SUMMARYAggregates of a fine textured (61% clay, 33% silt) soil with a high coefficient of linear expansion (20%) were exposed to successive wet/dry cycles in their natural state and after mechanical reworking. In both cases aggregate size decreased; the reworked sample initially consisted of larger aggregates, but their size fell more rapidly, and after four cycles both the reworked and natural aggregates had a similar size distribution. A model was developed which successfully predicts the proportion of aggregates in each size grade at thenth cycle from that present at the outset. The rate of decrease in aggregates size declined with aggregate size and on both reworked and natural samples the dispersion ratio was low (≤5%