**3. Laboratory testing program and methods**

Laboratory tests were performed in two types of limestone to examine timeeffects in brittle materials. The selected Jurassic limestone comes from a quarry north of Zurich, Switzerland (**Figure 9a**). The Cobourg limestone (**Figure 9b**) comes from the Bowmanville quarry near Bowmanville, Ontario, Canada. It should be noted that sample preparation were conducted according to ISRM [42].

Unconfined Compressive Strength (UCS) tests were conducted on 10 cylindrical samples of Jurassic and 9 of Cobourg. Relaxation tests were conducted on 19 Jurassic and 16 Cobourg samples. Static Load tests were performed on 12 Jurassic and 5 Cobourg samples.

**Figure 9.** *Samples of (a) Jurassic limestone, (b) Cobourg limestone.*

*Time-Dependent Behavior of Rock Materials DOI: http://dx.doi.org/10.5772/intechopen.96997*

**Figure 10.**

*Stress-strain response of limestone: (a) Jurassic samples and (b) Cobourg samples tested in unconfined compressive strength conditions.*
