Effect of coarse aggregate mineralogy on micro-texture deterioration and polished stone value.

• Igneous aggregates, mainly granites, showed high PSV and good polishing resistance. • Granite aggregates with altered minerals witnessed poor polishing resistance. • RHD, DH, and DA influence micro-texture deterioration rate (BPN3-BPN6). • PSV showed a good correlation with RHD and DH. • Fundamental mineralogical parameters can better predict BPN3-BPN6 than PSV. The objective of the study presented in the paper is to identify the mineralogical parameters that influence both micro-texture deterioration and Polished Stone Value (PSV), which are the two most important properties of the aggregates that control the pavement skid resistance. The study was carried out on fourteen sources of aggregates which belong to either igneous or metamorphic rock category, the two most commonly used aggregate categories for surface course mixtures in India. PSV of aggregates was determined as per BS EN 1097-8: 2009. To investigate the progressive extent of polishing, the British Pendulum Number (BPN) of the aggregate was determined after every hour of polishing. Simultaneously, the mineralogical parameters were also obtained based on the microscopic observations of the thin sections of the aggregates. From accelerated polishing tests, it was observed that igneous aggregates, especially granites, were found to have relatively high PSV and good polishing resistance. Nevertheless, granite aggregates with altered minerals witnessed poor polishing resistance. Correlation analysis on the combined data for igneous and metamorphic aggregates suggested that the mineralogical parameters such as Relative Hardness (RHD) of aggregates, Differential Hardness (DH) between major minerals within the aggregate, and degree of alteration (DA) influence micro-texture deterioration rate (BPN3-BPN6). PSV showed a good correlation with RHD and DH. It was also noted that altered granite aggregates of igneous type significantly influenced the correlation. In general, it was observed that fundamental mineralogical parameters can better predict BPN3-BPN6 than PSV. [ABSTRACT FROM AUTHOR]