Effect of organic carbon on the physico-mechanical characteristics and durability of the Gohareh limestone subjected to a heating-cooling process

The Gohareh limestone is the most common building stone used in buildings under construction in the Lorestan Province, Iran. Limestone contains organic carbon (OC), which can affect its inherent characteristics and durability against environmental deterioration processes. Any change in the inherent characteristics and durability can lead to a loss of quality of limestone and thus its service life in a building. In the present study, the effects of OC on the physico-mechanical characteristics and durability of the limestone subjected to a heating-cooling (HC) process, a temperature up to 70 degrees C, were investigated. The porosity (n), uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), and P-wave velocity (Vp) of the limestone with different OC contents were determined. These characteristics were also determined after every 10 cycles of HC test for up to 60 cycles. The changes in the appearance and pore space of deteriorated limestone due to the effects of HC were investigated via visual inspection and scanning electron microscopy, respectively. The findings indicate a loss in the physico-mechanical characteristics of the limestone with increasing OC. Moreover, it was found that limestone specimens with higher OC showed greater loss in their physico-mechanical characteristic during HC. These results were consistent with the findings of appearance damage and pore space modification in the limestone specimens after the HC process. The results of the present study can be applied to OC-containing limestones from other regions of the world whose OC and physico-mechanical characteristics are within the range of values obtained for the studied limestone.