Geotechnical ASTM 2017 Edition

ASTM D6913 — Sieve Analysis for Particle-Size Distribution

Standard test methods for determining the particle-size distribution (gradation) of soils using sieve analysis, from 125 mm down to 75 μm (No. 200) sieve.

Scope

ASTM D6913-17 covers the quantitative determination of the particle-size distribution of mineral soils using dry or wet mechanical sieving. The method applies to soils with particles ranging from 125 mm (5 inches) down to 75 μm (No. 200 sieve). For particles smaller than 75 μm, a hydrometer analysis (ASTM D7928) is required. The test provides the fundamental grain-size data needed for soil classification (ASTM D2487), filter design, compaction control, and pavement material evaluation.

The standard specifies two procedures: dry sieving, which is suitable for non-plastic soils and soils with negligible fines content; and wet sieving, which is required for soils containing plastic fines that would adhere to coarser particles during dry sieving, producing erroneous results. The choice between dry and wet sieving depends on the soil type and the intended use of the gradation data.

[FIGURE — Stack of sieves on a mechanical shaker showing nested arrangement from coarse at top to fine at bottom]

Purpose

Particle-size distribution is one of the most fundamental index properties of soil. The gradation curve defines the relative proportions of gravel, sand, silt, and clay-sized particles, which in turn govern many engineering behaviors. The purpose of ASTM D6913 is to produce a reliable, repeatable measurement of the grain-size distribution that can be used for soil classification, material specification, and design parameter estimation. The uniformity coefficient (CU) and coefficient of curvature (CC) derived from the gradation curve are used in the USCS to distinguish well-graded from poorly-graded soils — a distinction that has direct implications for compaction characteristics, drainage behavior, and liquefaction potential.

Engineering Applications

  • Soil classification — providing primary data for USCS (ASTM D2487) and AASHTO (ASTM D3282) classification systems
  • Filter design — selecting filter materials for earth dams and drainage systems using D15 and D85 ratios
  • Pavement materials — evaluating base and subbase aggregates against grading specifications (e.g., ASTM D2940, AASHTO M147)
  • Concrete aggregate grading — verifying fine and coarse aggregate gradation per ASTM C33
  • Permeability estimation — using D10 (effective size) for Hazen's approximation of hydraulic conductivity
  • Liquefaction assessment — identifying gradation characteristics associated with liquefaction susceptibility
  • Compaction optimization — well-graded soils (high CU) achieve higher densities than poorly-graded soils
  • Erosion control — evaluating soil erodibility based on gradation and fines content

Design Philosophy

Sieve analysis is based on the straightforward principle of mechanical separation by size: a soil sample is passed through a stack of sieves with progressively smaller openings, and the mass retained on each sieve is weighed to determine the percentage passing each size. The standard uses a square-root-of-two progression of sieve sizes (4:1 area ratio between successive sizes), providing approximately equal resolution on a logarithmic scale. This geometric progression ensures that the gradation curve has adequate detail across the full range of particle sizes.

The gradation curve (plotted as percent passing vs particle size on a semi-logarithmic chart) provides a complete description of the particle-size distribution from which D10, D30, D60, CU, and CC are derived. These parameters describe not just the central tendency of the particle sizes but the shape of the distribution curve, which governs packing behavior and therefore mechanical properties. A well-graded soil (CU ≥ 4 for gravel, ≥ 6 for sand, and CC between 1 and 3) has particles spanning a wide size range, allowing smaller particles to fill the voids between larger ones — producing higher density and greater stability.

Percent retained on sieve n:  Rn = (mass retainedn / total mass) × 100%

Cumulative percent passing:  Pn = 100% − ΣRi (for i = 1 to n)

Uniformity coefficient:  CU = D60 / D10

Coefficient of curvature:  CC = D30² / (D60 × D10)

Well-graded gravel:  CU ≥ 4 AND 1 ≤ CC ≤ 3
Well-graded sand:  CU ≥ 6 AND 1 ≤ CC ≤ 3

Important Requirements

The test requires a set of standard sieves conforming to ASTM E11 specifications, a mechanical sieve shaker, an oven for drying samples, and a balance with sensitivity of 0.01 g for fine fractions and 0.1 g for coarse. The minimum sample mass depends on the maximum particle size — for example, 100 g minimum for soils with 100% passing No. 10 (2 mm), 500 g for soils with particles up to 9.5 mm, and 5000 g for soils with particles up to 75 mm.

