Quantification of aggregate morphologic characteristics with the correlation to uncompacted void content of coarse aggregates in Virginia

A three-dimensional (3-D) high-resolution image analysis system for aggregate morphologies characterization, the Improved Fourier Transform Interferometry (FTI) system, is presented. The following aggregate morphological characteristics were measured: sphericity, flatness ratio, elongation ratio, angularity and surface texture. Compared to the FTI system, the improved FTI system improves usability and data collection speed and provides a more user-friendly graphical interface. The objective of this paper is to investigate the correlation between morphological characteristics and uncompacted void content of coarse aggregates. Sixteen types of coarse aggregates from different quarries in Virginia were analyzed using the improved FTI system. It was found that aggregates' morphological characteristics can be affected by the material type, size, origin and crushing technique. The shape results from the improved FTI system showed a good agreement with the manual measurements via a caliper, demonstrating the accuracy of this image analysis system. The relationship between the void contents of different sizes of coarse aggregates and morphological characteristics was examined. Regression analysis indicated that void content was significantly influenced by the morphological characteristics.