| Abstract |
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This paper examined the geotechnical properties of lateritic soils modified with coconut shell and husk ash with a view to obtaining a cheaper and effective road stabilizer. After collecting samples A, B and C from three borrow pits meant for road construction works, we performed preliminary tests on them for identification and classification purposes, followed by the consistency limit tests. We also performed engineering property tests (compaction, California bearing ratio (CBR) and triaxial) both at the stabilized and unstabilized states with the addition of 2, 4, 6, 8 and 10% coconut shell and husk ash (CSHA) contents. The results showed that the soil samples were well graded sand with good to excellent rating as subgrade material for pavement construction. However, the engineering properties of the samples were further improved with the addition of 4% CSHA contents. This caused reductions in the PI of samples A and C from 20.43 to 16.74% and 29.51 to 15.67% respectively and reduction at 2% of CSHA in sample B. We obtained optimum values of maximum dry densities (MDD) and shear strengths at 4% CSHA stabilization. The addition of CSHA increased the values of shear strengths to 136.32, 146.91 and 127.96 kN/m2 whereas MDD increased to 1939.00, 1749.86 and 2080.25kg/m3 respectively in samples A, B and C. We therefore concluded that coconut shell and husk ash has a good potential for improving the geotechnical properties of lateritic soils. |
