Testing unbound aggregates and hydraulically bound mixtures

Delivered crushed rock materials, recycled aggregates, and drainage gravels are all produced to specification. Loads are sampled at regular intervals to confirm deliveries are in order and to enable laboratory testing for compliance.

Primarily the sieve analysis (grading) and the moisture content are confirmed as these have the most immediate effect on the works into which the material is to be incorporated.

Sieve Analysis

Sieve Analysis or Gradation of Aggregate test is the process of splitting a sample of unbound material into decreasing sizes to identify the range of particles and the material’s likely characteristics. Using a set of calibrated sieves, a graphical representation known as a Particle Size Distribution graph (PSD) can be made and used to classify an in-situ material or confirm compliance of a bought-in, processed material.

This test is an integral part of quality control regimes in civil engineering works. Grading analysis for classification purposes is carried out to BS 1377-2, and aggregate compliance is carried out to BS EN 933-1.

Soil Sieving in the Lab

Aggregate Testing Services

  • Particle Size Distribution
  • Water Content
  • Fines Content
  • Particle Density Water Absorption
  • Particle Density
  • Flakiness Index
  • Shape Index
  • LA Co-Efficient
  • Ten Percent Fines Value
  • Constituent Parts of Recycled Aggregate
  • Magnesium Sulphate Soundness
  • Micro Deval


The relevant UKAS accredited aggregate laboratory tests, and the corresponding standard numbers are:

Test Standard Number

Sampling from stockpiles

BS EN 932-1:1997

Sample reduction using a riffle Box

BS EN 932-2:1999

Sample reduction by quartering

BS EN 932-2:1999

Particle size distribution - sieving method

BS EN 933-1:2012

Flakiness index

BS EN 933-3:2012

Classification test for the constituents of coarse recycled aggregate

BS EN 933-11:2009

Resistance to fragmentation by the Los Angeles method –including Annex A – Railway Ballast

BS EN 1097-2:2020

Water content

BS EN 1097-5:2008

Particle density and water absorption - pyknometer method for aggregate particles between 4 mm and 31,5 mm

BS EN 1097-6: 2013

Particle density and water absorption - pyknometer method for aggregates between 0.063 mm and 4 mm

BS EN 1097-6: 2013

Magnesium Sulphate test

BS EN 1367-2:2009

Uniformity coefficient

BS EN 14688-2:2018

Below are the relevant UKAS accredited laboratory tests for Unbound and Hydraulically Bound Mixture Tests, and their corresponding standard numbers:

Unbound and Hydraulically Bound Mixtures
Test Standard Number

Laboratory reference density and water content - vibrating hammer

BS EN 13286-4:2003

California bearing ratio, immediate bearing index and linear swelling

BS EN 13286-47:2021

Manufacture of test specimens of hydraulically bound mixtures using vibrating hammer compaction

BS EN 13286-51:2004

Curing of hydraulically bound mixtures

BS EN 14227-1:2004

Frequently Asked Questions

What does a sieve analysis do?

A sieve analysis is a technique used to determine the particle size distribution of a granular material. It involves passing a sample through a series of sieves with progressively smaller openings to separate particles into different size fractions.

How do you interpret sieve results?

Interpreting sieve results involves analysing the distribution of particle sizes within a material based on the sieve analysis. This is typically presented as a cumulative percentage of material retained on each sieve. A steep curve indicates a well-graded material with a wide range of particle sizes, while a flatter curve suggests a more uniformly sized material. 

What is the minimum sample size for sieve analysis?

The minimum sample size for sieve analysis depends on the particle size distribution of the material being tested and the specifications of the analysis method. Simtec can advise you further. 

What is the British Standard for sieve analysis?

The British Standard sieve analysis is BS EN 933-1.

Is sieve analysis the same as a gradation of aggregate test?

Yes, sieve analysis and gradation of aggregate test refer to the same testing procedure.

What are the benefits of aggregate testing?

The main benefits of aggregate testing include complying with regulations, making informed decisions on aggregate usage, and quality control.