A granulation procedure is described for preparing model binderless granules from spherical polystyrene colloids. The deformation and breakage behaviour of the granules was also studied. Impact and slow diametrical compression experiments were used to simulate the mechanical response of the granules at high and low strain rates, respectively. They were found to deform elasto-plastically before fracturing in a semi-brittle manner. Densification or rearrangement of particle packing in the deformed region was concluded to be the main mechanism for energy dissipation under both impact and diametrical compression. In addition, the surface chemistry of the constituent particles within the granules was found to be one of the factors that govern the strength. (c) 2005 Elsevier Ltd. All rights reserved.