Evaluation of the AIMS2 and Micro-Deval to Characterize Aggregate Friction Properties

This National Center for Asphalt Technology (NCAT) report is a summary of a study performed at NCAT by Auburn University Civil Engineering graduate student Mary Greer. Details of the study are reported in her Master's Thesis as part of her qualifications for a Master of Science Degree in May 2015. There is a need for a laboratory protocol to rapidly evaluate the quality of aggregate friction properties for use in an asphalt surface. Aggregates with good friction resist polishing and retain their shape characteristics. An asphalt surface needs to maintain adequate friction as it is polished by traffic to ensure motorists' safety on the roadway. Some current laboratory procedures used to evaluate the friction properties of aggregates are time consuming and subjective. The purpose of this research study was to evaluate the correlation of aggregate field friction performance to aggregate properties using a laboratory protocol consisting of the second generation Aggregate Imaging Measurement System Model AFA2A (AIMS2) and Micro-Deval. The test protocol used the AIMS2 device to quantify aggregate shape characteristics (angularity, texture, and form) before and after polishing in the Micro-Deval. The aggregates were selected for their friction performance in asphalt surfaces at the NCAT Test Track. Field friction performance was measured with the locked-wheel skid trailer. Aggregate angularity and texture indexes were compared with the skid trailer field measurements to determine if a correlation could be established. The AIMS2 device detected changes in aggregate shape after conditioning in the Micro-Deval. However, the analysis did not establish good correlation between the AIMS2 indexes and the field friction data using the test protocol developed in this research study. Additional studies are needed to expand the aggregate types and enhance the laboratory test protocol to verify these conclusions or improve the ability of the test to correlate to field friction performance.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; Photos; References; Tables;
  • Pagination: 64p

Subject/Index Terms

Filing Info

  • Accession Number: 01635102
  • Record Type: Publication
  • Report/Paper Numbers: NCAT Report 17-02
  • Files: TRIS, ATRI, USDOT
  • Created Date: Apr 26 2017 11:03AM