broken brick (burnt clay) coarse aggregates for use in lime concrete

IS 3068: Scope - Key Formulas, Tables, and Specifications

1. Scope Overview

• Specifies requirements for broken brick coarse aggregate used in concrete.
• Defines test methods and limits for physical and chemical properties.

2. Key Specifications (Table 2: Broken Brick Coarse Aggregate Requirements)

3. Key Formulas

• Water Absorption (%) (Appendix A, Clause 4.1):

[ \text{Water absorption} = \frac{W_2 - W_1}{W_1} \times 100 ]

• (W_1) = mass of dry sample (g)

• (W_2) = mass after 24-hour immersion in water (g)

• Soluble Salts (%) (Clause 3.1):

[ \text{Soluble salts} = 10 \times W ]

• (W) = mass of dried material on the dish (g)

4. Rounding Off Values

• Follow IS 2-1960 for rounding test results.
• Retain the same significant figures as specified in the standard.

flowchart TD
    A[Broken Brick Aggregate] --> B[Tests]
    B --> C[Bulk Density (1100-1350 kg/m³)]
    B --> D[Aggregate Impact Value (Max 50%)]
    B --> E[Water Absorption (Max 20%)]
    B --> F[Water Soluble Matter (Max 1%)]
    E --> G[Formula: (W2 - W1)/W1 × 100]
    F --> H[Method: Appendix B]

IS 3068 Key References, Formulas & Tables Summary

Rounding Off Results (Clause 0.4)

• Final test values must be rounded per IS 2:1960.
• Retain the same number of significant figures as the specified value.

Table 2: Requirements for Broken Brick Coarse Aggregate (Clause 3.2)

Appendix A: Water Absorption Test

• Method updated to IS 1070:1992 (replacing IS 1070-1977).
• Procedure involves soaking aggregate and measuring weight gain.

Important References

• IS 2386 (Part 3): Specific gravity, density, voids, absorption, bulking for aggregates.
• IS 5640: Aggregate impact value test for soft coarse aggregates.

flowchart LR
    A[Broken Brick Aggregate] --> B[Bulk Density Test (IS 2386 Pt 3)]
    A --> C[Aggregate Impact Value Test (IS 5640)]
    A --> D[Water Absorption Test (IS 1070:1992)]
    A --> E[Water Soluble Matter Test (Appendix B)]

This concise overview helps ensure compliance with IS 3068 aggregate requirements.

IS 3068 - Definitions: Key Formulas & Tables

1. Rounding Off (Clause 0.4)

• Final test values must be rounded per IS 2-1960.
• Retain the same number of significant digits as the specified value.

2. Broken Brick Coarse Aggregate Requirements (Clause 3.2, Table 2)

3. Water Absorption Formula (Appendix A, Clause 4.1)

[ \text{Water Absorption (%)} = \frac{W_2 - W_1}{W_1} \times 100 ]

• ( W_2 ) = Mass after 24-hour immersion (g)
• ( W_1 ) = Dry mass (g)

4. Water Soluble Matter Formula (Appendix B, Clause 3.1)

[ \text{Soluble Salts (%)} = \frac{10W}{\text{mass of sample}} ]

• ( W ) = Mass of dried soluble material (g)

These definitions and formulas ensure compliance with IS 3068 for brick aggregate quality assessment.

IS 3068 Sampling - Key Points & Specifications

• Sampling Method: As per IS 2430-1969 (Specification for common burnt clay bricks).
• Sample Size: Minimum 3000 g aggregate for testing (Clause A-2.1).
• Rounding Off: Final test results should be rounded as per IS 2-1960 to match significant figures of specified values.

Table 2: Requirements for Broken Brick Coarse Aggregate (Clause 3.2)

Appendix A: Water Absorption Test Method (Summary)

• Use a sample ≥ 3000 g.
• Determine weight difference between saturated surface dry and oven-dry aggregate.
• Calculate water absorption (%) as:

[ \text{Water Absorption} = \frac{W_{ssd} - W_{dry}}{W_{dry}} \times 100 ]

Where:

• ( W_{ssd} ) = Weight in saturated surface dry condition
• ( W_{dry} ) = Oven dry weight

References for Test Methods:

• Bulk Density: IS 2386 (Part 3) - 1963
• Aggregate Impact Value: IS 5640 - 1970
• Water Absorption: Appendix A of IS 3068
• Water Soluble Matter: Appendix B of IS 3068

flowchart LR
    A[Sampling per IS 2430-1969] --> B[Collect ≥ 3000 g aggregate]
    B --> C[Test Bulk Density (IS 2386 Pt 3)]
    B --> D[Test Aggregate Impact Value (IS 5640)]
    B --> E[Test Water Absorption (Appendix A)]
    B --> F[Test Water Soluble Matter (Appendix B)]
    C & D & E

IS 3068: Grading Requirements for Broken Brick Coarse Aggregate

1. Grading (Clause 3.1 & Table 1)

• Grading shall conform to Table 1 (IS sieve sizes per IS:460 Part 1 - 1985).
• Sieve analysis conducted as per IS:2386 (Part 1) - 1963.

