Specification for Artificial Lightweight Aggregates for Concrete Masonry Units

IS 9142: Scope & Key Specifications for Lightweight Combined Aggregates

Scope (Clause 3.1)

• Defines grading requirements for lightweight combined aggregates used in concrete masonry units.
• Grading is based on particle size distribution via sieve analysis.

Key Table: Grading Requirements (Table 1)

Additional Notes:

• Fine aggregate size: 0 to 4.75 mm
• Coarse aggregate size: 4.75 to 12.5 mm or 2.36 to 10 mm
• Combined aggregate covers 0 to 10 mm

Bulk Density (Clause 4)

• Bulk density is a key physical property but details are in later clauses.

This grading ensures proper particle size distribution for lightweight concrete masonry units, optimizing strength and workability.

IS 9142: General Characteristics of Lightweight Aggregates for Concrete Masonry Units

1. Grading Requirements (Clause 3.1, Table 1)

2. Bulk Density (Clause 4.2)

• Bulk density uniformity: Successive supplies must not vary by more than ±10% from the accepted sample.

3. Deleterious Substances

• Aggregates must be free from harmful materials affecting strength and durability (refer to IS 9142 for limits).

Summary:

• Grading controls particle size distribution for structural performance.
• Bulk density consistency ensures uniform concrete quality.
• Cleanliness of aggregates is critical.

flowchart LR
    A[Aggregate Supply] --> B{Sieve Analysis}
    B -->|Passes Grading| C[Accept Supply]
    B -->|Fails Grading| D[Reject Supply]
    C --> E[Check Bulk Density]
    E -->|Within ±10%| F[Use in Concrete]
    E -->|Outside ±10%| D

This ensures quality lightweight aggregate for masonry units per IS 9142.

IS 9142: Materials for Lightweight Aggregates in Concrete Masonry Units

1. Grading Requirements (Clause 3.1, Table 1)

• Percentages indicate mass passing through IS sieves.

2. Bulk Density (Clause 4.2)

• Bulk density of lightweight aggregate supplies shall not differ by more than ±10% from the sample accepted.

3. Deleterious Substances (Clause 5)

• Aggregates must be free from harmful materials affecting durability and strength.

Summary:

• Use Table 1 for particle size distribution control.
• Maintain uniform bulk density within 10% tolerance.
• Ensure aggregates are clean and free from deleterious substances.

This ensures consistent quality and performance of lightweight aggregates in masonry units.

IS 9142 Key Points on Bulk Density of Lightweight Aggregates

• Bulk Density (Loose) Test:
  Per Clause 7.3, test aggregates in oven-dry condition as per IS 2386 (Part III)-1963, which covers specific gravity, density, voids, absorption, and bulking.

• Limits on Bulk Density:

  • Clause 4.1: Dry loose bulk density of combined aggregate ≤ 1100 kg/m³.
  • Clause 4.2: Bulk density variation between successive supplies should not exceed ±10% of the acceptance sample.

Bulk Density Testing Summary (IS 2386 Part III)

Formula for Bulk Density (Loose)

[ \text{Bulk Density} = \frac{\text{Mass of oven-dry aggregate}}{\text{Volume of container}} ]

flowchart LR
    A[Sample Preparation] --> B[Oven Drying]
    B --> C[Fill Container Loosely]
    C --> D[Measure Mass]
    C --> E[Measure Volume]
    D & E --> F[Calculate Bulk Density]

Summary: IS 9142 mandates oven-dry loose bulk density ≤ 1100 kg/m³ with ±10% uniformity, tested as per IS 2386 (Part III).

IS 9142: Deleterious Substances in Lightweight Aggregates

Key Specifications & Limits

• Clause 5.1: Lightweight aggregates must not contain excessive deleterious substances.
• Clause 5.1.1: Organic Impurities
  • Test: Colorimetric test for organic impurities.
  • Rejection Criteria: If color is darker than standard, reject unless proven harmless.
• Clause 7.8: Sulphate Content
  • Test as per IS 4032-1968.
  • Limits: Typically, sulphate content should be within limits safe for lime concrete (usually <0.5% SO₄²⁻).

Uniformity of Mass (Clause 4.2)

• Bulk density variation between successive supplies must be ≤ 10% of the accepted sample.

Summary Table: Deleterious Substances Limits

Notes:

• Supplier's Certificate (Clause 8) is mandatory to certify compliance.
• Tests for deleterious substances ensure durability and strength of lime concrete.

flowchart TD
    A[Lightweight Aggregate] --> B{Test for Deleterious Substances}
    B --> C[Organic Impurities Test]
    B --> D[Sulphate Content Test]
    C --> E{Color ≤ Standard?}
    E -->|Yes| F[Accepted]
    E -->|No| G[Rejected or Further Analysis]
    D --> H{SO₄²⁻ ≤ Limit?}
    H -->|Yes| F
    H -->|No| G

This ensures lightweight aggregates are safe and consistent for lime concrete use.

IS 9142: Requirements for Concrete Masonry Units - Key Specifications

1. Aggregate Grading (Clause 3.1, Table 1)

The grading of lightweight aggregates for concrete masonry units must follow the particle size distribution below (% passing by mass):

2. Key Points:

• Use sieve analysis to confirm particle size distribution.
• Proper grading ensures workability, strength, and durability of masonry units.
• Artificial lightweight aggregates must comply with these gradations for consistent quality.

This grading table guides the selection and proportioning of aggregates for manufacturing quality concrete masonry units under IS 9142.

IS 9142: Methods of Sampling and Test for Lightweight Aggregate Properties

Key Specifications & Tables

1. Sulphate Content

• Max SO₃ content = 1% by mass (Clause 6.1.2)

2. Sampling (Clause 7.1)

• Follow IS 2430-1969 for sampling lightweight aggregates.

3. Grading (Clause 7.2)

• Conduct sieve analysis as per IS 2386 (Part I) - 1963.
• Particle size distribution must conform to Table 1 below:

Summary of Test Methods

• Sampling: IS 2430-1969
• Grading: IS 2386 (Part I)-1963
• Sulphate Content: Chemical test ensuring ≤ 1% SO₃

flowchart TD
    A[Sampling] -->|IS 2430-1969| B[Sample Collection]
    B --> C[Grading Test]
    C -->|IS 2386 Part I| D[Sieve Analysis]
    D --> E[Check % Passing per Table 1]
    A --> F[Sulphate Content Test]
    F -->|Chemical Analysis| G[SO₃ ≤ 1%]

This ensures lightweight aggregate quality for concrete masonry units per IS 9142.

IS 9142: Supplier’s Certificate and Cost of Tests (Clause 8)

Key Specifications:

• Supplier’s Certificate (8.1):
  Supplier must ensure material complies with IS 9142 and provide a certificate if requested.

• Material Supply for Tests (8.3):
  Supplier shall provide test samples free of charge.

• Cost of Tests (8.4):

  Condition	Cost borne by
  Material does not comply	Supplier
  Material complies	Purchaser

Related Standards for Tests:

• Sulphate content: IS 4032-1968
• Methods for aggregates: Part II (Deleterious materials & organic impurities)
• Chemical analysis of hydraulic cement
• Lightweight concrete blocks specification

Summary Table for Cost Responsibility:

This ensures accountability and quality assurance in material supply and testing under IS 9142.