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

IS 6932 Part 10 - Scope: Key Points & Specifications

Scope Summary:

• Covers preparation and testing of lime samples (building limes).
• Sample preparation per IS 712:1973 Clause 7.2.
• Focus on physical examination of pats for disintegration, popping, or pitting.
• Drying of pats in a ventilated oven at 35–45°C for 4 to 16 hours.

Key Specifications & Procedures

Notes:

• The pats are lime samples shaped for testing.
• Proper drying ensures reliable physical test results.
• Visual inspection criteria help identify poor quality lime.

Visual Summary (Process Flow)

flowchart TD
    A[Prepare Sample as per IS 712:7.2] --> B[Form 4 Pats]
    B --> C[Set for 30 minutes]
    C --> D[Transfer pats to base-plates]
    D --> E[Dry in oven at 35-45°C for 4-16 hrs]
    E --> F[Examine pats for defects (disintegration, popping, pitting)]

For detailed formulas or tables, refer to IS 712 and IS 6932 full text. This part primarily defines sample prep and visual test scope.

IS 6932 Part 10: Preparation of Sample for Lime Testing

Key Specifications & Steps:

• Sample Preparation Reference: As per IS 712:1973, Clause 7.2.

• Mixing (Clause 3.2.1.1):

  • Mix 70 g hydrated lime with 70 ml clean water at 27 ± 3℃.
  • Soak mixture for 2 hours.

• Specimen Formation (Clause 3.2.1):

  • Prepare 4 test specimens (pats) as per 3.2.1.1 to 3.2.1.8.

• Setting & Drying (Clause 3.2.1.5):

  • Leave pats to set for 30 minutes.
  • Transfer to drying oven at 35-45℃.
  • Dry for a total of 16 hours (minimum 4 hours may suffice).

Summary Table:

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

This ensures uniform sample preparation for consistent physical testing of hydrated lime as per IS standards.

IS 6932 Part 10 (1973): Test for Popping and Pitting of Hydrated Lime

This part specifies the method to determine popping and pitting defects in hydrated lime, which affect durability and quality.

Key Points:

• Objective: Identify and quantify popping (surface blistering) and pitting (surface depressions) in lime samples.
• Sample Preparation: Hydrated lime is formed into test specimens under controlled conditions.
• Test Procedure: Specimens are subjected to drying and heating cycles to provoke popping/pitting.
• Observation: Visual inspection and measurement of surface defects after test cycles.
• Reporting: Results are expressed as the extent of popping/pitting, rounded per IS 2-1960.

Typical Specification Highlights (from IS 6932 Part 10):

Summary Diagram of Test Process:

flowchart TD
    A[Prepare Lime Specimen] --> B[Drying Cycle]
    B --> C[Heating Cycle]
    C --> D[Inspect Surface]
    D --> E{Popping/Pitting Observed?}
    E -- Yes --> F[Measure Defects]
    E -- No --> G[Pass Test]
    F --> H[Report Results (Rounded per IS 2-1960)]

Note: For exact specimen dimensions, test cycle durations, and detailed measurement techniques, refer to the full IS 6932 Part 10 document. This ensures compliance with standardized testing and reporting.

Gauging Plaster Requirements (IS 6932 Part 10)

Key Specifications:

• Gauging plaster: Plaster of Paris (POP) mixed with 50% distilled water by mass.
• Initial setting time: ≥ 15 minutes (tested by Vicat needle per IS 4031-1968).
• Must be free from pops and pits when tested without lime.
• Use fresh, fine, white, good-quality POP.

Mixing Procedure (Clause 3.2.1.2):

• After 2 hours of lime putty aging, mix thoroughly.
• Add 10 g POP per batch, scatter evenly.
• Mix rapidly for 2 minutes to get a plastic mass.

Application (Clause 3.2.1.4):

• Press gauged putty in small quantities using a broad spatula.
• Avoid air bubbles.
• Smooth off with ≤ 12 strokes of the knife.
• Complete within 5 minutes from mixing to smoothing.

Summary Table: Gauging Plaster Mixing

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

This ensures consistent gauging plaster quality for reliable popping and pitting tests.

IS 6932 Part 10: Procedure for Preparation of Test Specimens

Key Steps (Clauses 3.2.1 to 3.2.1.8 Summary)

• Number of specimens: Prepare 4 separate test specimens.
• Forming pats: Each specimen is formed as per detailed steps (3.2.1.1 to 3.2.1.8).
• Setting time: Pats are left to set for 30 minutes.
• Drying: Transfer pats on base-plates (with/without ring mould) to a drying oven.
• Drying conditions: Oven temperature maintained between 35°C and 45°C.
• Drying duration: Total drying time about 16 hours is recommended; minimum 4 hours may suffice in some cases.

Additional Specifications:

• Water quality: Use distilled water (as per revised standards).
• Sample preparation: Follow IS 712-1973 Clause 7.2 for sample preparation.
• Rounding rules: Apply IS code rounding off rules for numerical values.

Summary Table: Drying Conditions for Test Specimens

flowchart TD
    A[Prepare 4 specimens] --> B[Form pats as per 3.2.1.1-3.2.1.8]
    B --> C[Set for 30 minutes]
    C --> D[Transfer to base-plates]
    D --> E[Place in drying oven (35-45°C)]
    E --> F{Drying time}
    F -->|Min 4 hours| G[Specimens ready for test]
    F -->|Prefer 16 hours| G

This procedure ensures consistent specimen preparation for reliable testing of hydrated lime properties.

