Automatic Classification of the Shape of Reclaimed Asphalt Granulates

Reclaimed asphalt pavement or RAP is a valuable resource in the manufacturing of sustainable asphalt mixtures. The size and shape of the RAP granules have a major impact on the structural integrity of the finished product, making it crucial to characterize these properties precisely. Existing methods of acquiring the granules’ properties are often expensive, time-consuming, and prone to subjective interpretations. Our goal is to devise an innovative approach that calculates and presents certain morphological properties of a batch of RAP granules. This paper describes a method that utilizes a cost-effective camera setup together with image processing algorithms implemented in MATLAB. The algorithms process the images to accurately determine the size, angularity, and flat and elongated ratio of the granulate. It was demonstrated on a lab scale with a limited number of experiments that it is possible to describe the three characteristics of RAP with the proposed algorithms.