Drying model of a high salt content cementitious waste form: Effect of capillary forces and salt solution

• Published in: Cement and concrete research Vol. 146; no. C; p. 106459
• Main Authors: Zhang, Peng, Chen, Zhiliang, Brown, Kevin G., Meeussen, Johannes C.L., Gruber, Chen, Garrabrants, Andrew C., Kosson, David S.
• Format: Journal Article
• Language: English
• Published: Elmsford Elsevier Ltd 01.08.2021; Elsevier BV; Elsevier
• Subjects: Alkali activated cement; Capillary flow; Computational fluid dynamics; Drying; Efflorescence; Humidity; Liquid flow; Liquid-vapor equilibrium; Modeling; Pore size distribution; Pore solution; Relative humidity; Saline solutions; Salinity; Saturation; Speciation; Surface tension; Transport property; Transport property; Pore solution; Alkali activated cement; Modeling; Drying
• ISSN: 0008-8846; 1873-3948
• DOI: 10.1016/j.cemconres.2021.106459

A water transport model coupling capillary liquid flow with vapor diffusion is developed to describe the drying process for a cementitious waste form with high salinity porewater. Vapor-liquid equilibrium is formulated as the driving force for vapor diffusion and the model accounts for pore capillary and high salinity effects on water thermodynamic activity. Pore filling and porewater surface tension as a function of pore size distribution and water saturation have been quantified for the material. Geochemical speciation modeling is used to simulate porewater activity as a function of composition over the range of saturation. The theoretical relationship between relative humidity and water saturation generally agrees with experimental measurement, and the developed model is capable of predicting drying rates under various external relative humidity conditions. The model was developed to be incorporated into reactive transport models considering the effects of drying such as salt redistribution and efflorescence. •Drying model for a high salt content cementitious waste form is developed.•Water vapor diffusion and capillary liquid flow are distinguished.•Capillary and salt solution effects are considered in vapor-liquid equilibrium.