Mechanical stabilization of a migmatite-gneiss derived lateritic soil from ibadan, southwestern nigeria

Abstract

Samples of migmatite-gneiss-derived lateritic soil from Moniya, Ibadan southwestern Nigeria were stabilized with between 0 and 20% by volume of nearby termite-reworked soil under different energies of compaction. This was with a view to determining the influence of termite-reworked soil on some engineering properties of the soil. The amounts of termite-reworked soil mixed with the adjacent residual lateritic soil prior to compaction were 0, 10 and 20%, while each mixed soil was subjected to 10, 20, 30, 40, 50 and 60 blows of a 4.5 Kg Rammer falling from a height of 0.46 metre during compaction. Strong positive correlations of 0.94 and 0.99 were established between the maximum dry density and the percentage of volume of stabilizer of the samples compacted with 30 and 60 blows respectively. Negative correlations of-0.87 and-0.91 were found between the optimum moisture content and percentage of termite-reworked soils compacted at 30 and 60 blows respectively. The highest uncured and sun-cured compressive strength of 206KPa and 2148KPa were `respectively The influence of termite-reworked soils on the compaction characteristic of the soil thus increases with the energy of compaction. The influence of stabilization with termite-reworked soil on the unconfined compressive strength of the soil was found to be strongest upon compaction at highest levels for the sample stabilized with 20%by volume of termite-reworked soil. The highest unsoaked CBR value of 42.83% and soaked CBR value of 16.20% were obtained when 20% by volume of stabilizer was added to the soil. This implies that the influence of stabilizer was strongest when 20% by volume of termite-reworked soil was added to the studied soil. Results showed that the termite-reworked soil samples had better geotechnical properties than the soil developed over migmatite-gneiss based on the grading and plasticity characteristics. Compaction parameters, unconfined compressive strength and California Bearing Ratio of the stabilized samples were found to be significantly improved when compacted with 20% by volume of the termite-reworked soil. The sun-cured unconfined compressive strength of 2148KPa obtained for samples compacted at the modified American Association of the State Highways and Transportation Officials level shows they can be good for building bricks and road construction.