Cinder as Fine Aggregates for use in Lime Concrete
1977 Edition

Overview of Scope (Clause 2.0)

Defines the applicability limits of this standard relating to the properties and testing of cinder aggregates used in lime concrete.

Sampling Guidelines (Clauses 2.4 & 7.1)

• Sample Preparation:

  • Final test samples must be ground finely enough to pass a 150-micron IS sieve.
  • Drying performed over a steam bath when necessary.
  • Mechanical grinding should be carefully controlled to prevent overly fine particles altering test results.

• Sampling Details:

  • Refer to Appendix C for comprehensive sampling procedures.

Sulphate Content Testing (Appendix A, Clause 6.1)

Specifies the method for determining sulphate content to ensure aggregate durability.

Sampling Procedure Summary

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

Definitions and Sampling (Clauses 2.0 & 2.4)

• Establishes the terminology used within the standard to maintain clarity.
• Specifies that the final sample must fully pass through a 150-micron IS sieve.
• Drying, if needed, is performed over a steam bath to prevent sample alteration.
• Mechanical grinding is permitted but must avoid producing particles finer than 150 microns.
• The prepared sample is then ready for testing.

Sampling Specifications

Sampling Process Diagram

flowchart TD
    A[Collected Sample] --> B[Steam Bath Drying if Needed]
    B --> C[Careful Grinding]
    C --> D[Pass Through 150-micron IS Sieve]
    D --> E[Sample Ready for Testing]

Classification Categories (Clause 4.1)

• Class A: Suitable for general construction applications.
• Class B: Intended for interior areas not subject to moisture.
• Class C: Designed for precast concrete blocks.

Grading Specifications (Clause 5.1)

• These represent average grading values; further crushing may be performed to meet specific project requirements.

Additional Notes

• Soundness testing is omitted as per the current revision.
• Rounding off of test results should follow IS 2-1960 guidelines.

This classification ensures the appropriate selection of cinder aggregates based on exposure and intended structural use.

Sampling Protocols (Clauses 7.1 & Appendix C)

• The sample must accurately reflect the coarse and fine fractions of the lot.
• Sample Size Guidelines:
  • For consignments of 5 to 10 tonnes: 15 to 20 kg.
  • For consignments exceeding 50 tonnes: 45 to 90 kg.
  • Intermediate quantities should be scaled proportionally.

Sample Preparation

• Final samples are ground to completely pass through a 150-micron IS sieve.
• Drying over steam bath is carried out if necessary.
• Mechanical grinding should avoid over-fineness.

Sampling Size Table

Process Flow

flowchart TD
    A[Consignment] --> B[Sample Collection]
    B --> C[Grinding to pass 150-micron sieve]
    C --> D[Drying (Steam bath if required)]
    D --> E[Sample Ready for Testing]

Particle Size Distribution (Clause 5.1)

Key Points

• Grading ensures suitable particle size distribution for workability and strength.
• Aggregates may be further crushed to fulfill project-specific needs.
• These values are averages; actual grading can vary.
• Test results should be rounded in accordance with IS 2-1960.

Aggregate Classes (Clause 4.1)

• Class A: General use
• Class B: Interior, dry conditions
• Class C: Precast blocks

Grading Curve Illustration

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[Finer Particles]

Grading Details (Clause 5.1)

Sampling and Preparation (Clause 2.4)

• Samples must fully pass the 150-micron sieve.
• Drying is done using a steam bath if necessary.
• Avoid excessive fineness during grinding.

Key Specifications

• Aggregates should meet the grading requirements to be suitable for lime concrete.
• Proper sample preparation is essential for accurate testing.

This guarantees consistency and quality control for cinder aggregates as per the standard.

Sample Preparation (Clause 2.4)

• Grind the sample to pass through a 150-micron IS sieve.
• Dry over steam bath if required.
• Avoid over-grinding.

Sulphate Content Test (Appendix A, Clause 6.1)

• Rinse the sample with distilled water until no chloride remains.
• Filter the sample and fold wet filter paper with residue into an ignited silica capsule.
• Ignite at 800°C for 15 minutes on a silica plate.
• Cool in a desiccator and weigh.
• For method (c), dry precipitate at 105 ± 5°C to constant mass after filtration.

Conformity Criteria (Clause 7.2)

• If the initial test fails, repeat on two additional samples.
• Accept consignment if both retests pass; reject if any fail.

