Separation occurs as a granular sample moves through a vertical stack arranged with progressively smaller openings. Controlled shaking allows particles to pass through openings large enough to accommodate them, while larger particles remain on higher sieves. Weighing the material retained at each level converts the physical separation into a particle-size distribution for engineering evaluation.
Percentage retained shows how much material remains on each sieve, while percentage passing indicates the portion that moves through a given opening. Together, these values describe gradation, or the distribution of particle sizes within the sample. Engineers can use the resulting pattern to assess whether soil, aggregate, sand, or powder is relatively uniform and suitable for its intended use.
Gradation affects how granular materials behave when placed or combined. The distribution of particle sizes helps engineers evaluate characteristics related to compaction, drainage, and permeability, which in turn influence overall material performance. This information supports decisions about whether a soil or aggregate can meet functional requirements in construction applications.
A representative granular sample is placed in the stacked sieves and subjected to controlled shaking. After separation, the mass retained on each sieve is measured. Those measurements are used to calculate percentage retained and percentage passing, producing gradation results that can be interpreted for material classification, uniformity assessment, mixture design, or quality verification.
Engineers apply the method to soils, aggregates, sand, and powders when they need evidence about particle-size characteristics. The results help classify soils and aggregates, assess material uniformity, design concrete and asphalt mixtures, and verify quality before construction use. These applications connect laboratory measurements with decisions about expected material behavior and performance.
For concrete and asphalt, particle-size results show how the aggregate or sand is distributed across sieve openings. Engineers can use this gradation information when designing mixtures and checking whether materials meet the intended particle-size requirements. Verification also helps identify unsuitable or inconsistent material before it affects construction quality or mixture performance.