Image analysis method for determining 3-D size distribution of coarse aggregates

A new 3-D grain size distribution analysis method for coarse aggregates using image analysis is presented. The method is designed for a laboratory environment and requires no sieving, only imaging of the aggregate. A luminous background material eliminates unwanted shadow effects. Particles are placed so they are not touching, thus the images of the aggregates are of good quality allowing an easy and accurate image analysis with no pre-processing. All three axial lengths of every particle are measured. The results can be plotted either as a continuous curve or showing the axial size of each and every particle. The latter allows the frequency of particles in the tails to be easily evaluated. Good agreement exists between the size distribution curves obtained from the Image Analysis and hand measurements using the Danish Box.