A better understanding of the material behaviour of prepared cane and bagasse during the crushing process, coupled with a milling model incorporating a material model that can reproduce that behaviour, is seen as the most promising avenue to make improvements to the crushing process. Improvements could be made, for example, in throughput, sugar extraction, and bagasse moisture. Previous work on prepared cane and bagasse at the pressures and compactions present at the pressure feeder has measured critical state behaviour similar to that displayed by soils. Magnitudes of material parameters have been derived. It was shown that material models being used for mill modelling could not with a single set of parameter values successfully model all the loading and unloading conditions relevant to milling. Several important deficiencies were identified. In order to check that the measured material behaviour applies at the much higher pressures and compactions present at the delivery nip of a mill, and determine the magnitudes of the material parameters which are required for computer modelling of an Australian six-roll mill, a set of direct shear tests have been carried out. This paper shows that bagasse displays critical state behaviour at the much higher
compactions, that the detail of the behaviour is different, and provides magnitudes of material parameters. The combined experimental results and previously identified model limitations are used to address the next stage in the development of a model that can properly reproduce the behaviour of the bagasse fibre. The features that are desirable in a material model in order to be able to reproduce bagasse behaviour are presented. A material model is presented which includes those features. Predictions from the model are compared with experimental measurements and improved performance is shown.