Abstract: Aggregate shape greatly affects the workability and mechanical properties of concrete. Nevertheless, the irregular shape of aggregate particle defies full definition and measurements. In this article, the particle shape and particle size of crushed limestone coarse aggregate were studied with Digital Image Processing (DIP) method, and the results were compared with the values measured by caliper gauge. Results revealed that the length, width and length-diameter ratio measured by the two methods were almost equal; but the thickness, flatness ratio, sphericity and the grain shape factor obtained by the DIP method varied remarkably. The value of λ was corrected, and the correction factor was 1.82. The deviation of the corrected results was less than 2%.

Key words: crushed coarse aggregate, digital image processing method, particle shape, flatness ratio, correction factor