US Standard Sieve Sizes

Sieve Designation Opening Size US Mesh No. Soil Fraction
3 in 75 mm — Cobbles / gravel
3/4 in 19 mm — Coarse gravel
No. 4 4.75 mm 4 Gravel / sand boundary
No. 10 2.00 mm 10 Coarse sand
No. 20 850 μm 20 Medium sand
No. 40 425 μm 40 Fine sand
No. 60 250 μm 60 Fine sand
No. 100 150 μm 100 Very fine sand
No. 200 75 μm 200 Sand / fines boundary

Key Parameters

Parameter Symbol Definition Engineering Significance
Effective size D10 Particle size at 10% passing Used in Hazen permeability estimate, filter design
30% passing size D30 Particle size at 30% passing Required for CC calculation
60% passing size D60 Particle size at 60% passing Required for CU and CC calculation
Uniformity coefficient CU D60 / D10 Measures gradation width; higher = more well-graded
Coefficient of curvature CC D30²/(D60×D10) Measures gradation shape; 1–3 = well-graded
Percent gravel % > 4.75 mm Retained on No. 4 sieve Defines coarse fraction in USCS
Percent sand % 75 μm – 4.75 mm Passing No. 4, retained on No. 200 Sand fraction for classification
Percent fines % < 75 μm Passing No. 200 sieve Critical for USCS classification decision

Gradation Curve Interpretation

The gradation curve plots particle diameter (log scale) on the horizontal axis versus percent passing (arithmetic scale) on the vertical axis. The shape of the curve provides immediate visual insight into the soil characteristics. A steep curve indicates a uniform (poorly-graded) soil with particles in a narrow size range. A flat curve spanning a wide size range indicates a well-graded soil. A gap-graded soil shows a plateau (flat section) in the curve where particles of certain sizes are missing. The D10, D30, and D60 values are read directly from the curve by interpolation between the plotted points.

[FIGURE — Semi-logarithmic gradation curve showing percent passing vs particle diameter with D10, D30, D60 annotations and well-graded vs poorly-graded comparison]

Practical Engineering Notes

Note:

Wet sieving is mandatory for soils with more than 5–10% clay or plastic fines. During dry sieving, clay particles tend to coat sand and gravel particles, causing them to be retained on larger sieves than their size warrants. This shifts the gradation curve to the right (coarser than actual). The wet sieving procedure washes the fines through the No. 200 sieve using a dispersing agent (sodium hexametaphosphate), removing adherent fines from coarse particles and producing an accurate separation.

Field Tip:

For rapid field assessment of gradation, hand-sieving with 3–4 critical sieves (3/4-inch, No. 4, No. 40, No. 200) can provide a rough check of material compliance. However, for any formal classification or design, mechanical sieving following ASTM D6913 is required. The visual classification (ASTM D2488) should be used as a field check but not as a substitute for laboratory gradation.

Warning:

The total mass after sieving should not differ from the initial dry mass by more than 1%. If the mass loss exceeds 1%, the test must be repeated because the missing material disproportionately affects the fines percentage. Mass loss typically occurs from fines being blown away during transfer or retained in the sieve mesh. Clean sieves carefully between tests using compressed air or ultrasonic cleaning to prevent blinding.

