Sieve Analysis
Particle Size Analysis (Sieving)
Enter the sieve opening and retained mass data to calculate the particle size distribution curve and coefficients.
What is Sieve Analysis?
Sieve analysis, also known as gradation analysis, is one of the most important geotechnical tests for characterizing soils, aggregates, and other particulate materials. In simple terms, it is the process of determining the distribution of different particle sizes that make up a sample. The result is fundamental for predicting the mechanical and hydraulic behavior of the material. [1]
Imagine a sample of sand. It is not made of grains of a single size, but rather a mixture of particles ranging from fine to coarse. Sieve analysis allows us to quantify this distribution, revealing the percentage of each particle size 'class' (such as clay, silt, fine sand, coarse sand, gravel, etc.) in the total sample. [1]
How to Use This Tool
Follow these simple steps to perform your online sieve analysis:
Access the Calculator
Navigate to the 'Analysis' tab in the side menu to view the data entry table.
Enter the Data
Fill in the 'Opening (mm)' columns with the diameters of your sieves and 'Mass Retained (g)' with the weight of the material retained on each one.
Add More Sieves
If you need more rows for your sieves, just click the 'New Row' button. To load an example dataset, use the 'Example' button.
Calculate the Results
With the data entered, click the green 'Analyze' button. The system will automatically calculate all the percentages, coefficients (Cu, Cc), and characteristic diameters (D10, D30, D60).
View the Graph
Scroll down the page to see the interactive Particle Size Distribution Curve. Hover over the points to see the exact values.
Generate the Report
For a formal record, click 'Generate Report'. Give your document a title, and a professional PDF with tables and the graph will be generated.
Why is Sieve Analysis So Important?
The particle size distribution directly influences crucial properties of the material, impacting various fields:
Civil Engineering
Essential for concrete mix design, selection of materials for pavement bases, and for the construction of dams and embankments. A well-graded material tends to be denser and stronger. [2]
Geology and Agronomy
Helps to classify soils, understand their genesis, and determine their agricultural suitability. The soil texture affects aeration, water retention capacity, and nutrient availability. [1]
Industry
Used in the quality control of products such as cement, ceramics, and pharmaceuticals, where particle size affects reactivity, dissolution, and the texture of the final product.
Main Methods of Analysis
The determination of the particle size distribution is generally carried out by two main methods, which can be used in combination:
1. Sieving
This is the most common method. The dry sample is passed through a series of sieves with progressively smaller mesh openings. By shaking the set, the particles are separated by size. The mass of material retained on each sieve is then weighed to determine the corresponding percentage. [1]
This method is effective for particles larger than 0.075 mm (sands and gravels).
2. Sedimentation
For fine particles (silts and clays), sieving is not practical. The sedimentation method is based on Stokes' Law, which relates the settling velocity of a particle in a fluid to its diameter. The change in the suspension's density over time is measured, allowing the calculation of the percentage of each particle size. [1]
Ideal for particles smaller than 0.075 mm.
Applications in Water Treatment
Particle size analysis is a fundamental parameter in the design and operation of water treatment plants (WTPs), especially in filtration processes, where efficiency depends directly on the filter media.
Filter Design (Sand and Anthracite)
The particle size distribution of the filter media (sand, anthracite) is crucial for the removal of impurities. The 'effective size' (D10) and the 'uniformity coefficient' (Cu) are defined by technical standards to ensure the quality of the treated water and an adequate filter run length. [3]
Selection of Support Layers (Gravel)
The gravel layers that support the sand bed are sized by gradation to allow water to pass through and prevent the loss of sand during backwashing. [3]
Backwash Efficiency
Filter media with improper gradation can lead to incorrect fluidization during backwashing, resulting in inefficient cleaning, loss of material, or the formation of 'preferential paths'.
Interpreting the Particle Size Distribution Curve
The final result of the analysis is expressed graphically by the **particle size distribution curve**. From it, the Coefficient of Uniformity (Cu) and the Coefficient of Curvature (Cc) are calculated, which help to classify the soil according to its gradation. [1]
The Y-axis (vertical) shows the percentage of material that passes through a given sieve.
The X-axis (horizontal), on a logarithmic scale, represents the particle diameters.
The slope of the curve reveals the nature of the soil:
- **Well-Graded:** A smooth curve extending over a wide range of diameters (typically Cu > 4 and 1 < Cc < 3 for sands).
- **Poorly-Graded (or Uniform):** A steep curve, concentrated in a narrow range of diameters.
- **Gap-Graded:** The curve has a plateau, indicating the absence of particles in a certain size range.
Example of Sieve Analysis Data Table
| Sieve (ASTM) | Opening (mm) | Mass Retained (g) | % Retained | Accum. % Retained | % Passing |
|---|---|---|---|---|---|
| No. 4 | 4.75 | 0.0 | 0.0% | 0.0% | 100.0% |
| No. 10 | 2.00 | 45.5 | 9.1% | 9.1% | 90.9% |
| No. 20 | 0.85 | 89.0 | 17.8% | 26.9% | 73.1% |
| No. 40 | 0.425 | 112.5 | 22.5% | 49.4% | 50.6% |
| No. 60 | 0.250 | 98.0 | 19.6% | 69.0% | 31.0% |
| No. 100 | 0.150 | 75.5 | 15.1% | 84.1% | 15.9% |
| No. 200 | 0.075 | 45.0 | 9.0% | 93.1% | 6.9% |
| Pan | - | 34.5 | 6.9% | 100.0% | 0.0% |
| Total Sample Mass: 500.0 g | |||||
Conclusion: An Indispensable Tool
Sieve analysis is much more than a simple laboratory procedure; it is a fundamental technique that provides vital information about the behavior of particulate materials. Whether ensuring the safety of an engineering project, optimizing an industrial process, or understanding the dynamics of an ecosystem, particle size analysis is the basis for well-informed technical decisions.
Technical References
- DAS, Braja M.; SOBHAN, Khaled. **Principles of Geotechnical Engineering**. 9th ed. Cengage Learning, 2018.
- NEVILLE, A. M. **Properties of Concrete**. 5th ed. Pearson, 2011.
- BRAZILIAN ASSOCIATION OF TECHNICAL STANDARDS. **NBR 12216**: Design of a water treatment plant for public supply. Rio de Janeiro, 1992.