Three-Dimensional Image Analysis of Aggregate Particles from Orthogonal Projections

Abstract

Digital image analysis provides the capability for rapid measurement of particle characteristics. When an image is captured and digitized, numerous measurements can be made in near real time for each particle. Usually, image analysis techniques treat particles as two-dimensional objects since only the two-dimensional projection of the particles is captured. In this study, three-dimensional analysis of aggregate particles that was performed by attaching aggregates in sample trays with two perpendicular faces is described. After the initial projected image of the aggregates is captured and measured, the sample trays are rotated 90 degrees so that the aggregates are now perpendicular to their original orientation and the dimensions of the aggregates in the new projected image are captured and measured. The long, intermediate, and short particle dimensions ( dL, dI, and dS, respectively) provide direct measures of the flatness and elongation of the particles. Some other shape indexes can also be derived from the measurements of area and perimeter length. The proposed image analysis method was verified by comparing the results obtained with manual measurements of particle dimensions for uniform size [passing 12.7 mm (1/2 in.) sieve and retained on 9.5 mm (3/8 in.) sieve] aggregates. Three-dimensional image analysis was also performed on five aggregates of standard size No. 89 from different sources, and the results are summarized herein. The proposed method is expected to improve field quality control of aggregates used in hot mix asphalt.

Geometrical model for tortuosity of transport paths in hardened cement pastes

“…The shape factor is a commonly used parameter describing the shape characteristics of cement particles and reflects the influences of the morphology of cement particles on tortuosity (Chen and Xu, 2003;Mora and Kwan, 2000), but different definitions for describing the shape characteristics of cement particles have been adopted (Barksdale et al, 1991;Chen and Xu, 2003;Kuo et al, 1996). In the present study, the shape factors ç c and ç r were derived from the sphericity ł c and cubic degree ł r , used to describe the degree of cement particle morphology approaching a sphere and cube respectively (Barksdale et al, 1991;Mora and Kwan, 2000;Taleb et al, 2007).…”

A simulation methodology for online process control of hot mix asphalt (HMA) production

“…Image analysis is a powerful computer-based method for gathering information of aggregate properties (Kuo et al 1996).…”

“…Kuo et al (1996) proposed a method to improve the accuracy of gradation estimation by image analysis in HMA production. However, their research is very limited to the size of the particles; fine particles cannot be easily detected (especially #200 sieve, the finest aggregates).…”

The relationship between the fractal dimension and shape properties of particles

“…In asphalt concrete, the shape of aggregate particles affects the durability, workability, shear resistance, tensile strength, stiffness, fatigue response, and optimum binder content of the mixture (Shklarsky and Livneh, 1964;Li and Kett, 1967;Stephens and Sinha, 1978;Kalcheff and Tunnicliff, 1982;Huber and Heiman, 1987;Krutz and Sebaaly, 1993;Kuo et al, 1996;Odurph et al, 2000;Masad et al, 2001;Topal and Sengoz, 2005;Al-Rousan et al, 2007;Arasan et al, 2010a). Since up to approximately 80 percent of the total volume of concrete consists of aggregate, aggregate characteristics significantly affect the performance of fresh and hardened concrete and have an impact on the cost effectiveness of concrete (Ozol, 1978;Hudson, 1999;Kwan et al, 1999;Erdogan, 2005;Erdogan et al, 2006;Jamkar and Rao, 2004).…”