## 5 Changes in Rock Properties with Increasing Freeze-Thaw Cycle
### Determination of Freeze-Thaw Temperature and Time  
The freeze-thaw test is an artificial weathering test to reproduce the physical weathering caused by tensile forces that occur during the formation of ice crystals within rocks. The freeze-thaw temperature range and time cycle can be applied differently depending on the study objectives and target region. Freeze-thaw test methods for durability of rocks are described in ASTM D5312 [34]. The temperature range for the freeze-thaw tests proposed by ASTM D5312 [34] is from \(-18\pm 2.5\)\({}^{\circ}\)C to \(+32\pm 2.5\)\({}^{\circ}\)C. [PERSON] and [PERSON] [14] and [PERSON] and [PERSON] [27] performed freeze-thaw tests using a temperature range of \(-20\)\({}^{\circ}\)C\(+20\)\({}^{\circ}\)C. [PERSON] et al. [15] and [PERSON] and [PERSON] [35] conducted freeze-thaw tests with a range of \(-22\)\({}^{\circ}\)C\(-\)\(+77\)\({}^{\circ}\)C, and [PERSON] [36] conducted a test with a range of \(-10\)\({}^{\circ}\)C\(-\)\(+150\)\({}^{\circ}\)C. Recently, freeze-thaw tests have been performed to compare climatic conditions at regions where rocks have been collected [10]. [PERSON] and [PERSON] [37] observed the largest effect of decreased hardness due to freezing at a temperature of \(-20\)\({}^{\circ}\)C.  
For the freeze-thaw temperature range in the present study, we applied a range of \(-25\pm 2\)\({}^{\circ}\)C\(-\)\(+27\pm 2\)\({}^{\circ}\)C for the temperature inside the rocks, accounting for the air temperatures in the Ny-Alesund region in the last 5 years (the maximum of 14 \({}^{\circ}\)C and the minimum of \(-24\)\({}^{\circ}\)C). The reason of applying the higher maximum temperature (\(+27\pm 2\)\({}^{\circ}\)C) compared with the five-year maximum temperature (\(+14\)\({}^{\circ}\)C) is to consider possible heat transferred from ground and solar radiation to the rock surface. In order to determine the freeze-thaw time, temperature changes inside the rock specimens were measured. For the measurement of rock temperature, small hole of 5 mm (diameter) \(\times\) 25 mm (depth) is drilled at both ends of cylindrical rock samples with dimension of 50 mm (diameter) \(\times\) 100 mm (length). The t-type thermocouple is firmly attached to center of the hole bottom. Thermal isolation was done by inserting bonding chemicals into the drilled holes. After drilling to the centers of the largest freeze-thaw specimens (diameter of 49.5 mm and length of 100 mm), we inserted a temperature sensor to monitor temperature changes on the inside the rock specimens. After saturating the test specimens in a vacuum chamber for 24 h, the specimens were submerged in individual containers filled with tap water for freeze-thaw. Figure 5 shows the temperature curves inside the rock when the temperature in the freezing chamber was changed in the range \(-25\pm 2\)\({}^{\circ}\)C\(-\)\(+40\pm 2\)\({}^{\circ}\)C.  
Figure 4: Minimum and maximum daily air temperature variation measured at Dasan station at Ny-Alesund of years (**a**) 2015 (maximum freeze-thaw cycles of 62) and (**b**) 2017 (minimum freeze-thaw cycles of 33). Although the change in temperature inside the rock sample exhibited some small changes with each freeze-thaw cycle, it took approximately 30 min for the rock temperature to descend from air temperature (+15 \({}^{\circ}\)C) to 0 \({}^{\circ}\)C, and the freezing temperature (-25 \({}^{\circ}\)C) was maintained for around 2 h. The time for the temperature inside the rock to recover from \(-\)25 \({}^{\circ}\)C to +27 \({}^{\circ}\)C was around 2 h 30 min. By measuring the change in temperature inside the rocks, we determined the duration of freeze-thaw cycles.