This project developed and tested an automated image analysis system for measuring aggregate shape characteristics (Fig. 1). The work involved development of a software and a hardware system. The software incorporated several image analysis procedures and its application to measure the texture of a wide range of fine and coarse aggregates. The hardware for the image analysis system incorporated a computer-controlled mechanism to allow capturing different projections of aggregate particles and describing their shape properties rapidly and accurately. Further software refinement produced a user-friendly version of the original software that facilitated data presentation and manipulation. The hardware and software were then integrated to produce a prototype of the automated aggregate analysis system. The system was tested on a range of fine and coarse aggregates and the results were compared with hot mix asphalt performance data. The image analysis procedure provided detailed information on shape properties of aggregates in a relatively short time. The shape measurements also showed a good correlation with the resistance of asphalt mixes to permanent deformation measured in the laboratory using different wheel tracking devices. The FHWA plans to use this device is its mobile laboratory for demonstration and training. The International Center for Aggregate Research (ICAR) is also using this device in several of its studies.  The final report is available from the National Technical Information Service (NTIS # PB2003-102870).

The final report for this IDEA project can be found at:
https://onlinepubs.trb.org/onlinepubs/archive/studies/idea/finalreports/highway/NCHRP077_Final_Report.pdf