Typical Workflow

  1. Air-dry or oven-dry the soil sample at 110°C to constant mass. Weigh and record the total dry mass.
  2. Select sieve sizes to cover the expected particle size range (typically 3-inch down to No. 200, following the standard progression).
  3. For dry sieving: place the dried sample on the top sieve, cover, and shake for the standard duration (typically 10–15 minutes on a mechanical shaker).
  4. For wet sieving: wash the sample through the No. 200 sieve with tap water and a dispersing agent; dry the retained fraction and perform dry sieving on it.
  5. After shaking, carefully weigh the mass retained on each sieve and in the bottom pan. Record each mass.
  6. Calculate the percent retained on each sieve and the cumulative percent passing.
  7. Plot the gradation curve on semi-logarithmic paper (or using software with a logarithmic X-axis).
  8. Read D10, D30, and D60 from the curve by interpolation.
  9. Calculate CU and CC and classify the soil per ASTM D2487.

Common Mistakes

  • Overloading sieves — placing too much material on a sieve prevents individual particles from reaching the openings. Maximum retained mass per sieve should not exceed the sieve area divided by the opening size in mm (e.g., ~200 g for 200 mm diameter No. 200 sieve).
  • Insufficient shaking time — incomplete sieving leaves material on larger sieves, shifting the curve to the coarser side. Verify endpoint shaking by checking that less than 1% of the mass passes during an additional minute of shaking.
  • Using dry sieving for plastic soils — clay coatings on sand particles cause significant errors. Always use wet sieving for soils with plastic fines.
  • Mass loss exceeding 1% — lost fines disproportionately affect the percent passing No. 200, which is the critical classification criterion.
  • Incorrect interpolation for D-values — D10, D30, and D60 are read from the curve on a log scale; linear interpolation between sieve sizes on a log-probability chart is required, not arithmetic interpolation.
  • Blinding of No. 200 sieve — sieve openings become clogged with fines; use wet sieving or clean the sieve thoroughly between tests.

Best Practices

  • Standardize the sieve stack configuration for routine testing to ensure consistency across projects.
  • Calibrate the mechanical shaker annually — vibration frequency and amplitude affect sieving efficiency.
  • Use ASTM E11 calibrated sieves with certified opening sizes. Replace sieves that have stretched or damaged mesh.
  • For critical projects, perform duplicate analyses on split samples and report the average gradation.
  • Include a hydrometer analysis (ASTM D7928) when the percent passing No. 200 exceeds 5–10% to characterize the silt and clay fractions.
  • Store sieves in a dry environment and inspect the mesh under a magnifying lamp before each use.

Limitations

  • Cannot determine particle shape or angularity — only particle size as defined by sieve openings (a particle passes if its smallest cross-section is smaller than the opening).
  • Does not characterize particles smaller than 75 μm — a hydrometer or sedimentation analysis is required for the silt and clay fractions.
  • Dry sieving of soils with plastic fines produces unreliable results — wet sieving adds time and complexity.
  • Fibrous organic soils, coal, and other non-mineral materials are not suitable for sieve analysis.
  • Results are influenced by the sieving method and duration — inter-laboratory variability of ±5% on key sieves is typical.

Related CivilFlow Calculators

Related Formulas

See the Geotechnical Formulas section for particle-size distribution calculations, uniformity coefficient, and curvature coefficient formulas.

Related Handbook Chapters

Refer to the Engineering Handbook for soil classification, filter design, and pavement material selection guidance.

Related Blog Articles

Related Learn Pages

Explore the Geotechnical Engineering learn page for soil classification and index properties.

Related Glossary Terms

Visit the Glossary for definitions of gradation, D10, uniformity coefficient, coefficient of curvature, and related particle-size terms.

References

  • ASTM D6913-17, "Standard Test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve Analysis," ASTM International, 2017.
  • ASTM D2487-17, "Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System)," ASTM International, 2017.
  • ASTM E11-20, "Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves," ASTM International, 2020.
  • ASTM D7928-21, "Standard Test Method for Particle-Size Distribution (Gradation) of Fine-Grained Soils Using the Sedimentation (Hydrometer) Analysis," ASTM International, 2021.
  • Holtz, R.D., Kovacs, W.D., and Sheahan, T.C., "An Introduction to Geotechnical Engineering," 2nd Ed., Pearson, 2011.