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International Use of the PSV Test
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This British Standard has been adopted and used widely throughout the world. It is the only test with available equipment to calculate Polished Stone Values. The Permanent International Association of Road Congresses PIARC in conjunction with RILEM and the American Society for Testing Materials (ASTM), recommend the use of BS 812 to determine Polish Stone Values.

The PSV Test
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Full details are given in BS812Part1 14:1989. A copy of this document is essential to understand and carry out the test.

Four curved test specimens are prepared from each sample undergoing test. Each consists of 35 to 50 representative chippings of carefully controlled size supported in a rigid matrix.


Fourteen specimens are clamped around the periphery of the 'road wheel' and subjected to two phases of polishing by wheels with rubber tyres. The first phase is of abrasion by corn emery for three hours, followed by three hours of polishing with emery flour. Two of the fourteen samples are of Control stone.


The degree of polish of the specimens is then measured by means of the Portable Skid Resistance Tester (using a special narrow slider, shorter test length and supplementary scale) under carefully controlled conditions. Control specimens are used to condition and check the slider before the test.  Also a pair of control specimens is included in each test run of fourteen specimens to check the entire procedure and to allow for adjustment of the result to compensate for minor variations in the polishing and or friction testing. Results are expressed as 'Polished Stone Values' (PSVs), the mean of the four test specimens of each aggregate.