Equilibrium and non-equilibrium freezing of water in clay-water systems

• Autorzy: Kozłowski T.
• Języki publikacji: EN

Abstrakty

EN

The temperature of spontaneous nucleation Tsn and the equilibrium freezing point Tf were determined for six monomineral, homoionic clayey soils by use of the Differential Scanning Calorimetry (DSC) technique. The temperature of spontaneous nucleation Tsn was determined on the cooling run, as the initial temperature of the observed exothermic peak. The temperature of equilibrium freezing (or melting) Tf was comprehended as the initial temperature of the last non-zero thermal impulse in the diagram of real thermal impulses distribution q(T) obtained on warming.The supercooling was calculated as the difference between Tf and Tsn. The obtained results testify the strong dependency of the equilibrium freezing point Tf on the water content w. It has been proved that Tf can be expressed as a power function of water content wand the limit of plasticity with a high correlation coefficient (R=0.933) showing a good fit to the experimental data. In contrary, a scatter of results was observed for Tsn and [...], which could be related to the effect of factors other than the water content. The diagrams of the supercooling vs. the water content suggest a relationship with an extreme. The critical water content, Wcr at which the supercooling reaches a maximum, was found by use of a quadratic empirical model. For all the clay-water systems, the criitical water content Wcr occurs between the plastic limit Wp and the liquid limit W_L.'

Słowa kluczowe

EN

clay-water systems; scanning calorimetry; freezing; temperature of spontaneous nucleation

PL

system glina-woda; kalorymetr skaningowy; zamarzanie; temperatura krystalizacji

• Wydawca: Oficyna Wydawnicza Uniwersytetu Zielonogórskiego
• Czasopismo: Civil and Environmental Engineering Reports
• Rocznik: 2009
• Tom: No. 3
• Strony: 77--91
• Opis fizyczny: Bibliogr. 12 poz., rys., tab.

Twórcy

autor

Kozłowski T.

• Politechnika Świętokrzyska w Kielcach

Bibliografia

• 1.Akyurt M., Zaki G., Habeebullah B.: Freezing phenomena in ice-water systems. Energy Conversion and Management, 43, 1773-1789, 2002.
• 2.Anderson D. M.: Ice nucleation and the substrate-ice interface. Nature, 216, 563-566, 1967.
• 3.Anderson D. M.: Undercooling, freezing point depression, and ice nucleation of soil water. Israel J. Chem., 6, 349-355, 1968.
• 4.Bozhenova A. P.: Pereochlazhdenie vody pri zamerzanii yeyo v pochvo-gruntach. Mat. po lab. issl. merz. gruntov, Sb. 1, 144-156, 1953.
• 5.Fletcher N. H.: The chemical physics of ice. Cambridge Univ. Press 1970.
• 6. Franks F.: Water. Cambridge Univ. Press. 1983.
• 7.Kozłowski T.: Investigation of the supercooling in clayey soils. Frost in Geotechnical Engineering. Technical Research Centre of Finland, VTT 94, Vol. I, 293-300, 1989.
• 8.Kozłowski T.: A comprehensive method of determining the soil unfrozen water curves; 1: Application of the term of convolution. Cold Regions Science & Technology, 36(1-3), 71-79, 2003.
• 9.Kozłowski T.: Soil freezing point as obtained on melting. Cold Regions Science & Technology, 38(2-3), 93-101, 2004.
• 10.Low P.F., D.M. Anderson D. M., Hoekstra P.: Some thermodynamic relationships for soils at or below the freezing point; 1, Freezong point depression and heat capacity. Wat. Res. Res., 4, 379-394, 1968.
• 11.Pruppacher H. R.: Some relation between the structure of the ice-solution interface and the free growth rate of ice crystals in supercooled aqueous solutions. J. Colloid Interface. Science, 25, 285-294, 1967.
• 12.Usu J., Sano J.: On the freezing of the droplets of aqueous solutions. J. Met, Soc. Japan, 43, 114-137, 1965.