About Sieve Analysis

This guide provides a detailed breakdown of the Granule Size Distribution (Sieve Analysis) calculator, a fundamental tool in geotechnical engineering and materials testing. Sieve analysis is a standardized procedure used to determine the particle size distribution of a granular material, such as soil or aggregate, by passing it through a series of sieves with progressively smaller mesh openings.

What This Calculator Does

The calculator automates the entire sieve analysis calculation process. By inputting the total sample mass and the mass of material retained on each sieve, it performs the following functions:

• Calculates the percentage of material passing through each sieve.
• Generates a particle size distribution curve, a key visual representation of the soil's gradation.
• Determines important particle diameters (D10, D30, D50, D60) through logarithmic interpolation.
• Computes the Coefficient of Uniformity (Cu) and the Coefficient of Curvature (Cc) to quantify the gradation.
• Provides a preliminary soil classification for coarse-grained soils based on the Unified Soil Classification System (USCS).
• Verifies data integrity by calculating the percentage of mass loss during the sieving process.

When to Use It

Sieve analysis is critical in various civil engineering and construction applications:

• Geotechnical Investigations: To classify soils for foundation design, slope stability analysis, and earthwork specifications.
• Construction Materials Testing: To ensure aggregates for concrete and asphalt meet project specifications for strength and durability.
• Pavement Design: To design stable and well-draining base and sub-base layers for roads and airfields.
• Environmental Engineering: To assess soil for filtration systems and landfill liners.

Inputs Explained

Results Explained

Formula / Method

The calculator employs standard geotechnical formulas to process the data:

• Percent Retained: (% Retained) = (Mass Retained / Total Dry Mass) * 100
• Cumulative Percent Retained: The sum of the Percent Retained for the current sieve and all sieves with larger openings.
• Percent Passing: (% Passing) = 100 - (Cumulative % Retained)
• Coefficient of Uniformity (Cu): Cu = D60 / D10
• Coefficient of Curvature (Cc): Cc = (D30)^2 / (D10 * D60)

The D-values (D10, D30, D60) are determined by logarithmic interpolation between the two sieve sizes that bracket the target percentage passing.

Step-by-Step Example

Consider a sample with a Total Dry Mass of 500.0 g. After sieving, the following masses are retained:

1. Calculations: The table shows the step-by-step calculation of percent retained and passing for each sieve.
2. Find D-values: From the curve or by interpolation, we find D60 (at 60% passing), D30 (at 30% passing), and D10 (at 10% passing). In this example, D30 is exactly 0.425 mm. D60 would be between 2.00 mm and 0.425 mm. D10 would be between 0.425 mm and 0.075 mm.
3. Calculate Coefficients: Using the interpolated D-values, we calculate Cu and Cc.
4. Classify:
   • % Gravel: 5.0%
   • % Fines: 6.0% (Amount passing No. 200 sieve)
   • % Sand: 100% - 5.0% - 6.0% = 89.0%
   • Since the coarse fraction is mostly sand, and fines are between 5% and 12%, this is a borderline case like SW-SM or SP-SM, pending Cu and Cc values.

Tips + Common Errors

• Ensure Sample is Dry: The initial mass must be from a completely oven-dried sample. Moisture will lead to inaccurate results.
• Check for Overloading: Do not overload the sieves. This can cause inaccurate separation and potentially damage the sieve mesh. Follow ASTM guidelines for maximum mass per sieve size.
• Verify Mass Loss: A significant mass loss (>2%) suggests procedural errors, such as losing material during transfer or having a faulty scale. A mass gain indicates a scale error or moisture absorption.
• Clean Sieves Thoroughly: Ensure all sieves are clean before use. Particles trapped from previous tests will contaminate the results.
• Understand Limitations: This analysis is for the coarse fraction of soil. For fine-grained soils (silt and clay), a hydrometer analysis is necessary to determine the particle size distribution.

Frequently Asked Questions (FAQs)

What is the purpose of a sieve analysis?

Its primary purpose is to determine the gradation (particle size distribution) of a soil. This information is crucial for classifying the soil and predicting its engineering properties, such as strength, permeability, and susceptibility to frost.

Why is my calculated mass loss high?

A high mass loss (typically over 2%) can be caused by several factors: spillage during the transfer of the sample, fine dust becoming airborne and lost during sieving, or errors in weighing. It's a key indicator that the test results may be unreliable and should be repeated.

What do the Cu and Cc values signify?

Cu (Coefficient of Uniformity) measures the range of particle sizes. A high Cu means a wide range of sizes (well-graded), while a low Cu means the particles are mostly one size (poorly-graded or uniform). Cc (Coefficient of Curvature) describes the shape of the gradation curve. A Cc between 1 and 3 indicates a smooth, continuous curve, which is a requirement for well-graded soils.

The calculator classified my soil as "Fine-grained". What's next?

When more than 50% of the material passes the No. 200 sieve (0.075 mm), the soil is fine-grained. Sieve analysis is not sufficient for these soils. You must perform Atterberg Limits tests (Liquid Limit and Plastic Limit) to determine the soil's plasticity and classify it as silt (M) or clay (C).

What is the difference between a well-graded (GW, SW) and poorly-graded (GP, SP) soil?

A well-graded soil has a good representation of all particle sizes, which allows smaller particles to fill the voids between larger ones, leading to a dense, strong soil mass. A poorly-graded soil consists of either particles of all the same size (uniform) or is missing certain sizes (gap-graded).

How does the calculator determine the D-values (D10, D60)?

Since the target percentages (10%, 60%, etc.) rarely fall exactly on a sieve size, the calculator uses logarithmic interpolation. It uses the percent passing data from the sieves immediately above and below the target percentage to calculate a precise particle diameter on a log scale, which is standard practice.

Can I enter the sieves in any order in the calculator?

Yes. The calculator's logic automatically sorts the entered sieve data from the largest opening to the smallest before performing any calculations, ensuring the correct cumulative analysis.

Why is the mass collected in the pan important?

The pan collects all particles finer than the smallest sieve (usually the No. 200 / 0.075 mm sieve). This mass represents the total percentage of fines (silt and clay) in the sample, which is a critical parameter for soil classification and behavior.

References

• ASTM International. (2017). ASTM D6913/D6913M-17, Standard Test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve Analysis. ASTM International. https://www.astm.org/d6913_d6913m-17.html
• ASTM International. (2017). ASTM D2487-17, Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System). ASTM International. https://www.astm.org/d2487-17.html
• Das, B. M., & Sobhan, K. (2018). Principles of Geotechnical Engineering (9th ed.). Cengage Learning.
• U.S. Army Corps of Engineers. (1986). Engineering and Design - Laboratory Soils Testing (EM 1110-2-1906). Washington, D.C.

Disclaimer

This tool is for informational and educational purposes only. It should not be used as a substitute for professional engineering design, analysis, or judgment. All calculations should be verified by a qualified professional before being used for any real-world application. The developers assume no responsibility for any actions taken based on the results of this calculator.