Measurement and modeling of water sorption isotherm for salt‐laden autoclaved aerated concrete

The authors reported on the measurement of water sorption isotherms for autoclaved aerated concrete, commonly called “autoclaved lightweight concrete” in Japan, containing aqueous salt (sodium chloride or magnesium chloride) solutions in concentrations ranging from low to saturated with precipitated salt in the material. The important parameters of the salt‐laden porous materials were clearly defined. The measurement results confirmed the significant impacts of salt on the sorption isotherms, particularly at high salt concentrations. The measured sorption isotherms were modeled with the existing model that considers the vapor pressure depression and the density of the salt solution. The results showed that the differences between the measurements and the model increased with increasing amount of precipitated salt in the material. Therefore, a modified model for predicting the water sorption isotherm for a porous material containing not only a salt solution but also precipitated salt was proposed and discussed. The modified model showed better agreement with the measurements.