Cinder as Fine Aggregates for use in Lime Concrete

IS 2686: Scope - Key Points & Specifications

Scope (Clause 2.0):
Defines the applicability of the standard for testing and specifying the properties of certain materials (e.g., aggregates for concrete).

Sampling (Clause 2.4 & 7.1)

• Sample Preparation:

  • Final sample must pass through a 150-micron IS sieve after grinding.
  • Drying over a steam bath if necessary.
  • Machine grinding should avoid excessive fineness to prevent altering test results.

• Sampling Details:

  • Refer to Appendix C for detailed sampling procedures.

Sulphate Content Determination (Appendix A, Clause 6.1)

• Sample preparation and testing methods for sulphate content are specified to ensure durability and chemical resistance.

Summary Table: Sampling Procedure

For detailed test methods and formulas, refer to Appendix A (sulphate content) and Appendix C (sampling).

flowchart TD
    A[Sample Collection] --> B[Grinding to pass 150-micron sieve]
    B --> C{Is drying needed?}
    C -- Yes --> D[Dry over steam bath]
    C -- No --> E[Proceed to testing]
    D --> E

Note: IS 2686 focuses on material sampling and testing to ensure quality compliance in construction materials.

IS 2686 - Definitions & Sampling Key Points

• Clause 2.0: Defines terms used in the standard for clarity and uniformity.

• Clause 2.4 (Sampling):

  • Final sample must pass a 150-micron IS sieve completely.
  • Drying (if needed) done over a steam bath to avoid altering sample properties.
  • Machine grinding allowed but must not excessively reduce particle size beyond 150 microns.
  • The prepared sample is then used for testing.

Important Specifications for Sampling

Summary Diagram: Sampling Process

flowchart TD
    A[Collected Sample] --> B[Dry if needed over Steam Bath]
    B --> C[Grind sample carefully]
    C --> D[Pass through 150-micron IS Sieve]
    D --> E[Final Sample for Testing]

This ensures representative and consistent test results as per IS 2686.

Classification of Cinder Aggregates (IS 2686: 1977)

1. Classes of Cinder Aggregate (Clause 4.1)

• Class A: For general purposes.
• Class B: For interior work not exposed to damp conditions.
• Class C: For precast blocks.

2. Grading Requirements (Clause 5.1)

• These are average grading values; further crushing may be done to suit specific needs.

3. Notes

• Soundness test is not required as per the revised standard.
• Rounding off test results should follow IS 2-1960 rules.

This classification ensures suitability of cinder aggregates for various construction uses based on exposure and structural requirements.

IS 2686 Sampling Key Points & Specifications

Sampling Procedure (Clause 7.1 & Appendix C)

• Objective: Obtain a sample representing the coarse and fine proportions accurately (C-1.1).
• Initial Sample Size (C-1.3):
  • 5–10 tonnes consignment: 15–20 kg
  • 50+ tonnes consignment: 45–90 kg
  • Intermediate: Proportionate size.

Sample Preparation (Table C-2.4)

• Final sample ground to pass 150-micron IS sieve completely.
• Dry sample over a steam bath if needed.
• Machine grinding allowed but avoid excessive fineness.
• The prepared sample is then used for testing.

Summary Table: Sample Size vs Consignment

flowchart TD
    A[Consignment] --> B[Initial Sample]
    B --> C[Grinding to pass 150-micron sieve]
    C --> D[Drying (steam bath if needed)]
    D --> E[Final Sample for Testing]

Note: Sampling must ensure representative material to detect deleterious constituents mainly found in fines.

IS 2686 - Grading of Cinder Aggregate (Clause 5.1)

The average grading for cinder aggregate is specified as:

Key Points:

• Grading controls particle size distribution to ensure proper workability and strength.
• Users may further crush aggregates to suit specific requirements.
• The standard provides average grading; actual grading may vary.
• Final test values should be rounded as per IS 2-1960.

Classes of Cinder Aggregate (Clause 4.1):

• Class A: General purposes
• Class B: Interior work, not exposed to dampness
• Class C: Precast blocks

Summary Diagram of Grading Curve:

graph LR
    A[10 mm] -->|100% passing| B[4.75 mm]
    B -->|80% passing| C[2.36 mm]
    C -->|60% passing| D[1.18 mm]
    D -->|40% passing| E[600 micron]
    E -->|30% passing| F[300 micron]
    F -->|25% passing| G[150 micron]
    G -->|16% passing| H[Fine particles]

This grading ensures a well-graded aggregate suitable for structural concrete with cinder as aggregate.

IS 2686: Characteristics of Cinder Aggregate

1. Grading (Clause 5.1, Table 5)

2. Sampling & Preparation (Clause 2.4)

• Final sample ground until fully passes 150-micron sieve.
• Dry using steam bath if necessary.
• Avoid excessive fineness during machine grinding.
• The prepared sample is used for testing.

3. Key Specifications

• Aggregate must conform to above grading for suitability in concrete.
• Proper sampling and preparation ensure test accuracy.

This ensures uniformity and quality control for cinder aggregate in construction per IS 2686.

IS 2686 — Testing Methods: Key Points

Sample Preparation (Clause 2.4)

• Final sample ground to pass 150-micron IS sieve.
• Drying over steam-bath if needed.
• Machine grinding should avoid excessive fineness.
• Sample subjected to tests after preparation.

Sulphate Content Determination (Appendix A, Clause 6.1)

• Wash sample with distilled water until chloride-free.
• Filter and fold wet filter paper into ignited silica capsule.
• Ignite at 800°C for 15 minutes on silica plate.
• Cool in desiccator and weigh.
• Dry precipitate at 105 ± 5°C to constant mass after filtration.

