Investigation of Sandstone Mesostructure Damage Caused by Freeze-Thaw Cycles via CT Image Enhancement Technology

Table 2

Damage variables and number of damage regions.

Freeze-thaw cycles	Fine-grained sandstone M1			Coarse-grained sandstone A1
	AD (mm^2)	Number of damage regions, N,	Df (%)	AD (mm^2)	Number of damage regions, N	Df (%)
0	23.60	11	1.25	32.76	17	1.64
20	45.21	14	2.39	114.72	25	5.74
40	93.18	23	4.94	560.07	39	28.06
60	175.83	25	9.33	830.64	26	41.62
80	469.71	20	24.92	902.07	17	45.20
100	497.40	19	26.39	1417.56	5	71.03