Accelerated laboratory testing of aggregate friction properties

This paper presents a thorough analysis of an experimental method for measuring aggregate friction properties. The second-generation Aggregate Image Measurement System (AIMS) is used to measure coarse aggregate surface texture before and after polishing in a modified Micro-Deval (MD) test procedure, in addition to Variable Speed Friction Test (VST) samples. Investigating the relationships between AIMS-MD angularity and texture, a weak relationship was found between VST friction values and AIMS angularity after MD polishing for 105 min (AMD-105). Furthermore, the strong correlation between AIMS AMD-105 texture and the surface texture of VST friction samples indicated that MD is a viable option for replacing VST as a polishing mechanism. Finally, cluster analysis was conducted to obtain threshold for classifying aggregate angularity and texture into acceptable and non-acceptable zones (i.e., defining the criteria for qualifying aggregates for friction purposes).