Response of Dry and Floating Saline Ice to Cyclic Compression

Laboratory experiments on saline ice are often performed on cold, isothermal and dry specimens out of convenience versus working with warm specimens or specimens floating in water. The laboratory conditions, thus, usually involve non-natural conditions. This study compares cyclic loading experiments covering the main range of ocean wave periods performed on both dry, isothermal and warm, floating ice specimens. Results indicate that −2.5°C isothermal dry specimens have higher moduli than floating specimens with an average temperature of −2.5°C with a naturally occurring temperature gradient. Moreover, the dislocation density estimated using a physics-based model and the strain energy density dissipated in 10⁻³–10⁻² Hz loading-unloading cycles are much lower for the −2.5°C dry specimens than for the −2.5°C floating specimens. Although the precise reason for the dislocation density difference requires further study, the results nonetheless contribute to the understanding and implementation of ice rheology and related geophysical modeling.