Distances between air-voids in concrete by automatic methods

In order to access to the air-void distances in concrete by automatic image analysis, three different methods were proposed, used and discussed: half-distances between two voids nearest neighbours, called count-dilation; half-distances between all neighbours, called SKIZ; and distance function. They were utilized in a euclidean and geodesic way. Some of them can replace favourably the manual methods proposed in the different standards. (C) 2001 Elsevier Science Ltd. All rights reserved.