Quantifying Sand Particle Shape Complexity using a Dynamic, Digital Imaging Technique

Sands used to construct athletic fields and golf course putting greens arc characterized in laboratory tests to evaluate their suitability before construction. Many of these tests provide quantitative measurements of soil physical properties; however current evaluation procedures for particle shape rely on subjective visual assessments. The objective was to quantify differences in the particle shape complexity of sands using a dynamic, digital image analyzer, the Camsizer, and correlate those values to current quantitative and qualitative methods of particle shape analysis. The Camsizer uses two cameras to capture images of randomly falling particles at a rate of 60 frames s(-1). These images are analyzed and shape parameters such as sphericity and aspect ratio are calculated. Five monosize sands of varying shape were evaluated, as well as a rounded and angular control. The dynamic method showed significant differences between sphericity and aspect ratio values of all sands, indicating these parameters can be used to quantitatively assess particle shape complexity. The values obtained with the Camsizer and with a well accepted static, quantitative technique that uses light microscopy were correlated for both aspect ratio (r = 0.935) and sphericity (r = 0.982). The Camsizer values also exhibited a positive relationship with the qualitative shape parameters, sphericity, and angularity. The coefficient of variation values for the aspect ratio and sphericity data, as determined by the dynamic method, were significantly lower than the static method or the qualitative analysis. These results indicate that this digital imaging analysis tool provides an accurate, objective means of quantifying particle shape complexity.