KAUST DepartmentEarth Science and Engineering Program
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AbstractThe salt concentration gradually increases at the soil free surface when the evaporation rate exceeds the diffusive counter transport. Eventually, salt precipitates and crystals form a porous sodium chloride crust with a porosity of 0.43 ± 0.14. After detaching from soils, the salt crust still experiences water condensation and salt deliquescence at the bottom, brine transport across the crust driven by the humidity gradient, and continued air-side precipitation. This transport mechanism allows salt crust migration away from the soil surface at a rate of 5 μm/h forming salt domes above soil surfaces. The surface characteristics of mineral substrates and the evaporation rate affect the morphology and the crystal size of precipitated salt. In particular, substrate hydrophobicity and low evaporation rate suppress salt spreading.
CitationDai S, Shin H, Santamarina JC (2015) Formation and development of salt crusts on soil surfaces. Acta Geotechnica 11: 1103–1109. Available: http://dx.doi.org/10.1007/s11440-015-0421-9.
SponsorsThis work has been supported by the Goizueta Foundation and US Department of Energy. Constructive comments from two anonymous reviewers have greatly improved this manuscript.