Document Type : Original Research Paper
Author
Department of Geology, Faculty of sciences, Lorestan University, Khorramabad, Iran
Abstract
Limestone is a sedimentary rock widely used as building stone in many regions of the world. Uniaxial compressive strength (UCS) is one of the most important technical parameters in assessing the quality of building stones. A stylolite is a common structural feature that acts as a plane of weakness in limestone, which can significantly affect its UCS. In the present study, the effects of stylolite filling material composition and specimen water content on the UCS of limestone were investigated. For this purpose, the UCS of limestones without stylolite (WS) and those containing stylolite planes filled with clay (FMc), organic matter (FMom), and iron oxide (FMio) were determined under both dry and saturated conditions. The results showed that stylolite caused a significant UCS reduction of up to 29.5% in limestones FMc, FMom, and FMio (UCS = 44.9, 51.7, and 56.4 MPa, respectively) compared to limestone WS (UCS = 63.7 MPa). Furthermore, the ratios of saturated to dry UCS were found to be 0.54, 0.68, 0.78, and 0.96 for limestones FMc, FMom, FMio, and WS, respectively, highlighting the detrimental effect of water content on UCS. Consequently, stylolite-free limestone is highly preferable for structural applications, whereas clay-filled stylolitic limestone should be avoided due to severe UCS degradation. Finally, although the proposed classification of stylolite filling material composition and specimen water content provides a practical basis for selecting higher-quality limestone from a UCS perspective, future research is necessary to improve the reliability of UCS evaluation for stylolitic limestones from other regions of the world.
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