Testing Summary Table

flowchart TD
    A[Sample Collection] --> B[Grinding to 150-micron sieve]
    B --> C[Steam Bath Drying if required]
    C --> D[Testing Sulphate Content]
    D --> E{Pass Initial Test?}
    E -- Yes --> F[Consignment Accepted]
    E -- No --> G[Repeat Test on 2 More Samples]
    G --> H{Both Retests Pass?}
    H -- Yes --> F
    H -- No --> I[Consignment Rejected]

Sampling and Preparation (Clauses 7.1, 2.4 & Appendix C)

• Samples must be ground to pass a 150-micron sieve.
• Steam bath drying applied if necessary.
• Avoid excessive grinding.

Testing and Acceptance (Clause 7.2)

• Conduct tests as per Clauses 6.1 and 6.2.
• Upon failure, repeat tests on two additional portions.
• Accept consignment only if two out of three tests pass.

Sample Cleaning and Ignition

• Wash sample with distilled water to remove chlorides.
• Filter and ignite in silica capsule at 800°C for 15 minutes.
• Cool in desiccator before weighing.
• Use of silica plate prevents loss from sudden heating.

Quality Control Workflow

flowchart TD
    A[Sample Collected] --> B[Grind to 150-micron sieve]
    B --> C{Dry 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 and Weigh]
    H --> I[Test as per standard]
    I --> J{Pass?}
    J -- No --> K[Repeat on two samples]
    K --> L{Both pass?}
    L -- Yes --> M[Accept]
    L -- No --> N[Reject]
    J -- Yes --> M

Sulphate Content Limits and Test Method (Appendix A, Clause 6.1)

• Maximum allowable sulphate content is 1% expressed as SO₃.
• Sample is washed with distilled water until free from chlorides.
• Filtration is conducted by one of the prescribed methods (a, b, or c).

Testing Steps

1. Filter the sample using the specified method.
2. Fold the wet filter paper with the residue into a pre-weighed, ignited silica capsule.
3. Place the capsule on a silica plate inside a muffle furnace.
4. Ignite at 800°C for 15 minutes.
5. Cool in a desiccator and weigh.
6. If method (c) is used, dry the precipitate at 105 ± 5°C to constant weight before weighing.

Calculation Formula

[ \text{Sulphate Content (%) } = \left(\frac{\text{Mass of SO}_3}{\text{Mass of Sample}}\right) \times 100 ]

Summary Table

flowchart TD
    A[Prepare Sample] --> B[Wash with Distilled Water]
    B --> C[Filter Using Method (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 and Precipitate at 105 ± 5°C]
    E --> G[Ignite at 800°C for 15 min on Silica Plate]
    F --> G
    G --> H[Cool and Weigh]

LOI Calculation (Clause 2.1, Appendix B)

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

Testing Method (Appendix B, Clause 6.2)

• Weigh approximately 1 g of dry sample into a pre-weighed silica crucible.
• Ignite in a muffle furnace at 775 ± 25°C for 2 hours.
• Cover with a lid during the initial 10 minutes.
• Cool in a desiccator and reweigh.
• Calculate the percentage loss on ignition.

Maximum Allowable LOI by Class (Clause 6.2 & Appendix C)

Notes

• LOI reflects organic content or moisture loss.
• This test is essential for quality assessment of refractory aggregates.

flowchart TD
    A[Weigh ~1g Sample] --> B[Place in Silica Crucible]
    B --> C[Ignite at 775 ± 25°C for 2 Hours]
    C --> D[Cover with Lid for 10 Minutes]
    D --> E[Cool in Desiccator]
    E --> F[Reweigh and Calculate LOI]

Sampling Guidelines (Clauses 7.1 & Appendix C)

• Samples must reflect the proportional presence of coarse and fine materials in the batch.
• Initial sample size recommendations based on consignment weight:

• Final samples are ground to pass fully through a 150-micron IS sieve.
• Drying, if needed, is performed over a steam bath.
• Machine grinding should not produce excessive fineness.

Important Points

• Grinding ensures sample uniformity for testing.
• Representative sampling is vital to detect harmful constituents mainly found in fine fractions.

Sampling Process Flow

flowchart TD
    A[Consignment] --> B[Initial Sample (15-90 kg)]
    B --> C[Division and Mixing to Represent Coarse/Fine Ratios]
    C --> D[Final Sample]
    D --> E[Steam Bath Drying if Required]
    E --> F[Grinding to Pass 150-micron Sieve]
    F --> G[Testing]