Fracture Characteristics of Polyurethane Grouting Materials Based on Acoustic Emission Monitoring

Table 6

Average compressive strength of sand-containing samples.

Group of specimens	Number of specimens	Average compressive strength (MPa)
Group I	1	1.25	1.09
	2	0.97
	3	0.89
	4	1.25
Group II	5	0.79	0.85
	6	1.08
	7	0.88
	8	0.66
Group III	9	0.96	1.13
	10	1.31
	11	1.37
	12	0.88
Group IV	13	0.94	0.82
	14	1.08
	15	0.55
	16	0.72