Effect of mineralogical composition on the geotechnical properties of clay found in Lokoja

Abstract

ABSTRACT Clay soils are commonly found in various regions around the world and play a significant role in geotechnical engineering projects. This thesis aims to investigate the effect of clay soil mineralogy on geotechnical properties. Clay soil samples were collected from three different locations around Lokoja, Kogi State, North Central Nigeria and tests carried out on the samples includes X-ray diffraction analysis (XRD), Specific Gravity, Natural Moisture Content (NMC), index properties (sieve analysis, liquid limit and plastic limit), Universal Compressive Strength (UCS) and California Bearing Ratio (CBR). From the results, the major minerals in the three different samples are rutile, muscovite and cristobalite respectively, the natural moisture content ranged from 10.8 to 19 percent while the specific gravity of the sample is between 2.48 and 2.55. Test results also showed that the clays have high plasticity index, averaging 19.1%, and a moderate average liquid limit of 38.70%. For the strength properties, the universal compressive strength (UCS) test shows very low values ranging from 242kN/m2 to 379kN/m2 and low CBR values indicating that the soils are very poor for pavement construction. The clay minerals have fairly poor geotechnical properties but may possess significant economic values.