Assessment of Physical and Mechanical Properties of Granitic Rock at University of Abuja

Abstract

A study on the assessment of physical and mechanical properties of granitic rock at University of Abuja was carried out. The research involved field work, laboratory testing and analysis of rock samples to determine their mineralogical properties, and compressive strength. The granitic gneiss outcrop at University of Abuja is a massive and elongated ridge trending NW-SE for about 2.8 km with a coarse-grained texture of gradual lineation of quartz and feldspar in places. Petrographic studies revealed biotite flakes in the granitic gneiss appeared thin as a result of deformation and are aligned in parallel to sub parallel style surrounding large crystals of feldspar to disclose some evidence of strain. Field occurrence of the gneisses revealed that the rocks have undergone intense heat and pressure, resulting in the formation of high-grade metamorphic rocks with bands of felsic to mafic minerals. Granitic gneiss predominates in the area having quartz, feldspar, muscovite and biotite mica ± hornblende and iron oxides. Correlation of mineralogical composition in granitic gneiss rocks with its compressive strength in the study area revealed that quartz is positively correlated with compressive strength, biotite is positively correlated with compressive strength and muscovite is also positively correlated with compressive strength while iron oxide and feldspar are negatively correlated with compressive strength. In gneiss, quartz, muscovite and iron oxides are positively correlated with compressive strength, while biotite and feldspar are negatively correlated with compressive strength.