Overview
ISO 20290-5:2023 - "Aggregates for concrete - Test methods for mechanical and physical properties - Part 5: Determination of particle size distribution by sieving method" defines a reference washing and dry sieving method for determining the particle size distribution (PSD) of aggregates. It applies to all aggregates (including lightweight aggregates) up to 90 mm nominal size, excluding filler. The document sets out the principle, apparatus, sample preparation, washing and sieving procedures, calculation, validation and reporting requirements used for testing and dispute resolution.
Key Topics and Technical Requirements
- Test methods: Two permissible approaches - washing followed by dry sieving, or direct dry sieving where washing would cause agglomeration or alter lightweight aggregate properties.
- Critical sieve size: A 0.063 mm test sieve must be included in the series; washing continues until the water passing this sieve is clear.
- Apparatus and tolerances: Test sieves shall conform to ISO 3310‑1 / ISO 3310‑2 and ISO 565. Use ventilated oven (100 °C to 115 °C) for drying and balances accurate to ±0.1% of the test portion mass.
- Sample preparation: Samples must be reduced by quartering or a sample divider to meet minimum test portion masses (Table 1). Dry test portions to constant mass before analysis.
- Sieving procedure: Arrange sieves from largest to smallest, avoid overloading (area/aperture guidance provided), and continue sieving until retained masses change by no more than 1.0% by mass.
- Calculations & validation: Report individual and cumulative percentages passing each sieve. For the 0.063 mm fraction, a specific formula is given to calculate fines. Sum of retained masses and pan material must be within 1% of the original mass (otherwise repeat the test).
- Reporting: Test reports must reference ISO 20290‑5:2023 and include sample ID, lab ID, method used (washing/dry sieving), cumulative percentages (with specified precision), deviations and any unusual observations.
Applications and Who Uses It
ISO 20290-5:2023 is used by:
- Materials testing laboratories performing PSD analysis for aggregates.
- Concrete producers and quality control teams verifying aggregate grading for mix design and compliance.
- Construction contractors and civil engineers ensuring specified aggregate gradation in structural and pavement works.
- Regulatory bodies and dispute resolution panels relying on the reference method for formal comparisons.
Practical uses include mix proportioning, verifying compliance with specifications, quality assurance of incoming aggregates, and providing authoritative test data in contractual disputes.
Related Standards
- ISO 3310‑1, ISO 3310‑2 - Test sieves technical requirements
- ISO 565 - Nominal sizes of sieve openings
- Other parts of the ISO 20290 series addressing different aggregate test methods
Keywords: ISO 20290-5:2023, particle size distribution, sieving method, aggregates for concrete, test sieves, washing and dry sieving, 0.063 mm sieve, aggregate testing, quality control.