Quantifying the Complexity of Sand Particle Shape Using Current Digital Image Analysis Technology.

Sands used to construct the root zones of athletic fields and golf course putting greens are subjected to several laboratory tests to evaluate their suitability prior to construction.  The test results are used to predict the performance of these materials in the field. The majority of the laboratory tests are quantitative and prospective root zones are evaluated objectively. However, sand particle shape (angularity and sphericity) is currently evaluated subjectively.   The objective of this research was to quantify differences in particle shape complexity of several sands utilizing current digital image analysis technology. Technology currently utilized by the pharmacutical and paint industries provides a testing procedure that is fast, reproducible, and applicable to current soil physical properties testing procedures practiced by American Association of Laboratory Accreditation (A2LA) accredited laboratories conducting root zone performance testing prior to construction. This technology uses two cameras under controlled light conditions to take 60 images per second of the particles as they fall randomly. These images are then analyzed and measured. Calculations are then completed to produce the parameters such as sphericity, aspect ratio, and symmetry. Five different sands ranging from well rounded to very angular were separated into the medium size class (0.25 – 0.50mm) to control variability introduced by particle size distribution   Glass beads were used as a rounded control and a product called BlackJack, commonly used in sand blasting applications, was used as a very angular control. Significant differences between all treatments were observed for sphericity, aspect ratio, and symmetry indicating that this technology provides a method to quantitatively assess particle shape complexity.