Abstract:
This research determined the geotechnical properties of lateritic soil modified with oil palm
fronds ash, sweet orange leaves ash and banana leaves ash respectively with a view to
obtaining a cheaper and effective replacement for the common stabilizers. Preliminary tests were performed on the lateritic soil sample for identification and classification purposes. Geotechnical strength tests such as; Compaction, Unconfined compressive strength tests,Shear Strength tests and California bearing ratio (CBR), were also performed on the samples,both at the stabilized and unstabilized states (adding 2, 4, 6, 8 and 10 % ashes of oil palm fronds, sweet orange leaves and banana leaves respectively). The results showed that the aforementioned additives improved the geotechnical properties of the soil samples. Optimum moisture content increased from 10.7 % to 16.60 % (highest value for palm fronds ash,obtained at 10 %). While the MDD increased from 1.94 kg/m3 to 2.02 kg/m3 (highest value for palm frond ash, obtained at 4 %). For the banana leaves ash, the Optimum moisture content increased from 10.7 % to the highest value of 14.8 % at 10 %, while the MDD increased from 1.94 kg/m3 to 1.99 kg/m3. Optimum moisture content of sweet orange leaves ash increased from 10.7 % to 14.01 %, while MDD increased from 1.94 kg/m3 to 2.00 kg/m3. The CBR increased from 10.42 % to 32.60 % (for palm frond ash), 28.81 % (for orange leaves ash) and 28.01 % (for banana leaves ash).The unconfined compressive strength and shear strength increased from 209.18 kN/m2 and 104.54 kN/m2 respectively at 0 % (no additives added) to 218.41 kN/m2 and 109.02 kN/m2 at 2 % ashes of orange leaves. The UCS was 233.78 kN/m2 and shear strength was 116.89 kN/m2 at 4 % ashes of banana leaves. While the UCS was 234.86 kN/m2 and shear strength was 117.43 kN/m2 respectively at 4 % ashes of
palm fronds leaves respectively. Based on the results obtained from the study, the treatment of lateritic soil with 2 %, 4 % and 6 % of ashes of banana leaves, 2 % and 4 % of ashes of orange leaves and 2 %, 4 %, 6 % and 8 % of ashes of palm fronds will effectively stabilize thelateritic soil. The use of these ashes should be restricted to the subbase of the road pavement, also, engineering confirmatory test should be carried out before embarking on any road construction project.
