Experimental Investigation of the Size Effect of the Mode I Static Fracture Toughness of Limestone

Table 2

Analysis data of the NSCB sample.

Sample number	Maximum load, (N)	Test value of fracture toughness, KIc (MPa·m^1/2)	True value of fracture toughness	Length of the fracture zone, Cf (mm)
NSCB25-1-1	1366	1.123	1.203	1.911
NSCB25-1-2	1358	1.155	1.226	1.887
NSCB25-1-3	1052	0.944	1.316	1.812
NSCB25-2-1	762	0.978	2.112	18.445
NSCB25-2-2	492	0.606	2.034	18.524
NSCB25-2-3	570	0.706	2.056	18.500
NSCB25-3-1	400	0.686	1.567	10.378
NSCB25-3-2	402	0.676	1.555	10.373
NSCB25-3-3	476	0.811	1.562	10.376
NSCB37.5-1-1	2788	1.280	1.268	1.849
NSCB37.5-1-2	2062	1.068	1.406	1.758
NSCB37.5-1-3	2402	1.105	1.272	1.845
NSCB37.5-2-1	1646	1.064	2.010	18.555
NSCB37.5-2-2	1618	1.067	2.024	18.537
NSCB37.5-2-3	1864	1.170	1.969	18.612
NSCB37.5-3-1	1206	1.091	1.579	10.383
NSCB37.5-3-2	1137	1.108	1.676	10.431
NSCB37.5-3-3	1004	0.972	1.674	10.430
NSCB50-1-1	4174	1.376	1.362	1.782
NSCB50-1-2	3146	1.033	1.358	1.785
NSCB50-1-3	4130	1.339	1.346	1.792
NSCB50-2-1	2770	1.213	2.036	18.522
NSCB50-2-2	2876	1.238	2.012	18.552
NSCB50-2-3	2550	1.101	2.018	18.545
NSCB50-3-1	1530	0.950	1.642	10.413
NSCB50-3-2	1820	1.144	1.641	10.412
NSCB50-3-3	1860	1.111	1.581	10.384
NSCB75-1-1	7300	1.262	1.317	1.811
NSCB75-1-2	7124	1.120	1.336	1.799
NSCB75-1-3	7942	1.382	1.315	1.813
NSCB75-2-1	4592	1.072	2.027	18.533
NSCB75-2-2	5432	1.356	2.162	18.406
NSCB75-2-3	4936	1.224	2.146	18.417
NSCB75-3-1	3182	1.109	1.694	10.441
NSCB75-3-2	3684	1.250	1.669	10.427
NSCB75-3-3	3304	1.130	1.652	10.418