Unified imaging approach for measuring aggregate angularity and texture

The effect of fine aggregate morphologic properties on asphalt mixtures' be havior is well recognized. However the current procedures for measuring fin e aggregate properties are at best indirect indicators of these properties. The indirect nature of the current measurements has led to inconsistency i n predicting the extent to which the measured properties influence pavement performance. Two independent methods that integrate several aspects of ima ge-analysis techniques are presented for quantifying angularity and texture of fine aggregates. The first technique relies on the change of aggregate shape as it is subjected to a number of erosion-dilation morphologic operat ions. The second technique uses the change of an object perimeter with its shape. The analysis shows that the two methods are able to capture aggregat e shape at two different scales. Angularity is captured using low-resolutio n images, whereas surface texture is captured using high-resolution images. The presented image-analysis techniques have potential benefit in quantify ing the effects of texture and angularity on asphalt pavement performance.