Visual Aggregate Testing Samples

PTS Ltd can perform particle size distribution – sieving method in compliance with BS EN 933-1:2012. This is the most basic of tests which can be used for mix design and quality control. We calibrate all our own sieves in-house and carry out regular audits to ensure our quality remains to the highest standards.

Polished Stone Value testing is another test we have expertise in and PTS Ltd are one of only a handful of test laboratories offering the full service. So, whether it's new aggregate to check the PSV of or established aggregate in for an annual test we can cover your needs. The aggregate test is performed in accordance with BS EN 1097-8:2009.

The Polished Stone Value test determines how quickly a sample of aggregate will become polished or worn smooth by the repeated passing of tyres. The road surface layer needs to retain its rough texture to provide skid resistance for traffic. The higher the polished stone value, the longer the aggregate will hold its resistant texture in road surfacing.

Our PSV equipment includes an accelerated polishing machine, which is designed to imitate the effect of tyres on a road, as well as apparatus to test the friction. Samples of aggregate are fixed into small moulds using resin, according to a specified method, together with a control sample of known PSV. Each sample is then subjected to polishing in the accelerated polishing machine, in the prescribed order.

After polishing, the friction test is carried out first on the control samples to calibrate the apparatus and then on each test sample in turn. PSV results are expressed as categories such as PSV68, PSV62 or PSV56 with the number representing the minimum value for the aggregate. For road surfacing in critical locations a value of at least 62 is often required.

If you have any queries or requests for tests in this field, then contact the lab and we will be happy to help.

Sifting concrete, part of the aggregate testing process