Criteria for Conformity (Clause 7.2)

• If initial test fails, repeat on two more portions.
• If both pass, consignment accepted.
• If either fails, consignment rejected.

Summary Table: Sample Preparation & Testing

flowchart TD
    A[Sample Collection] --> B[Grinding (150-micron sieve)]
    B --> C[Drying (Steam bath if needed)]
    C --> D[Testing]
    D --> E{Pass?}
    E -- Yes --> F[Consignment Accepted]
    E -- No --> G[Repeat Test on 2 Samples]
    G --> H{Both Pass?}
    H -- Yes --> F
    H -- No --> I[Consignment Rejected]

This ensures reliable testing per IS 2686 for material conformity.

IS 2686: Quality Control - Key Points

Sampling (Clause 7.1 & Appendix C)

• Final sample ground to pass 150-micron IS sieve.
• Drying over steam-bath if necessary.
• Avoid excessive fineness during machine grinding.
• Sample tested as per specified tests.

Criteria for Conformity (Clause 7.2)

• Perform tests from Clauses 6.1 & 6.2.
• If failure occurs, repeat test on two more portions.
• If both pass, consignment accepted; if any fail, consignment rejected.

Sample Preparation (Clause 2.4)

• Wash sample with distilled water until chloride-free.
• Filter and ignite filter paper + content in silica capsule at 800°C for 15 min.
• Cool in desiccator, weigh for accurate mass.
• Use silica plate to prevent loss by shock heating.

Summary Table: Sampling & Testing Flow

flowchart TD
    A[Collect Sample] --> B[Grind to pass 150-micron sieve]
    B --> C{Dry if needed?}
    C -->|Yes| D[Steam Bath Drying]
    C -->|No| E[Wash with Distilled Water]
    D --> E
    E --> F[Filter Sample]
    F --> G[Ignite at 800°C for 15 min]
    G --> H[Cool & Weigh]
    H --> I[Test as per 6.1 & 6.2]
    I --> J{Pass?}
    J -->|No| K[Repeat test on 2 more portions]
    K --> L{Both pass?}
    L -->|Yes| M[Accept Consignment]
    L -->|No| N[Reject Consignment]
    J -->|Yes| M

IS 2686: Method for Determination of Sulphate Content (Appendix A, Clause 6.1)

Key Specifications:

• Maximum Sulphate Content: 1% (expressed as SO₃)
• Sample Preparation: Wash with distilled water until chloride-free.
• Filtration Methods: (a), (b), or (c) as per the code.

Procedure Summary:

1. Filtration: Filter the sample by one of the prescribed methods.
2. Ignition:
   • Fold wet filter paper and residue into a pre-weighed, ignited silica capsule.
   • Place capsule on silica plate inside a muffle furnace.
   • Heat at 800°C for 15 minutes.
   • Cool in a desiccator and weigh.
3. Drying (if method c used): Dry at 105 ± 5°C to constant mass.
4. Note: Ignition with wet paper yields more accurate results; silica plate prevents loss by shock heating.

Calculation:

[ \text{Sulphate content} (%) = \frac{\text{Mass of residue (SO}_3\text{)}}{\text{Mass of sample}} \times 100 ]

Summary Table:

flowchart TD
    A[Sample Preparation] --> B[Wash with distilled water]
    B --> C[Filtration (a/b/c)]
    C --> D{Method used?}
    D -->|a or b| E[Fold wet filter paper + residue into silica capsule]
    D -->|c| F[Dry crucible + precipitate at 105 ±5°C]
    E --> G[Ignite at 800°C for 15 min on silica plate]
    F --> G
    G --> H[

IS 2686 - Loss on Ignition (LOI) Determination

Key Formula (Clause 2.1, Appendix B)

[ \text{Loss on Ignition (%)} = \frac{\text{Loss in Mass}}{\text{Mass of Dry Sample}} \times 100 ]

Procedure Summary (Appendix B, Clause 6.2)

• Weigh ~1 g of dry sample in a pre-weighed silica dish.
• Ignite in a muffle furnace at 775 ± 25°C for 2 hours.
• Cover with a lid for the first 10 minutes.
• Cool in a desiccator and reweigh.
• Calculate % LOI using the formula above.

Acceptance Criteria (Clause 6.2, Appendix C)

Notes:

• LOI indicates organic content or moisture loss.
• Crucial for quality control of refractory materials.

flowchart TD
    A[Weigh ~1g Sample] --> B[Place in Silica Dish]
    B --> C[Ignite at 775 ± 25°C for 2 hrs]
    C --> D[Cover with lid for 10 mins]
    D --> E[Cool in Desiccator]
    E --> F[Reweigh Sample]
    F --> G[Calculate % LOI]

IS 2686 Sampling Details Summary

Sampling Procedure (Clause 7.1 & Appendix C)

• Sample must represent the proportions of coarse and fine material in the consignment.
• Initial sample size depends on consignment weight:

• Final sample is ground to pass 150-micron IS Sieve.
• Drying (if needed) done over a steam bath.
• Machine grinding should avoid excessive fineness.

Key Points

• Grinding ensures uniformity for testing.
• Representative sampling is critical to detect deleterious materials mostly in fines.
• Follow detailed procedure in Appendix C for sampling.

Sample Preparation Flow (Mermaid Diagram)

flowchart TD
    A[Consignment] --> B[Initial Sample (15-90 kg)]
    B --> C[Divide & Mix to represent coarse/fine proportions]
    C --> D[Final Sample]
    D --> E[Dry if needed over steam bath]
    E --> F[Grind to pass 150-micron IS Sieve]
    F --> G[Testing]

For complete procedure, refer to Appendix C of IS 2686.