Comparisons of mechanical properties between dry and floating saline ice

Experimental characterization of saline ice behavior is the basis of sea ice modeling. In many previous laboratory experiments, relatively cold, isothermal and dry ice specimens have been used instead of warm specimens or specimens floating in water. Even for the case of field experiments, sea ice specimens are often taken out of the seawater for testing. Therefore, the sea ice is often not tested under its natural conditions. Whether the dry and isothermal saline ice specimens behave similarly to floating specimens with the same average temperature, but with a naturally occurring temperature gradient, has been lacking assessment. In this study, uniaxial cyclic compression tests were carried out on laboratory-prepared saline ice under both dry and floating conditions. Our dry saline specimens showed ≈21% higher average elastic modulus than the corresponding floating specimens, although their average temperatures, salinities, bulk densities and porosities were approximately constant. Moreover, the floating specimens present much more pronounced rheological behavior than the dry specimens. Thus, our preliminary results indicate that the mechanical properties of dry and floating saline ice differ significantly.