Title: Surface Textural Controls on High PSV Aggregates
Researchers: Dr Richard Unitt, Dr Pat Meere
This project will define the petrological characteristics of high PSV and very high PSV (polished stone value) aggregates from Carrigcleena Quarry, Mallow, County Cork. The quarry has been producing high PSV aggregates, mainly from volcanic rocks, since 1978. It has been recognised that focussed petrological studies are essential for the production and quality control of road construction materials.
The UK Highways Agency describes the highest grade of road aggregate as having a PSV of ≥68. This type of material is used to provide a skid resistance surface at high stress sites, such as junctions and roundabouts.
In July 2013 the NRA issued an Interim Advice Note IAN 05/13 in relation to Road Surfacing, Skidding Resistance and Selection of Aggregates. This has resulted in a substantial increase in demand for the highest grade PSV aggregates.
However, very high PSV aggregates are only produced at a limited number of sites in Ireland and the UK. In addition, the only source of pre-coated chips (essential for Hot Rolled Asphalt surfacing) on the Island is in Northern Ireland.
Carrigcleena Quarry has a long record of producing high PSV aggregates. In the last few years an area of the quarry with a sequence of sandstones and siltstones has been worked. Bulk test results from these rocks have recorded very high PSV values of (≥68) and individuals units have yielded PSV readings ≤ 66