Petrography and Geotechnical Properties Sakessar Limestone, Nammal Gorgue in District Mainwali Punjab, Pakistan

Abstract This study evaluates the petrographic and geo-mechanical properties of the Sakessar Limestone in the Nammal Gorge, District Mianwali, Punjab, Pakistan, to evaluate its suitability for construction applications. The limestone, exposed in the western Salt Range near Nammal Dam, features an approximate thickness of 18 meters and displays an off-white to grey coloration, primarily consisting of fractured limestone with chert nodules. Geotechnical tests conducted include unconfined compressive strength (UCS), water absorption, specific gravity, porosity, unconfined tensile strength (UTS), soundness, Schmidt hammer, and point load tests. Results indicate water absorption values between 0.21% and 0.37%, specific gravity ranging from 2.607 to 2.670, and porosity from 0.5–0.97%. UCS values of 19.2 to 59.7 MPa suggest moderate to high strength, with UTS values ranging from 4.44 to 9.51 MPa and UCS/UTS ratios from 2.4646 to 8.243. Soundness tests using sodium sulfate yielded a value of 1.2%. Petrographic analysis classifies the limestone as Wackestone, containing over 30% grains, less than 5% cement, and a significant matrix component. Overall, the physical, mechanical, and petrographic properties indicate that Sakessar limestone is suitable for use as a construction material.