Unified Imaging Approach for Measuring Aggregate Angularity and Texture

Abstract

The effect of fine aggregate morphologic properties on asphalt mixtures' behavior is well recognized. However, the current procedures for measuring fine aggregate properties are at best indirect indicators of these properties. The indirect nature of the current measurements has led to inconsistency in predicting the extent to which the measured properties influence pavement performance. Two independent methods that integrate several aspects of image-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 operations. The second technique uses the change of an object perimeter with its shape. The analysis shows that the two methods are able to capture aggregate shape at two different scales. Angularity is captured using low-resolution images, whereas surface texture is captured using highresolution images. The presented image-analysis techniques have potential benefit in quantifying the effects of texture and angularity on asphalt pavement performance.

Fluidez de morteros cementíceos con arenas machacadas

“…Existen otros métodos con un grado mayor de sofisticación que emplean tomografía computada, microscopio electrónico de barrido, láser, procesamiento de imáge-nes, redes neuronales, fractales, o midiendo la resistencia al corte, etc., los que pueden resultar adecuados para trabajos de laboratorio pero son complejos para aplicar en obras (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). En general, el empleo de estos méto-dos se ve dificultado porque los mismos no han sido correlacionados con los métodos normalizados.…”

“…Other more sophisticated methods that use computerized tomography, scanning electron microscopy, laser techniques, imaging, neuronal networks, fractals, and shear strength measurements may prove to be suitable for laboratory trials but are too complex for field work (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). As a rule, the use of such methods encounters obstacles because they have not been correlated to standardized methods.…”

Portable Image Analysis System for Characterizing Aggregate Morphology

“…The computer program developed for this study is a good practical implementation of Fourier analysis method (Masad and Button 2000;Wettimuny and Penumadu 2004;Wang et al 2005) to quantify the shape, angularity, and surface texture of aggregates. The developed methodology is not tied to a specific device but is transferable to other integrated computer-camera devices or to systems incorporating individual computer (with Matlab) and camera components.…”

Relationships between Shape Characteristics and Shear Strength of Sands

“…The eŠect of particle shape on the properties of soils was discussed by several investigators (Koerner, 1970;Holubec and D'Appolonia, 1973;Kezdi, 1974;Ng, 1999). A Fourier analysis is a very useful method for quantifying particle shape and texture (Meloy, 1977;Masad and Button, 2000). While Barret's study (1980) separated the parameters deˆning the roughness of rocks as form factors, roundness, and roughness, Bowman et al (2001) deˆned particle roughness using a descriptive number.…”

“…In geotechnical engineering, image processing methods are very often used for the shape characterization of cohesionless soils. The advantages of using digital image processing techniques for shape identiˆcation have been emphasized by many researchers (Persson, 1999 Masad and Button, 2000). Evaluating the shape of sand grains can be helpful in determining several of the properties of soils such as index properties, the shearing behavior, and densiˆcation under a certain compactive eŠort.…”