The objective of this project was to investigate the durability and mechanical integrity of aggregate with a high polished stone value (>60) used in hot mix asphalt, particularly chips or coarse aggregates in stone-on-stone mixes such as stone mastic asphalts and open graded porous asphalts. The research was carried out in Auckland, New Zealand, in 2009-2010.
Test sections were constructed within a roading contractor's yards at Auckland and Taupo. The aggregates used were drawn from four different sources. Significant degradation took place during laying and compaction, but trafficking produced little further breakdown, if any. However, a slight decrease in air voids and texture depth was apparent.
Most of the source property tests could not predict the degradation that occurred in the test sections. The Los Angeles and micro-deval abrasion tests were probably the most useful. The gyratory compactor test was also evaluated as a prediction tool without a great deal of success. The micro-deval abrasion test ranked the aggregates in a similar sequence to that achieved using the gyratory compactor test.