Effect of Cassava Peel Ash on the geotechnical properties of some selected Lateritic Soil in Osun State.
Obafemi Awolowo University
This study is aimed at assessing the effect of Cassava Peels Ash (CPA) on the stabilization of lateritic soil with a view of improving its geotechnical properties. Lateritic soil samples were collected from three different locations namely, Ife-East, Ayedaade and Olorunda Local Government Areas in Osun state, Nigeria, and were termed sample A, B and C, respectively. Cassava Peels were procured from a local cassava processing factory at Oke-Baale, Osogbo, Osun State. The chemical composition of the soil samples and the CPA, and the geotechnical properties such as grain size, liquid limit (LL), plastic limit (PL), optimum moisture content (OMC), maximum dry density (MDD), California bearing ratio (CBR) and unconfined compressive strength (UCS)of the soil samples were determined in their natural states. The Cassava Peels (CP) were dried and calcined at 700oC for a period of 90 minutes in an electric furnace and the ash produced sieved through 425 µm sieve. The resulting CPA was added to the soil samples in incremental values of 2, 4, 6, and 8% by weight of the dry soil. Each soil sample was equally mixed with 4% lime by weight of the soil. The aforementioned geotechnical properties were determined for each Soil-CPA-Lime mixture. The data obtained from the tests were used to establish the optimum percentage of CPA. The results showed that the soil samples as well as CPA contain between 34 and 42% silicon dioxide. The soil samples are acidic with pH ranging from 4.2 to 5.8. Whereas the CPA is basic (pH = 11.4). On addition of CPA and lime, the LL of sample A increased from 39.0 to 41.2%, sample B decreased from 46.2 to 36.7% and sample C decreased from 35.8 to 33.4% at the ratios of 2, 2 and 4% CPA, respectively. The PI for soil sample A decreased from 3.6 to 1.7%, sample B decreased from 16.1 to 2.3% and sample C decreased from 12.4 to 2.6% at the ratios of 2, 2 and 4% CPA, respectively. The MDD generally increased for all the soil samples as % CPA increased. The MDD increased from 1558 to 2020 kg/m3, 1850 to 2080 kg/m3 and 1110 to 1940 kg/m3at the ratios of 8, 4 and 4 % for samples A, B and C, respectively. The CBR for samples A, B and C increased from 18.0 to 25.0%, 21.0 to 27.0% and 17.0 to 18.0%, at the ratios of 8, 8 and 4% CPA, respectively. The result of the UCS tests generally increased as the % CPA increased. The highest values obtained were 400, 285, 215 kN/m2at the ratios of 8, 8 and 4% CPA for samples A, B and C, respectively. The study revealed that a combination of CPA and lime has the potential of improving the geotechnical properties of lateritic soil but no optimum percentage of CPA could be established for the studied soil samples.
Cassava peels ash, lateritic soil, Ife-East, Ayedade and olorunda local government, Osun state, Nigeria
Mgboh,C.V.(2015).Effect of cassava Peel Ash on the geotechnical properties of some selected lateritic soil in Osun State