Freeze Bond Strength Development and Properties in Prolonged Submersion Times and Implications on Ice Rubble Strength

This paper summarizes the finding of an extensive experimental campaign conducted at Memorial University of Newfoundland, focusing on understanding shear strength properties of freeze-bonded ice blocks. A series of Asymmetric Four-Point Bending (AFPB) tests were conducted, focusing on the effects of submersion time for two initial ice temperatures of -10 and -18 degrees, subject to a normal pressure of 25 kPa. Freeze bonds were then sheared at an actuator rate of 5 mm/ls. Freeze bond strength development can be separated into 5 stages, where bond strength increased with increase in submersion time in stage 1, reaching a peak after only 4 minutes of submersion, followed by a decrease in strength in stage 2, as ice reached equilibrium temperature with water. Freeze bond strength stayed at a constant low in stage 3. Freeze bond strength was seen to increase again in stage 4, eventually reaching the strength of solid ice in stage 5. This paper focuses on understanding the mechanisms that occur in stage 4 and 5 of freeze bond strength development. During these stages, freeze bond strength was observed to increase with increase in submersion time as submersion time increased from 24 hours to 2 weeks, and reaching the strength of solid ice after 1 week for ice with initial temperature of -10 degrees, and after 2 weeks for ice with initial temperature of -18 degrees.