Heat and Moisture Transport in Porous Building Materials Containing Salt

摘要

The durability of most porous building materials is strongly related with moisture and salt transport mechanisms. They are closely related with inner structure of a material. Therefore, influence of salt on porous structure of cement mortar, initially saturated with different solutions of NaCl, was analysed. SEM and MIP tests were performed and changes of pores size distribution, internal surface and mean pore diameter with the amount of accumulated salt are presented. By thermodynamic balance the dissolution/precipitation process is described using adsorption isotherm. Based on experimental data and theoretical derivations a novel mathematical model describing coupled heat, moisture and salt transport is formulated. The computer code based on it was developed and verified against some available experimental data. Using the software the influence of salt (osmosis, precipitation, sorption isotherm) on moisture content in cementitious building material is analysed.