(Exact values from Table 1 of IS 3068)

2. Physical Properties (Clause 3.2 & Table 2)

3. Important Notes:

• Bulk Density: Indicates compactness; affects mix design.
• Aggregate Impact Value: Measures toughness; max 50% for broken brick aggregate.
• Water Absorption: High absorption (max 20%) affects water-cement ratio.
• Water Soluble Matter: Should be low (<1%) to avoid durability issues.

4. Water Absorption Test (Appendix A)

• Aggregate soaked in water for 24 hours.
• Absorption (%) = (\frac{\text{Saturated weight} - \text{Dry weight}}{\text{Dry weight}} \times 100)

flowchart TD
    A[Broken Brick Coarse Aggregate] --> B[Grading as per IS 3068 Table 1]
    A --> C[Physical Properties as per Table 2]
    C --> D[Bulk Density: 1100-1350 kg/m³]
    C

IS 3068: Physical Requirements for Broken Brick Coarse Aggregate

Key Specifications (Clause 3.2, Table 2)

Additional Physical Requirements

• Fines content (<4.75 mm sieve): Max 5% (Clause 2.2)
• Minimize handling of brick aggregate to avoid excessive fines.

Water Absorption Test (Appendix A)

• Procedure involves soaking aggregate, surface drying, and measuring weight gain.
• Formula for water absorption (WA):

[ WA% = \frac{(W_{saturated} - W_{dry})}{W_{dry}} \times 100 ]

Where:

• (W_{saturated}) = Weight of saturated surface dry aggregate
• (W_{dry}) = Oven dry weight of aggregate

Rounding Off Values (Clause 0.4)

• Final test values shall be rounded as per IS: 2-1960.
• Keep the number of significant digits same as specified values.

flowchart LR
    A[Brick Aggregate] --> B[Minimize Handling]
    B --> C[Limit Fines < 5% passing 4.75 mm sieve]
    A --> D[Physical Tests]
    D --> E[Bulk Density: 1100-1350 kg/m³]
    D --> F[Impact Value ≤ 50%]
    D --> G[Water Absorption ≤ 20%]
    D --> H[Water Soluble Matter ≤ 1%]

This summary ensures compliance with IS 3068 physical requirements for brick aggregates in concrete.

IS 3068: Key Test Methods & Formulas

1. Water Absorption of Aggregate (Clause 4.1, Appendix A)

• Formula:

[ \text{Water Absorption %} = \frac{W_2 - W_1}{W_1} \times 100 ]

Where:

• (W_1) = Mass of dry sample (g)

• (W_2) = Mass after 24-hour water immersion (g)

• Max Limit: 20% (Table 2, Item iii)

2. Water Soluble Matter in Aggregate (Appendix B)

• Max Limit: 1% (Table 2, Item iv)
• Follow detailed procedure in Appendix B for test preparation and measurement.

3. Other Key Aggregate Properties (Table 2)

4. Rounding Off Test Results (Clause 0.4)

• Round off values per IS 2:1960
• Retain significant figures as per specified values in IS 3068.

Summary Diagram: Test Flow for Water Absorption

flowchart TD
    A[Dry Aggregate Sample] --> B[Weigh (W1)]
    B --> C[Immerse in Water for 24 hrs]
    C --> D[Remove & Surface Dry]
    D --> E[Weigh (W2)]
    E --> F[Calculate Water Absorption %]

Note: Use IS 2386 (Part 3) for bulk density and IS 5640 for aggregate impact testing procedures.

IS 3068: Handling and Storage of Brick Aggregate – Key Points

Handling

• Minimize handling to reduce breakage and fines.
• Material passing 4.75 mm IS sieve must be ≤ 5%.

Physical Requirements (Table 2, Clause 3.2)

Water Absorption Test (Appendix A)

• Follow IS 3068 procedure.
• Results rounded as per IS 2-1960.

