Engineering Geological Evaluation of Some Clay Deposits in Dahomey Basin Southwestern Nigeria

Qualitative evaluations of clay deposits in Erusu-Akoko, Southwestern, Nigeria, were executed with a view to determining its quality and possible utilities. Four representative bulk samples were collected and subjected to geotechnical analysis which included; grain size analysis, bulk density, unconfined compression strength test, modulus of rupture, permeability, compaction and mineralogy of analysis. The result of the geotechnical analysis showed that the liquid limit ranged from 48.30 –52.30 % with a mean value of 50.10 % and its plasticity index limit ranged from 26.0 – 31.9 with a main value of 20.30 % which is an indication of intermediate plasticity. The plastic limit ranged from 26.0 – 31.90 % with a mean value of 29.4 % which implies that the clay can withstand volumetric shrinkage on heating and exhibit a low to medium swelling potential when wet. The amount of fine fractions about 60.41 – 75.32 %, clay sized fractions about 10 – 22 %, average compressive strength 230 kpa, average bulk density 2.03 g/cm3, average porosity 27.4 %, average compaction 1.92 %, permeability coefficient 1.7 x 10-5 cm/s, average firing temperature 1350oC and average modulus rupture 1100oC showed that the clay possesses properties of a good liner for landfill, pottery, refractory materials and firebricks. The study showed that the clay deposits in the study area can be used for the production of ceramic, pottery, firebricks, blast furnace for metals and refractories.