inorganic aggregates for use in gypsum plaster

IS 9498: Scope and Key Specifications

• Scope: Covers lightweight aggregates—Perlite, Vermiculite, and Sand—used in construction.

Key Table: Grading Requirements (Clause 3.1, Table 1)

• Rounding Off: Test results must be rounded per IS 2-1960, retaining the same significant figures as specified.

This grading ensures proper particle size distribution for lightweight aggregates, essential for structural and thermal performance.

IS 9498 Definitions & Key Specifications

1. Definitions (Clause 2.0)

• The standard defines terms related to lightweight aggregates like perlite, vermiculite, and sand used in lightweight concrete.

2. Grading Requirements (Clause 3.1 & Table 1)

• Aggregates must conform to specified grading limits based on sieve analysis.
• Sieve sizes and percentage retained (cumulative) limits are given for Perlite, Vermiculite (by volume), and Sand (by mass):

3. Rounding Off (Clause 0.3)

• Test results must be rounded per IS 2-1960, maintaining the same significant figures as specified values.

This ensures uniformity and quality control in lightweight aggregate grading, critical for concrete performance.

IS 9498 Key Requirements for Aggregate Grading (Clause 3.1 & Table 1):

• Sieve Analysis: Aggregate grading must conform to limits in Table 1 for Perlite, Vermiculite, and Sand.

• Rounding Off: Test results must be rounded as per IS 2-1960, retaining the same significant figures as specified.

• Material Evaluation: Purchasers may reject materials based on minimum mass or approximate volume criteria (Clause 9.1).

Summary:

• Use sieve sizes and percentage retained limits to verify aggregate grading.
• Follow IS 2-1960 for rounding test results.
• Material acceptance can be volume or mass-based.

flowchart LR
    A[Sieve Analysis] --> B{Aggregate Type}
    B --> C[Perlite]
    B --> D[Vermiculite]
    B --> E[Sand]
    C --> F[Check % Retained per Table 1]
    D --> F
    E --> F
    F --> G[Conforms?]
    G -->|Yes| H[Accept Material]
    G -->|No| I[Reject Material]

This ensures compliance with IS 949

IS 9498: Physical Properties of Aggregates – Key Points

1. Grading Requirements (Clause 3.1, Table 1)

2. Sieve Analysis Procedure (Clause 7.1)

• Sample volume: ~500 ml bulk volume
• Sieving time: 5 minutes (mechanical sieve)
• Measure volume of each fraction in a 250 ml graduated cylinder
• Pour aggregate loosely, level surface, read volume within ±2 ml
• Percentage retained on each sieve = sum of volumes of all fractions larger than that sieve expressed as % of total volume

3. Additional Notes

• Sieve analysis follows IS 2386 (Part I) - 1963, modified for volume measurement instead of mass for lightweight aggregates.
• Volume-based grading is essential for lightweight aggregates like perlite and vermiculite.

flowchart TD
    A[Sample ~500 ml] --> B[Mechanical Sieving - 5 min]
    B --> C[Collect sieve fractions]
    C --> D[Measure volume in 250 ml cylinder]
    D --> E[Calculate % retained per sieve]
    E --> F[Compare with Table 1 limits]

This ensures aggregates meet grading and physical property requirements

IS 9498: Chemical Requirements for Aggregates

Key Specifications (Clause 7.4: Water-Soluble Impurities)

• Sample: 10 g of sand
• Procedure:
  • Add 100 ml distilled water, boil and simmer for 5 min
  • Filter and wash with hot distilled water to ~125 ml filtrate
  • Evaporate to dryness (max 120°C)
  • Cool in desiccator, weigh residue
• Result:
  [ \text{Water-Soluble Impurities (%)} = \frac{\text{Mass of residue (g)}}{10 \text{ g}} \times 100 ]

Grading Limits (Clause 3.1, Table 1)

Notes:

• Round off test results as per IS 2-1960.
• Ensure residue drying temperature does not exceed 120°C.

flowchart TD
    A[10 g Sample] --> B[Add 100 ml Distilled Water]
    B --> C[Boil & Simmer 5 min]
    C --> D[Filter & Wash to 125 ml]
    D --> E[Evaporate to Dryness (<120°C)]
    E --> F[Cool & Weigh Residue]
    F --> G[Calculate % Water-Soluble Imp

IS 9498 Sampling Key Points & Tables

Sampling Procedure (Clauses 6.2 & 6.3)

• Bagged aggregates:

  • Sample at least 1 bag per 100 bags, minimum 6 bags per shipment ≥100 bags.
  • For smaller shipments, sample 6% of bags.
  • Use a sampling tube inserted diagonally full length in a horizontal bag.
  • Combine portions to form a gross sample ≥ 28 dm³.
  • Prepare and test 1 composite sample per 2000 bags.

