Application of the acoustic emission technique to characterise liquid transfer in a porous ceramic during drying

In this paper, some aspects of the characterisation of liquid transfer during drying process of a porous ceramic by acoustic emission (AE) technique are presented and discussed. Results are compared with the general theory of drying and a recent approach dealing with thermodynamic modelling 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. 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. The results show that this new application of the AE technique could be considered as a valuable tool to study the liquid transfer in a porous material.