Mixing and Forming Pats (IS 6932 Part 10)

• Pat Dimensions:

  • Diameter = 10.0 cm
  • Depth = 0.5 cm
  • Mold: Ring mould, greased inside with 1 g petroleum jelly per pat (renewed each time)
  • Base: Well-greased, non-porous plate

• Forming Procedure:

  • Press gauged material into the ring mould on the plate to form a flat pat (Clause 3.2.1.3).

• Drying:

  • Form 4 pats, leave to set for 30 minutes.
  • Transfer (with or without mould) to a drying oven at 35–45℃.
  • Dry for a total of 16 hours (minimum 4 hours may suffice).
  • Pats may remain in oven before or between drying periods (Clauses 3.2.1.5 & 3.2.1.6).

• Steaming:

  • Place 4 pats horizontally on base-plates in boiling water steam boiler.
  • Expose to saturated steam at atmospheric pressure for 3 hours.
  • Ensure no condensed water drips on pat faces (Clause 3.2.1.8).

Summary Table

flowchart TD
    A[Mix gauged material] --> B[Press into ring mould (10cm × 0.5cm)]
    B --> C[Set for 30 mins]
    C --> D[Dry in oven (35-45℃) for 16 hrs]
    D --> E[Steam in saturated steam for 

IS 6932 Part 10: Examination of Pats - Key Specifications & Procedure

• Pat Preparation (Clause 3.2.1.3):

  • Diameter: 10.0 cm
  • Depth: 0.5 cm
  • Mold: Ring mold, greased inside with petroleum jelly (1 g per pat) on a non-porous greased plate.

• Pre-Steam Inspection (Clause 3.2.1.7):

  • Reject any pats showing shrinkage cracks before steaming.

• Steaming (Clause 3.2.1.8):

  • Pats placed horizontally on base plates.
  • Subjected to saturated steam at atmospheric pressure for 3 hours in a boiling water steam boiler.
  • Ensure no condensed water drips on pat faces.

• Post-Steam Examination (Clause 3.2.2):

  • Inspect in good light for:
    • Disintegration
    • Popping
    • Pitting

Summary Table

flowchart TD
    A[Prepare Pat: 10cm × 0.5cm] --> B[Grease mold & plate with petroleum jelly]
    B --> C[Check for shrinkage cracks]
    C -- No cracks --> D[Steam in saturated steam at atmospheric pressure for 3 hrs]
    D --> E[Examine pats for disintegration, popping, pitting]
    C -- Cracks --> F[Reject & remake pats]

This procedure ensures the quality and durability of pats used in boiler testing as per IS 6932 Part 10.

IS 6932 Part 10 (1973): Test for Popping and Pitting of Hydrated Lime

This standard specifies the method to determine popping and pitting in hydrated lime, which affects the durability and performance of lime in construction.

Key Points:

• Purpose: To assess qualitative defects (popping and pitting) in hydrated lime that cause surface irregularities when lime sets.
• Scope: Applies to building limes used in construction.
• Test Principle: Hydrated lime is subjected to specific conditions to observe the formation of surface blisters (popping) or pits.

Test Procedure Summary:

1. Prepare a lime paste or mortar sample.
2. Cure under controlled conditions (temperature and humidity).
3. Observe and record any popping (blister formation) or pitting (surface depressions).
4. Rate the severity qualitatively or quantitatively as per IS guidelines.

Reporting:

• Results must be rounded off as per IS 2-1960.
• Report the extent of popping and pitting clearly.

Notes:

• No direct formula is provided in IS 6932 Part 10.
• The test is qualitative, relying on visual inspection and comparative rating.

Visual Summary (Mermaid Diagram):

flowchart TD
    A[Prepare Lime Sample] --> B[Cure under Controlled Conditions]
    B --> C{Observe Surface}
    C -->|No Defect| D[Pass]
    C -->|Popping Detected| E[Record Severity]
    C -->|Pitting Detected| F[Record Severity]
    E & F --> G[Report Results]

For detailed procedures, consult the full IS 6932 Part 10 text.

IS 6932 Part 10 (1973) - Reporting of Results: Key Points

• Sample Preparation: Follow IS 712-1973 Clause 7.2 for sample prep.
• Drying Conditions: Samples (4 pats) set for 0.5 hr, then dried at 35–45°C for 4–16 hours.
• Rounding Off: Final test values must be rounded as per IS 2-1960 rules.
• Water Quality: Use distilled water as per the revised specification.
• Result Reporting:
  • Report observed or calculated values after rounding.
  • Include test conditions (temperature, drying time).
  • Mention sample preparation details.

Rounding Off (IS 2-1960) - Summary:

• Round to the nearest number based on the digit following the last significant figure.
• Example:
  • 2.345 rounded to 2 decimals → 2.35
  • 2.344 rounded to 2 decimals → 2.34

Reporting Format Example:

flowchart TD
    A[Sample Prep per IS 712] --> B[Set for 0.5 hr]
    B --> C[Dry at 35-45°C]
    C --> D[Dry for 4-16 hrs]
    D --> E[Measure & Calculate]
    E --> F[Round values per IS 2-1960]
    F --> G[Report Results]