CHARACTERIZATION OF SELECTED SEDIMENTARY ROCK TYPES FOR ENGINNERING APPLICATIONS, KOGI STATE, NIGERIA

Abstract

The study investigated the characterization of selected sedimentary rock types in Kogi State for engineering applications. In situ and laboratory tests were conducted on the sandstone and shale which are the selected sedimentary rocks. Schmidt hammer was used to carry out in situ testing of the rock on the field and samples were collected for laboratory tests. Four samples of each rock type were prepared for the determination of density and porosity values. The results obtained from the Schmidt hammer test and those of density determined from laboratory test were used to estimate the uniaxial compressive strength of the rock. Point load and tensile strengths were determined from laboratory test. The average density of sandstone is 2.08 g/cm3 and that of shale is 2.40 g/cm3. The average porosities of sandstone and shale are 13.0% and 34.8% Respectively. The average uniaxial compressive strength values of sandstone and shale are 26.3MPa and 34.2 MPa respectively. The average point load strength index values of sandstone and shale are 1.17 MPa and 1.51 MPa respectively. The average tensile strength values of sandstone and shale are 1.76 MPa and 2.27 MPa respectively. Statistical analysis was carried out on the determined physical and mechanical properties using SPSS software to determine their correlation. Mathematical model were derived from statistical analysis and the derived models were tested. The results show that there are strong relationships between the two properties. The uniaxial compressive strengths of the rocks fall in the range of high strength. The point load and tensile strength also fall in the range of high strength. The sandstone and shale rock types from the selected locations are considered to have good engineering properties for construction works.