate lighting for signs of disintegration, popping, or pitting.

Summary Table:

flowchart TD
    A[Prepare 10cm x 0.5cm pats] --> B[Grease mold and base plate]
    B --> C[Check for shrinkage cracks]
    C -- No cracks --> D[Steam for 3 hours at atmospheric pressure]
    D --> E[Inspect for defects]
    C -- Cracks present --> F[Reject and prepare new pats]

This ensures accurate assessment of lime quality and durability.

Assessment of Popping and Pitting Defects in Hydrated Lime (IS 6932 Part 10)

This section details the qualitative and quantitative evaluation of surface irregularities affecting lime quality.

Key Aspects:

• Purpose: Detect qualitative defects such as popping (surface blistering) and pitting (surface depressions) which impair lime performance.
• Application: Pertains to hydrated limes utilized in building construction.
• Test Principle: Expose lime samples to controlled conditions to provoke defect formation, followed by inspection.

Testing Outline:

1. Prepare lime paste or mortar specimens.
2. Cure specimens under specified temperature and humidity.
3. Observe and document any occurrence of popping or pitting.
4. Rate severity using qualitative or quantitative scales as per IS instructions.

Reporting:

• Test results are rounded according to IS 2-1960 standards.
• Clearly communicate the extent of observed popping and pitting.

Additional Notes:

• The method relies primarily on visual inspection; no explicit formulae are provided.

Process Flow Diagram:

flowchart TD
    A[Prepare Lime Sample] --> B[Cure under controlled conditions]
    B --> C{Inspect surface}
    C -->|No defects| D[Pass]
    C -->|Popping detected| E[Record severity]
    C -->|Pitting detected| F[Record severity]
    E & F --> G[Report results]

For comprehensive details, refer to the complete IS 6932 Part 10 standard.

Guidelines for Reporting Test Outcomes as per IS 6932 Part 10 (1973)

• Sample Preparation: Conducted in accordance with IS 712-1973 Clause 7.2.
• Drying Regime: Four test pats are set for 30 minutes, then dried at 35–45°C for 4 to 16 hours.
• Rounding Procedure: Test results must be rounded following IS 2-1960 rounding rules.
• Water Quality: Utilize distilled water conforming to updated specifications.
• Reporting Details:
  • Present observed or calculated values post rounding.
  • Include testing conditions such as drying temperature and duration.
  • Document sample preparation specifics.

Rounding Guidelines (IS 2-1960):

• Round numbers to the nearest digit based on the next decimal.
• Examples:
  • 2.345 rounded to 2 decimal places becomes 2.35
  • 2.344 rounded to 2 decimal places becomes 2.34

Sample Reporting Table:

flowchart TD
    A[Sample preparation per IS 712] --> B[Set for 30 minutes]
    B --> C[Dry at 35-45°C]
    C --> D[Dry for 4-16 hours]
    D --> E[Measure and calculate results]
    E --> F[Round results following IS 2-1960]
    F --> G[Compile and report findings]