FUNDAMENTAL-STUDY ON THE EVALUATION OF STRENGTH OF GRANULAR PARTICLES

Compaction mechanisms and the strength required for compacting granula r particles are considered to be influenced by granular particle stren gth. A fundamental study evaluating the crushing strength of particles by various methods was performed, and value obtained by the various m ethods were compared. Firstly, the particle diameter and crushing load for 140 particles were measured individually, and the single particle strength (sigma(g)) was calculated. The crushing strength exponential ly decreased with an increase in particle diameter up to about 500 mu m, and thereafter showed a constant value. Next, the compression of mu ltiple particles was measured. A linear relationship existed between t he crushing load and the number of particles, and the average particle strength (<(sigma)over bar>(g)) was found to be lower than sigma(g) i n every sample. This may be due to a variety of factors such as the di stribution of particle diameter, shape, and crushing strength in multi ple particles. Finally, compaction tests of the particle bed were perf ormed, and the parameters of some compression equations, which were re cognized as values related to the particle strength were determined. T he inflection points of the compression curve were also examined. The strength obtained from the first inflection point appeared to be in fa irly good agreement with <(sigma)over bar>(g).