• Sample reduction:

  • Use quartering or riffling to reduce gross samples to test size.

Grading Requirements (Table 1, Clause 3.1)

Rounding Off (Clause 0.3)

• Final test values must be rounded per IS 2:1960, matching significant figures of specified values.

flowchart TD
    A[Start: Shipment of Bagged Aggregates] --> B[Randomly select bags per Clause 6.2]
    B --> C[Use sampling tube diagonally in bags]
    C --> D[Combine portions to form gross sample ≥ 28 dm³]
    D --> E[Reduce sample by quartering or riffling

IS 9498: Methods of Test - Key Points & Tables

Sample Preparation (Clause 6.3)

• Samples must be reduced by quartering or riffling to obtain proper size for testing.

Sieve Analysis (Clause 3.1 & Table 1)

• Aggregates must meet grading limits specified below (percentage retained, cumulative):

Package Rejection Criteria (Clause 9.2)

• Reject if:
  • Mass is 5% less than indicated.
  • Volume is 10% less than indicated.

Additional Notes

• Follow IS 2-1960 for rounding test results.
• Refer to IS methods for:
  • Specific gravity, density, voids, absorption, bulking (Part III).
  • Deleterious materials & organic impurities (Part II).

flowchart TD
    A[Sample Collection] --> B[Sample Reduction]
    B --> C[Quartering or Riffling]
    C --> D[Sieve Analysis]
    D --> E[Check Grading Limits (Table 1)]
    E --> F{Within Limits?}
    F -- Yes --> G[Accept Sample]
    F -- No --> H[Reject Sample]

This summarizes the key testing methods and grading requirements per IS 9498.

IS 9498: Packing and Marking of Lightweight Aggregates

Key Specifications (Clause 8 & 9)

• Marking on Packages (8.1):

  • Manufacturer's name
  • Type of aggregate
  • Minimum mass (weight)
  • Approximate volume of contents

• Rejection Criteria (Clause 9):

  • Individual Package Rejection (9.2):
    • Mass < 95% of marked weight → Reject package
    • Volume < 90% of marked volume → Reject package
  • Shipment Rejection (9.3):
    • Average of 2 packages per 100 (min 6 packages) mass < marked weight → Reject shipment
    • Average volume differs by > +5% or < -10% from marked volume → Reject shipment

Water-Soluble Impurities Test (Clause 7.4)

• Sample: 10 g sand + 100 ml distilled water, boiled 5 min
• Filter, wash, evaporate at ≤120°C
• Calculate residue % = (Mass of residue / 10 g) × 100

Summary Table: Packing & Marking Criteria

flowchart TD
    A[Package] --> B{Marking}
    B -->|Manufacturer| C[Name]
    B -->|Aggregate Type| D[Type]
    B -->|Mass| E[Min Mass]
    B -->|Volume| F[Approx Volume]
    A --> G{Quality Check}
    G -->|Mass < 95%| H[Reject Package]
    G -->|Volume < 90%| H
    G -->|Pass| I[Accept Package]
    subgraph Shipment
        J[Random Sampling: 2 pkgs/100, min 6 pkgs]
        J --> K{Avg Mass & Volume}
        K -->|Mass < Marked| L[Reject Shipment]
        K -->|Vol > +5% or < -10%

IS 9498: Inspection and Rejection Criteria Summary

Key Clauses for Inspection & Rejection

• Clause 9.1: Purchaser may reject materials based on minimum mass or approximate volume.

• Clause 9.2 (Individual Package Rejection):

  • Reject if mass is 5% less than indicated.
  • Reject if volume is 10% less than indicated.

• Clause 9.3 (Shipment Rejection):

  • Reject entire shipment if average of two packages per 100 (minimum 6 packages) is:
    • Less than the indicated mass.
    • Volume differs by more than +5% or -10% from indicated volume.

Sampling Procedure

• Randomly select 2 packages per 100 or at least 6 packages.
• Calculate average mass/volume for evaluation.

Grading Table (Clause 3.1, Table 1 Excerpt)

Summary Diagram: Inspection Flow

flowchart TD
    A[Start: Receive Shipment] --> B[Select Random Samples (2 per 100, min 6)]
    B --> C{Check Mass & Volume}
    C -->|Mass < 95% indicated| D[Reject Individual Package]
    C -->|Volume < 90% indicated| D