Weathering Influence on Properties of Siltstones from Istria, Croatia

Table 4

Results of five cycles of the slake durability tests, including the slake durability index, degradation ratio, and modified degradation ratio, for siltstones of different weathering grades in the study area.

Weathering grade	Sample number	Sampling location	First cycle	Second cycle	Third cycle	Fourth cycle	Fifth cycle
			Slake durability index ()
			[%]	[%]	[%]	[%]	[%]
I (FR)		Sovinjak	94.71	88.31	82.16	76.75	72.60
III (MW)			94.35	89.69	85.34	80.97	76.75
I (FR)		Cunj	98.15	97.03	95.99	94.96	94.01
III (MW)			97.41	95.39	93.40	91.45	89.52
I (FR)			98.76	97.82	96.41	95.51	94.24
III (MW)			98.64	97.73	96.32	95.52	94.45
			Degradation ratio ()
			I (FR)		Sovinjak	0.69	0.65	0.61	0.58	0.55
III (MW)		0.69	0.60	0.56		0.53	0.50
I (FR)		Cunj	0.84	0.81	0.79	0.78	0.76
III (MW)			0.82	0.79	0.75	0.72	0.69
			Modified degradation ratio ()
			I (FR)		Sovinjak	0.30	0.35	0.39	0.42	0.50
III (MW)		0.31	0.41	0.45		0.47	0.50
I (FR)		Cunj	0.16	0.20	0.21	0.22	0.24
III (MW)			0.18	0.22	0.25	0.28	0.31