Determination of 3-D air void characteristics in hardened concrete by means of image analysis
Abstract
For concrete to have excellent frost durability it is effective to control the void distribution in the material. To rebuild the three-dimensional void distribution, there are only two methods that are described in a norm. Image analysis provides a powerful tool to ameliorate and fasten these methods. There has been considerable research activity at our institute in these areas over the last two years.
The existing methods, described in the norm ASTM C457-71, have been implemented on an automated image analysis system. It concerns the modified point counting and linear traverse techniques. Two-dimensional data resulting from simple plane sections measurements on hardened concrete specimens are worked out to reconstruct the three-dimensional void-distribution. Current thoughts and approaches are emphasized.