Characterising bitumen binders for pavements in the Auckland region

The presented study was conducted to compare two binder selection processes, specifically, a penetration grading system and a performance grading system, to determine which system would provide the best predictor of field binder performance. Weather data for the Auckland region of New Zealand was analysed to determine pavement temperature variations within the region, and an assessment was made of the relevance of the proposed PG 64-16 binder grade for the Auckland region. The results revealed that the PG 64-16 binder grade was appropriate for the pavement temperature ranges present in Auckland. Additionally, laboratory testing was conducted on two commonly used binder samples, a 40/50 fully blown blend (Sample 1) and a 40/50 70% New Route (NR) blend, which is a butane precipitated blend (Sample 2), to compare the comprehensiveness of the penetration grading system and the performance grading system. The penetration grading tests graded both blends as 60/70. The performance grading tests graded Sample 1 as PG 64-16 H (high traffic) and Sample 2 as PG 64-16 S (standard traffic). The performance grading system was found to be more comprehensive than the penetration grading system, as it was able to differentiate between different traffic loading conditions. Hence, the performance grading system is recommended for binder selection in Auckland.