Strength Anisotropy in Stylolitic Limestone

A stylolite is a common sedimentary feature acting as a weakness plane in sedimentary rocks, especially carbonates. This sedimentary feature can cause anisotropic behaviors in some inherent properties of rock. The present study investigated the effect of a stylolite plane containing clay mineral as the filling material, in both the dry and saturated states, on the behavior of uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS) of limestone widely used in building applications. Specimens at different angles of the stylolite plane (β), namely, 0°, 30°, 45°, 60°, and 90° (β is the angle between the stylolite plane and loading axis), taken from limestone under both dry and saturated conditions, were subjected to UCS and BTS tests. The findings indicate anisotropic behaviors of the UCS and BTS of the sample as a function of β. Moreover, the values of UCS and BTS are strongly affected by water effects, such that the sample suffers significant reductions in these properties after being saturated. Overall, the results show that β, the type of filling material, and test specimen state (i.e., dry or saturated) should be considered for a more accurate assessment of limestone quality. When taking these factors into account, the limestone used in a building is expected to have a longer service life.