Particle size distribution analysis

Particle size distribution shows the percentage of particles of different sizes in a soil — cobbles and gravel, sand, silt and clay. It is the primary parameter for naming a soil and gives a first indication of its permeability, compactability, frost susceptibility and strength.

Coarse-grained soils (gravel, sand) are analysed by sieving: a dry sample is passed through a nest of standard sieves and the mass retained on each sieve is weighed. In clayey and silty soils, particles finer than about 0.1 mm are measured by the hydrometer method, based on how quickly they settle in water. Mixed soils combine both methods.

Results are plotted as a grading curve, from which effective diameters (d10, d30, d60) and the coefficients of uniformity and curvature are calculated. These are used to classify sands, select drainage and filter materials, check the suitability of fill and pavement layers, and assess the liquefaction susceptibility of sands during earthquakes.

We test both natural soils and quarry sand-gravel mixes and aggregates in line with applicable standards (GOST, AzDTN) for clients in Baku and throughout Azerbaijan.

When you need it

• Identifying and naming the soil
• Checking materials for fill and pavement layers
• Selecting drainage and filter materials
• Assessing liquefaction susceptibility of sands
• Quality control of quarry materials

What's included

• Drying and preparing the sample
• Sieve analysis with a standard sieve set
• Hydrometer analysis of fines
• Plotting the grading curve
• Calculating d10, d30, d60 and the uniformity coefficient
• Naming the soil per standard classification

How we work

1. Sample receipt
2. Drying and preparation
3. Sieve and/or hydrometer analysis
4. Plotting and calculations
5. Issue of certificate

Deliverables

• Grading curve
• Table of fraction percentages
• Coefficients of uniformity and curvature
• Test certificate with soil name