Fig. 7

The strain produced by the solidification of menthol melt (60 ℃) on the Yungang sandstones. a 2 strain gauges setup (2 mL melt applied on an area of 18 mm × 18 mm, thickness is around 10 mm); b 4 strain gauges setup (2 mL melt applied on an area of 25 mm × 75 mm, thickness is around 2 mm); c 2 strain gauges setup (1 mL melt applied on a larger sandstone sample, applying area is about 60 mm in diameter and 1 mm in thickness)