Characterisation of liquid transfer processes and water adsorption mechanism on a porous ceramic by acoustic emission means

In this paper, some applications of acoustic emission (AE) technique to characterise the liquid transfer mechanisms during drying process of a porous ceramic are presented and discussed. Results are compared with the general theory of drying and a more recent approach dealing with thermodynamic modelling itself based on capillary stresses and hygromechanical coupling. The sensitivity of the acoustic emission technique to the energy release processes acting during liquid transfer in a porous material (sorption and desorption) has been emphasised and the hysteretic phenomenon in a porous ceramic has been illustrated. Based on the experiments, the relationship between the AE characteristics recorded during the tests and the different mechanisms, which take place during drying process, was underlined. Information deduced from AE measurements associated with other data obtained from weight-loss measurements enable to propose a qualitative description of drying chronology.