ABSTRACT
The complexity of a transport model for porous building materials increases considerably, if not only heat, air and moisture, but also salt transport and phase change processes are considered. The system state must be described not only by air pressure, temperature and water content, but also by the concentrations of the different salt species in dissolved and crystallised phase. This leads to additional differential equations describing these new quantities and to new transport processes with salt diffusion coefficients or coefficients describing the crystallisation dynamics. It will be shown, which state variables must be chosen to describe the transport processes as easy as possible. Also changes occur at nonzero salt concentrations of the well-known equilibrium relationships such as the capillary pressure equilibrium (the moisture retention function) and the evaporation equilibrium (the Kelvin relationship). An overview will be given over the current state of the transport model. A nomenclature will be introduced describing all the different transport processes in a consistent and comprehensive fashion.