Summary for Storage:

• Store in dry, covered areas to prevent moisture absorption.
• Avoid contamination by soil or other materials.

flowchart TD
    A[Brick Aggregate] --> B[Minimize Handling]
    B --> C{Fines ≤ 5% passing 4.75 mm sieve?}
    C -- Yes --> D[Use in Concrete]
    C -- No --> E[Reject or Reprocess]
    D --> F[Store in Dry, Covered Area]

This ensures quality and durability of concrete using brick aggregate per IS 3068.

IS 3068: Evaluation and Reporting of Results - Key Points

Sample Preparation (Clause 3.1)

• Dry sample at 100–110°C to constant mass ( W_1 ).
• Immerse in distilled water (22–32°C) for 24 hrs.
• Remove surface water, weigh surface-dried sample ( W_2 ).

Water Absorption Calculation (Appendix A)

[ \text{Water Absorption (%)} = \frac{W_2 - W_1}{W_1} \times 100 ]

Water Soluble Matter (Clause B-2.1)

• Extract 25 g sample with distilled water for 4.5 hours.
• Filter and evaporate filtrate to dryness at 105–110°C.
• Calculate water soluble matter as percentage of original sample.

Reporting (Clause B-3)

• Round off results per IS 2-1960.
• Retain significant figures matching standard values.

Key Requirements (Table 2, Clause 3.2)

flowchart TD
    A[Dry Sample (W1)] --> B[Immerse in Water 24 hrs]
    B --> C[Surface Dry & Weigh (W2)]
    C --> D[Calculate Water Absorption %]
    D --> E[Report Results (Round per IS 2-1960)]

This summary aligns with IS 3068's evaluation and reporting requirements for broken brick aggregates.

IS 3068: Method for Determination of Water Absorption of Aggregate

Key Formula (Clause 4.1: A-4.1)

[ \text{Water Absorption (%)} = \frac{W_2 - W_1}{W_1} \times 100 ]

• W1 = Mass of dry sample (g)
• W2 = Mass of surface-dried sample after 24-hour water immersion (g)

Test Procedure Summary (Appendix A)

• Dry sample (~25 g) to constant mass at 100-110°C → weigh (W1).
• Immerse in distilled water (22-32°C) for 24 hours.
• Remove, surface dry quickly with damp cloth → weigh (W2).
• Calculate water absorption using above formula.

Requirements for Broken Brick Coarse Aggregate (Table 2, Clause 3.2)

Notes

• Use distilled water conforming to IS:1070-1977.
• Remove air bubbles by gentle agitation.
• Surface drying is crucial for accurate W2 measurement.

flowchart TD
    A[Dry Sample (W1)] --> B[Immerse in Water 24h]
    B --> C[Remove & Surface Dry]
    C --> D[Weigh Sample (W2)]
    D --> E[Calculate Water Absorption %]

This method ensures accurate determination of aggregate water absorption essential for quality control in masonry and concrete.

IS 3068: Method for Determination of Water Soluble Matter in Aggregate

Key Specifications & Procedure (Appendix B)

• Sample Preparation (B-2.1):
  • Weigh 25 g of aggregate sample.
  • Add 100 ml distilled water (IS:1070-1977).
  • Stir frequently for 3 hours.
  • Decant and filter through No. 42 Whatman paper.
  • Return filter paper to beaker, add 250 ml distilled water, continue extraction for 1.5 hours.
  • Wash filter paper 3 times, combine filtrates, make volume up to 500 ml.
  • Shake well, pipette 200 ml into a weighed dish.
  • Evaporate to dryness, heat at 105-110°C to constant mass.

Formula for Water Soluble Matter (B-3.1):

[ \text{Soluble salts, % by mass} = \frac{10 \times W}{\text{mass of sample (g)}} ]

• Where W = mass of dried residue in the dish (g).

Water Absorption Formula (Clause 4.1):

[ \text{Water absorption %} = \frac{W_2 - W_1}{W_1} \times 100 ]

• (W_1) = dry mass (g)
• (W_2) = mass after 24-hour water immersion (g)

Summary Flow (Mermaid Diagram):

flowchart TD
    A[Weigh 25g sample] --> B[Add 100 ml distilled water]
    B --> C[Stir for 3 hours]
    C --> D[Filter through No.42 paper]
    D --> E[Return filter paper + 250 ml water]
    E --> F[Extract for 1.5 hours]
    F --> G[Wash filter paper 3 times]
    G --> H[Combine filtrates to 500 ml]
    H --> I[Shake and pipette 200 ml]
    I --> J[Evaporate to dryness at 105-110°C]
    J --> K[Weigh residue W]
    K --> L[Calculate % soluble salts]

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